WO2004089833A2

WO2004089833A2 - Method and plant for treatment of organic waste material

Info

Publication number: WO2004089833A2
Application number: PCT/DK2004/000262
Authority: WO
Inventors: Jens Østergaard JENSEN
Original assignee: STARING MASKINFABRIK AS
Current assignee: STARING MASKINFABRIK AS
Priority date: 2003-04-11
Filing date: 2004-04-07
Publication date: 2004-10-21
Anticipated expiration: 2005-10-11
Also published as: WO2004089833A3

Abstract

The present invention relates to a method of and a plant for treatment of an organic waste material containing an aqueous phase and a solid phase. The invention involves separation and purification of the organic waste material. The organic waste material may be manure from livestock production being separated into an enriched solid phase containing nutrients, such as ammonium, phosphor and potassium, and a purified aqueous phase. It is preferred to introduce and subject the organic waste material to at least one coagulant, at least one flocculating agent and to allow association between negatively charged solid material and cations of the organic waste material. The invention is capable of obtaining a dry matter content of the organic waste material. The invention is capable of obtaining a dry matter content of the organic waste material below 20% wt.

Description

METHOD OF TREATMENT OF AN ORGANIC WASTE MATERIAL INVOLVING SEPARATION AND PURIFICATION AND A PLANT FOR SUCH A TREATMENT

FIELD OF THE INVENTION

The present invention relates to a method of treatment of an organic waste material containing an aqueous phase and a solid phase. The invention involves separation and purification of the organic waste material. The organic waste material may be manure from livestock production being separated into an enriched solid phase containing nutrients, such as ammonium, phosphor and potassium, and a purified aqueous phase. Furthermore, the invention relates to a plant in which the organic waste material is treated, involving separation and purification.

BACKGROUND OF THE INVENTION

Today, one of the main issues in relation to livestock production is the concomitant formation of organic waste material. Intensive production of animals, such as pigs, in particular leads to the formation of huge amounts of organic waste material representing an environmental handling problem. Especially, the nutrients in manure contribute to negative environmental consequences. In the future, still more effective livestock productions will undoubtedly be seen. Thus, while intensifying the livestock production, consequences to the environment will arise if the organic waste material is not handled correctly. The same issues exist in several other fields, such as in manufacturing industries, processing industries, fisheries, institutions and households.

Some attempts to separate organic waste material and thereby overcome some of the handling problems in relation to organic waste material have been provided. Separation of an organic waste material into two phases containing an aqueous phase and a solid phase in some circumstances may allow easier and more economically beneficial handling of the organic waste material.

Prior art describes such a separation process, where manure from livestock production essentially is treated with a coagulant and a flocculating agent in suitable dilutions. This treatment allows the manure to be separated into an aqueous phase and a solid phase. After the separation has taken place, nitrogen is concentrated in an aqueous concentrate and phosphor is concentrated in another aqueous concentrate, whereas the solid phase essentially consists of organic material. When phosphor is concentrated in an aqueous phase, the solid phase is represented by only a minor amount of phosphor. One object according to the present invention may be to obtain a nutritional enriched solid phase and a more diluted aqueous phase after separation of an organic waste material. The great advantage thereof may be to use the enriched solid phase as fertiliser and to obtain a substantially diluted aqueous phase being harmless to the earth and water environment. The enriched solid phase thus may be used as fertiliser without any further treatment, such further treatment traditionally involves much increased costs.

It is generally known that nutrients bound to organic material will be more resistant to leaching, and thus another object of the invention may be to associate the nutrients, such as nitrogen, phosphor and potassium, to the organic material to prevent leaching. Thus, preventing nutrients, such as nitrogen, phosphor and potassium from damaging the environment may be an overall object according to the invention.

An object of the invention may also be allowing a separation leading to an easier and more economical beneficial handling of the organic waste material. The usually unpleasant smell of ammonia that is potentially contained in organic waste material and potentially liberated, when the organic waste material is decomposed, may according to another object of the invention be limited. Still another object of the invention is to obtain a filtration process with a filter also being easier and economically more beneficial to handle.

Another object of the present invention apart from prior art treatment processes may be to improve producers' opportunities for removal of organic waste material, such as from livestock production, industries, fisheries, institutions or households. The producers are thus allowed an economic favourable deposit alternative, which in turn may increase the production, such as for livestock production, as a consequence of economically favourable and more environmentally safe treatment of the organic waste material.

SUMMARY OF THE INVENTION

One, more or all of these objects may, according to the present invention, be obtained by a first method of treatment of an organic waste material containing an aqueous phase and a solid phase, the method comprising the following steps:

(a) processing the organic waste material by

optionally, subjecting the organic waste material to at least one coagulant, thereby precipitating at least 90% wt. of the phosphor ions and initiating flocculation of the solid phase and thus excluding at least part of the anions from the aqueous phase, allowing at least part of the cations of the organic waste material to associate to negatively charged solid materiel, thereby excluding at least part of the cations from the aqueous phase, and

introducing at least one flocculating agent, thereby obtaining an at least partly diluted aqueous phase and an at least partly enriched solid phase; and

(b) separating the at least partly enriched solid phase obtained in step (a) from the at least partly diluted aqueous phase using a number of sieving members accumulating the at least partly enriched solid phase at the upper surface of the number of sieving members, thus in a controlled manner

allowing the at least partly diluted aqueous phase to traverse both the at least partly enriched solid phase and the number of sieving members, thereby letting at least part of the cations associate to negatively charged solid materiel, thereby

obtaining an at least partly purified first aqueous phase containing at the most 30% wt. of the nitrogen, at the most 40% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

Alternatively, one, more or all of these objects may according to the present invention be obtained by a second method of treatment of an organic waste material containing an aqueous phase and a solid phase, the method comprising the following further step of treatment:

(c) transferring the at least partly purified first aqueous phase obtained in step (b) to one or more reverse osmosis unit(s) separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the reverse osmosis unit(s), so that the at least partly purified first aqueous phase traversing the reverse osmosis unit(s) is further purified,

obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material, or transferring the at least partly purified first aqueous phase obtained in step (b) to one or more sub- filtration unit(s), preferably nano-filtration unit(s), separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the sub-filtration unit(s), so that the at least partly purified first aqueous phase traversing the sub-filtration unit(s) is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

Finally, one, more or all of these objects may according to the invention be obtained by a third method of treatment of an organic waste material containing an aqueous phase and a solid phase, the method essentially comprising:

subjecting an at least partly purified first aqueous phase of organic waste material to one or more positively charged resins containing at least divalent positively charged ions, the one or more positively charged resins repelling the cations, thereby

at least partly preventing the cations to traverse the one or more positively charged resins, so that the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified,

obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

Furthermore, according to the invention there is provided a plant for the treatment of the organic waste material containing a aqueous phase and a solid phase, obtaining one, more or all of the objects mentioned in the previous section, the plant comprising:

supply means for introducing the organic waste material to at least one process container, and said plant furthermore comprising

supply means for dosage of supply media to the at least one process container including supply means for dosage of at least one coagulant from a number of coagulant supply containers,

supply means for dosage of negatively charged solid materiel from a number of supply containers containing negatively charged solid material and supply means for dosage of at least one flocculating agent from a number of flocculating agent supply containers, and said plant furthermore comprising

a number of sieving members situated after the at least one process container, the number of sieving members separating an at least partly enriched solid phase from an at least partly diluted aqueous phase, and accumulating the at least partly enriched solid phase at the upper face of the sieving member, and said plant furthermore comprising

means for distributing an at least partly purified first aqueous phase after traversing the sieving member to a first collection container and means for distributing the at least partly enriched solid phase to a deposition container,

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method of treatment of an organic waste material containing a solid phase and an aqueous phase. Particularly, the method is useful for separation and purification of an organic waste material, such as manure from livestock production. By separating and purifying the organic waste material the constituents of the organic waste material are fractionated, which in some circumstances gives better opportunities of utilising or getting rid of the organic waste material.

Especially, purification of nutrients, such as nitrogen, potassium or phosphor, is of particular interest according to the present invention. Separation of organic material contained in the organic waste material may be of similar interest according to the present invention. Of particular interest in the present invention is manure from livestock production being separated into a solid phase containing organic material and nutrients, and a purified aqueous phase.

In a first method the organic waste material containing a solid phase and an aqueous phase is treated in two steps, resulting in an at least partly enriched solid phase and an at least partly diluted aqueous phase. The at least partly enriched solid phase and the at least partly diluted aqueous phase are obtained by a processing step and a separation step.

The term "waste" in relation to organic material should be very broad interpreted in the present invention, meaning organic material that is left after any kind of treatment, leaving a part of organic material that could more beneficially be processed in way of the process in the present invention. Preferably, the organic waste material is manure from livestock production. According to the present invention the organic waste material may also originate be wastewater, industrial water, institutional water, water from households, water from fishing industries, water from manufacturing industries and water from processing industries. Other sources of organic waste material are of cause present, and a person skilled in the art is aware of such sources, which may enter the present invention.

The meaning of the wording "solid phase and aqueous phase" is to give the reader the understanding that the organic waste material contains both an aqueous phase an a certain amount of solid material being referred to as the "solid phase". The solid phase is essentially organic material, but may contain a certain amount of other substances, such as naturally occurring nutrients and inorganic compounds. When using the word "essentially" this is to underline that the main fraction of the organic waste material is constituted of organic material. The organic material is often referred to as "dry matter" in the present invention corresponding to the solid phase.

In one presently preferred embodiment of the present invention the dry matter content of the organic waste material is below 20% wt, such as between 10-20% wt, alternatively between 3-10% wt. If at least 20% wt of an organic waste material is dry matter the organic waste material may preferably be supplied with liquid to be used in the present invention.

In the first method the organic waste material containing a solid phase and an aqueous phase is treated in two steps, resulting in an at least partly enriched solid phase and an at least partly diluted aqueous phase. The enriched solid phase and the diluted aqueous phase are obtained by a processing step and a separation step.

In particular, the processing step (a) comprises the following:

optionally, subjecting the organic waste material to at least one coagulant, thereby precipitating at least 90% wt. of the phosphor ions and initiating flocculation of the solid phase and thus excluding at least part of the anions from the aqueous phase,

allowing at least part of the cations of the organic waste material to associate to negatively charged solid materiel, thereby excluding at least part of the cations from the aqueous phase, and

introducing at least one flocculating agent, thereby obtaining an at least partly diluted aqueous phase and an at least partly enriched solid phase; and The intention of having a processing step is to allow the organic waste material to interact with extern as well as sources contained in the organic waste material prior to separation. The interaction may alter the physical as well as the chemical properties of the organic waste material, which may be necessary for the later separation step to function properly.

It should be understood that "interactions" in the present invention could be any "occurrence" taking place between the organic waste material and extern sources as well as sources contained in the organic waste material itself. These interactions may be adsorption, absorption, flocculation, sedimentation, floating, chemical reactions, non- chemical reactions or any combination thereof. The list is not complete, but this should not exclude other interactions from taking place in the present invention.

In the present invention it is though presently preferred to introduce and subject the organic waste material to at least one coagulant, at least one flocculating agent and to allow association between negatively charged solid material and cations of the organic waste material.

These interactions may take place in any stage of the processing step, understood in the sense that one of the at least one coagulant, the at least one flocculating agent and the negatively charged solid material may be the first to interact with the organic waste material. Actually, the order of interactions may be randomly, starting with any of the mentioned interactions, followed by any of the mentioned interactions and ended with any of the interactions mentioned. This randomness furthermore allows all the interactions to occur simultaneously, in a simultaneously couple of two or in a simultaneous couple of two or three with any other agent suitable for the processing step. If more than one coagulant, one flocculating agent or one negatively charged material is present, these consequently may interact randomly as well.

In one presently preferred embodiment the at least one coagulant is introduced first and the at least one flocculating agent is introduced in the end of the processing step. The association between negatively charged solid material and cations of the organic waste material is in one preferred embodiment occurring during the whole processing step.

Turning to the specific interactions in the processing step, the subjecting of organic waste material to at least one coagulant allows precipitation of at least 90% wt. of the phosphor ions and initiates flocculating of the solid phase and thus excluding at least part of the anions from the aqueous phase. Phosphor may be present as dihydrogen phosphate and hydrogen phosphate. The coagulant may be any agent capable of performing the above mentioned interactions or any agent capable of performing at least a part of these interactions, in this case accompanied by an additional agent or agents capable of performing at least the other part or parts of the interactions.

In one presently preferred embodiment the at least one coagulant may be positively charged or negatively charged poly-electrolytes, such as positively charged polymers. The poly-electrolytes may in a presently preferred embodiment be a high molecular organic polymer. More than one poly-electrolyte may be used according to the invention.

In another embodiment the at least one coagulant may be a metal or salts thereof. The metal may be iron, aluminium, magnesium, etc, or any salts thereof, in any oxidation stage. Fe (III) is preferred for the potential of precipitating phosphor ions. Other agent capable of precipitating phosphor ions may be applied, such as calcium. Additionally, the term "coagulant" should be understood as an agent to initiate flocculation of the solid phase of the organic waste material and thus may involve flocculating agents being obvious for a person skilled in the art. When using more than more coagulant in the present invention, it should be clear that any combination for such use can be applied.

The precipitation of phosphor ions is a main feature in the present invention. By adding iron (III) sulphate to the manure, the phosphorus compounds will precipitate as sparingly soluble iron phosphates. The goal is of cause to remove as lot of the phosphor ions from the aqueous phase as possible. In one preferred embodiment at least 90% wt. of the phosphor ions is precipitated during the processing step, more preferred 95% wt. of the phosphor ions is precipitated in the processing step, most preferred 99% wt. of the phosphor is precipitated in the processing step.

Phosphor may be present as ions or bound in organic material, thus when precipitating the phosphor ions in the present invention it should be understood that phosphor may be contained in the organic material. The phosphor contained in the organic material is later removed in the separation process. A high degree of precipitation not necessarily is an expression of the purification phosphor from the aqueous phase of the organic waste material. Part of the organic bound phosphor may additionally be precipitated during the processing step, and this will be preferred unless the content of organic bound phosphor is so high that this may influence the performance of the present invention. In that case the precipitation of organic bound phosphor should be prevented. In the following the precipitation of phosphor simply is referred to as precipitation of phosphor ions. The consequence of the precipitation of phosphor ions is that at least part of the anions is excluded from the aqueous phase. "At least part of the anions" in this sense refers to a situation where other ions than phosphor ions are removed from the aqueous phase of the organic waste material. In one embodiment it is preferred to remove anions other than phosphor ions from the aqueous phase.

Turning to the next specific interaction in the processing step, at least part of the cations of the organic waste material is allowed to associate to negatively charged solid materiel, thereby excluding at least part of the cations from the aqueous phase.

When using the word "allowing" it should be interpreted as either letting or assisting the at least part of the cations of the organic waste to associate to negatively charged solid material. A combination may also be a possibility. It is presently preferred that the cations associate without assistance, in this sense "letting", but it may be necessary to assist and should not limit the scope of the invention. Assistance could involve mixing of the organic waste material, heating of the organic waste material, keeping back the organic waste material in a suitable way, or in another way make the contact between the cations contained in the organic waste material and the negatively charged solid material as suitable as possible, or a combination thereof. Prolonging the flow distance in the processing step or the residence time of the organic waste material may additionally be a possibility.

Associating the at least part of the cations of the organic waste material to the negatively charged solid material means that the cations are adsorbed to material with opposite charge or in another way is forming a complex with negatively charged solid material.

"Associating" thus may be any form of physical coupling between the cations of the organic waste material and negatively charged solid material, thus being enabled by electrostatic forces. It should be noticed that the adsorption of the cations may be to non-charged solid material as well. Though this adsorption is thought to be of minor interest it may contribute to the association of cations.

Electrostatic coupling between the cations and the negatively charged solid material require a substantial amount of negative charged solid material. If for instance a huge amount of cations are present in the organic waste material there may not be sufficient negatively charged solid material present in the organic waste material to couple there cations electro-statically. The solid phase of the organic waste material namely usually contains both positively and negatively charged solid materials. The negatively charged solid material present in the organic waste material thus potentially are adequate to exclude at least a part of the cations from the aqueous phase. In one embodiment negatively charged solid material is contained in the organic waste material, and thus may not be added to the organic waste material. In another embodiment the negatively charged solid material is added to the organic waste material. Depending on the potential of the negatively charged solid material present in the organic waste material, additionally negatively charged solid material may be added to the organic waste material.

In a presently preferred embodiment negatively charged solid material is additionally added to the organic waste material. This addition heavily enhances the electrostatic coupling and thus the association of cations.

Negatively charged solid material added to the organic waste material may be negatively charged material of organic or non-organic origin. Thus, the negatively charged solid material may be any organic material suited for the present invention, such as pre- manufactured negatively charged organic material and natural organic material involving sphagnum. The negatively charged solid material may also be any negatively charged non- organic material suited for the present invention, such as colloids and minerals including aluminosilicate minerals or both. It should be understood that more than one sort of negatively charged solid material can be applied according to the invention, and that any combination may be applied. In a particular preferred embodiment minerals are used, preferable minerals such as zeolite and bentonite.

Among cations present in the organic waste material, ions of nitrogen and ions of potassium are of particular interest in the present invention. Other ions contained in the organic waste material potentially is of similar interest and should according to the electrostatic forces be excluded form the aqueous phase as well as the cations of special interest. The cations may further be cadmium, copper, zinc, and toxicological injurious compounds, and any combination and derivatives thereof. Some cations may however not be electrostatically coupled being mainly cations with too high charge for a coupling to occur.

Of special interest is ammonium, which in many instances is of significant importance. Ammonium is the ionised form of ammonia. In some circumstances it is preferred to carry out the invention with as much of the ammonia in the ionised form. In other circumstances it might be a disadvantage with a high content of ammonia in ionised form. There exists a chemical equilibrium between ammonia and ammonium dependent on the pH value. With a pKa value around 7, a pH value below 7 results in more ammonium than ammonia and a pH above 7 results in more ammonia than ammonium. Thus, the lower the pH value the higher content of ammonium.

In a presently preferred embodiment the pH value of the organic waste material is at the most 6.5, meaning that a higher content of ammonium than ammonia is present in the organic waste material. The content of associated negatively charged solid material is accordingly higher, which means that the purification of the aqueous phase may be higher, thereby excluding a greater part of the cations from the aqueous phase. Thus, when referring to a "least a part" of the cations excluded form the aqueous phase, this implies that a high pH value only associate a minor fraction of the ammonia, whereas a low pH value associate a high fraction of the ammonia. According to this aspect it is preferred that the pH value lies between 3.0 to 6.5, preferably between 3.0 to 6, more preferably between 5.0 to 6.0, most preferably around 5.5. An additionally advantage of having a pH value in this range is the prevention of possible microbiological contamination, which should be limited if the pH value is vary low.

Turning to the specific interactions in the processing step, at least one flocculating agent is introduced, thereby obtaining an at least partly diluted aqueous phase and an at least partly enriched solid phase.

The introduction of at least one flocculating agent flocculates the solid phase of the organic waste material, including organic material, phosphates, ions of nitrogen, ions of potassium and minerals, thereby obtaining an at least partly diluted aqueous phase and an at least partly enriched solid phase. "At least partly diluted" and "at least partly enriched" means that the ions and organic material to some degree has been excluded from the aqueous phase being transferred to the solid phase, now enriched in both organic material and nutrients. The addition of at least one flocculating agent further makes the enriched solid phase accumulated in the separation step easier for the aqueous phase to penetrate, which is of potential interest.

The flocculating agent may be positively charged or negatively charged poly-electrolytes. In the present invention though, the flocculating agent is a positively charged poly- electrolyte, such as a high molecular organic polymer. More than one poly-electrolyte may be used according to the invention.

In particular, the separation step (b) of the first method comprises the following:

separating the at least partly enriched solid phase obtained in step (a) from the at least partly diluted aqueous phase using a number of sieving members accumulating the at least partly enriched solid phase at the upper surface of the number of sieving members, thus in a controlled manner allowing the at least partly diluted aqueous phase to traverse both the at least partly enriched solid phase and the number of sieving members, thereby letting at least part of the cations associate to negatively charged solid materiel, obtaining an at least partly purified first aqueous phase containing at the most 30% wt. of the nitrogen, at the most 40% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

After the organic waste material has been treated in the processing step, the at least partly enriched solid phase is separated from the at least partly diluted aqueous phase using a number of sieving members. When using the term "sieving member" this may include any physical member capable of separating the solid phase from the aqueous phase. The "number of sieving members" may be filters, sieves, and wires used for sieving, wire netting, constructions provided with substantially small masks, filter cloths or any variations thereof, or any combination thereof.

More than one sieving member may be used if appropriate. The use of more than one sieving member are thought to be useful if one sieving member is not enough for proper separation. The sieving members thus may be arranged in series, finally preventing organic material to pass through. A possibility is to provide the sieving members with masks of different size allowing different sizes of organic material to pass through. This may be an advantage if the organic material preferably should be of different particulate size. If the masks are getting smaller as the separation proceeds this may also be an advantage for the separation step. Alternatively, if there is more than one sieving member, these may be used in parallel, meaning that the organic waste material is only separated by one sieving member, but more than one sieving member helping the separation process. Again the masks could be of different size, thus being an advantage if the organic material should be sorted.

In one presently preferred embodiment the sieving member has a mask size of around 2mm, but it should be understood that another mask size potentially is of similar interest. Furthermore, a filter cloth is provided in one presently preferred embodiment of the invention. The filter cloth has smaller masks than the sieving member and thus preferably is associated to the sieving member facing the enriched organic material.

The main function of the number of sieving members obviously is to separate the at least partly enriched solid phase from the at least partly diluted aqueous phase, and thereby accumulating the at least partly enriched solid phase at the upper surface of the number of sieving members.

The "upper surface" of the sieving member should be interpreted as the surface pointing towards the at least partly enriched solid phase. If the sieving members are situated horizontally the meaning of "above" is obvious, the sieving members may also be situated in any angle to the horizontally line, including a vertically arrangement of sieving members, and in this case "above" is understood as an accumulation of the at least partly enriched solid material at the surface of the sieving member pointing towards the at least partly enriched solid phase.

Accumulation of the solid phase at the upper surface of the sieving member may in the present invention proceed until the aqueous phase either are prevented from traverse the accumulated at least partly enriched solid phase due to the thickness of at least partly enriched solid phase. In the present invention at least partly enriched solid phase simply refers to the at least partly enriched solid phase. The at least partly enriched solid phase may alternatively be partly or completely removed from the upper surface of the number of sieving members of practical reasons or functional reasons.

In one presently preferred embodiment of the invention, the at least partly enriched solid phase is regularly removed from the upper surface of the number of sieving members. Pumping of at least part of solid material may do this removal. It is preferred that some solid material is left after pumping, so that the aqueous phase may traverse both at least part of the solid material and the number of sieving members. Alternatively, the at least partly enriched solid phase may be removed by way of a mechanic movement, such as a continuously and/or periodically physical removal by a rotor and/or continuously and/or periodically removal by a conveyer band/belt. In another embodiment the at least partly enriched solid phase is removed by tilting the number of sieving members, or in another way turning the number of sieving members away from the situated angle.

One of the main issues to be dealt with running the sieving members is to control the accumulation of the at least partly enriched solid phase, thus in a controlled manner allowing the at least partly diluted aqueous phase to traverse both the at least partly enriched solid phase and the number of sieving members. "Controlled manner" should be broadly interpreted, meaning any way of letting or assist the aqueous to traverse the at least partly enriched solid material. The aqueous may traverse the at least partly enriched solid phase and sieving member solely by gravity, alternatively by pressure assistance or any other assistance. In one preferred embodiment of the invention, the aqueous phase is assisted to traverse the at least partly enriched solid phase and the number of sieving members by vacuum and the addition of alumino-silicates.

The intention of "controlling" the traversing of the at least partly diluted aqueous phase through both the at least partly enriched solid phase and the number of sieving members is mainly to let at least part of the cations associate to negatively charged solid materiel.

The contact between the at least partly enriched solid phase and the cations present in the organic waste material is of great importance for proper purification. By "controlling" the separation it is possible to regulate the association of cations to negatively solid material. This may be of great importance if a certain purification percent is required and the association of the cations should be high. The degree of association normally is correlated to the degree of contact between the cations and the negatively charged sold material. Thus, if the contact should be intensified, the contact time or the interaction time should be high.

One way to optimise the contact time is to regulate the pressure assisting the aqueous phase to traverse the at least partly enriched solid phase, and this "control" may in one embodiment be preferred. Another presently preferred embodiment is to re-circulate the at least partly purified first aqueous phase obtained after the at least partly purified aqueous phase has traversed the at least partly enriched solid phase. If the at least partly purified first aqueous phase is not purified to a preferred degree, it may thus be re-circulated to the at least partly enriched solid phase. This re-circulated phase may be re-circulated to the upper surface of the at least partly enriched solid phase, or at the upper surface of the number of sieving members, or in any position between the number of sieving members and the upper surface of the at least partly enriched solid phase. Preferably though, the re-circulated phase is transferred to the upper surface of the at least partly enriched solid phase, allowing the re-circulated phase to traverse the at least partly enriched solid phase. The re-circulation may be done more than once.

The at least partly purified first aqueous phase obtained after the at least partly purified aqueous phase has traversed the at least partly enriched solid phase and the number of sieving members contains at the most 30% wt. of the nitrogen, at the most 40% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material. In many circumstances this purification is adequate in respect of regulations for purification of organic waste material, and thus this degree of purification is preferred. Thus, in one presently preferred embodiment the at least partly purified first aqueous phase contains at the most 30% wt. of the nitrogen, more preferably 20% wt. of the nitrogen, most preferably at the most 10% wt. of the nitrogen present in the organic waste material. A higher degree of purification is further preferred.

Further, in one presently preferred embodiment the at least partly purified first aqueous phase contains at the most 40% wt. of the potassium, more preferably 20% wt. of the potassium, most preferably at the most 10% wt. of the potassium present in the organic waste material. A higher degree of purification is further preferred.

In a still further presently preferred embodiment the at least partly purified first aqueous phase contains at the most 1% wt. of the phosphor, more preferably 0.1% wt. of the phosphor, most preferably at the most 0.01% wt. of the phosphor present in the organic waste material. A higher degree of purification is further preferred.

It should be understood that the purification of nitrogen, potassium and phosphor includes the ions of the nutrients and the organic bound content of the nutrients. It should also be understood that the organic waste material in some circumstances may be added liquid to enhance the purification, preferably with the aqueous phase of treated organic waste material.

Sometimes the purification is still not adequate and in this instance, the first method of treatment of organic waste material described above is supported with a further step of purification. This further step of purification may additionally in combination with the first method constitute a second method of treatment of organic waste material containing a solid phase and an aqueous phase. For reasons of simplicity this further step in the first method and the further step in combination with the first method constituting the second method is described together below.

In particular, the further step of treatment of an organic waste material containing a solid phase and an aqueous phase comprises the following:

(c) transferring the at least partly purified first aqueous phase obtained in step (b) to one or more reverse osmosis unit(s) separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the reverse osmosis unit(s), so that the at least partly purified first aqueous phase traversing the reverse osmosis unit(s) is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material, or transferring the at least partly purified first aqueous phase obtained in step (b) to one or more sub-filtration unit(s) such as nano-filtration separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the nano-filtration unit(s), so that the at least partly purified first aqueous phase traversing the sub- filtration unit(s), preferably the nano-filtration unit(s), is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

One or more further purification steps may be needed according to the present invention, further purifying the at least partly purified first aqueous phase to obtain an at least partly purified second aqueous phase. The one or more further steps of purification may involve purification treatment processes selected from the group consisting of micro-filtration (MF), ultra-filtration (UF), nano-filtration (NF), reverse osmosis (RO), electro-dialysis, electro-deionization, pervaporation, membrane extraction, membrane distillation, membrane stripping, membrane aeration, and other processes such as irradiation.

Membrane separation, which uses a selective membrane, is a fairly recent addition to the industrial separation technology for processing of liquid streams, such as water purification, and is presently preferred according to the invention in order to purify the at least partly purified first aqueous phase to obtain an at least partly purified second aqueous phase. In membrane separation, constituents of the influent typically pass through the membrane as a result of a driving force(s) in one effluent stream, thus leaving behind some portion of the original constituents in a second stream. The driving force of the separation depends on the type of the membrane separation. Pressure-driven membrane filtration, also known as membrane filtration, includes micro-filtration, ultra- filtration, nano-filtration and reverse osmosis, and uses pressure as the driving force, whereas the electrical driving force is used in electro-dialysis and electro-deionization. Historically, membrane separation processes or systems were not considered cost effective for water treatment due to the adverse impacts that membrane scaling, membrane fouling, membrane degradation and the like had on the efficiency of removing solutes from aqueous water streams. However, advancements in technology have now made membrane separation a more commercially viable technology for treating aqueous feed streams suitable for use in industrial processes.

It may be an advantage to apply several of the further purification steps according to the invention, including one or more of the purification treatments mentioned above, in any number and in any order. In one presently preferred embodiment, it may be an advantage to circulate the at least partly purified first aqueous phase one, more or several times in order to obtain the desired purification degree of the at least partly purified second aqueous phase. For the purpose of some applications, the further purification step(s) may be used in order to obtain an at least partly purified second aqueous phase used for drinking or similar applications, such as applications in which the water is to have a certain degree of purity for the particular purpose.

In one presently preferred embodiment of the invention, the at least partly purified first aqueous phase is transferred to one or more nano-filtration units. Nano-filtration is a relatively new pressure-driven membrane filtration process, falling between reverse osmosis and ultra-filtration. The nano-filtration may be carried out at a pressure of 10 to 50 bar, preferably 15 to 35 bar. Nano-filtration typically retains large and organic molecules with a molar mass greater than 300 g/mol. The nano-filtration is typically carried out with a flux of 10 to 100 l/m.sup.2h. The most important nano-filtration membranes are composite membranes made by interfacial polymerisation. Polyether sulfone membranes, sulfonated polyether sulfone membranes, polyester membranes, polysulfone membranes, aromatic polyamide membranes, polyvinyl alcohol membranes and polypiperazine membranes are examples of widely used nano-filtration membranes and may be used according to the present invention. Inorganic and ceramic membranes may also be used for nano-filtration.

The polymeric or inorganic membranes according to the present invention typically have a cut-off size of 100-2500 g/mol, preferably 150 to 1000 g/mol, most preferably 150 to 500 g/mol. The nano-filtration membranes, which are useful in the present invention may have a negative or positive charge. The membranes may be ionic membranes, i.e. they may contain cationic or anionic groups, but even neutral membranes are useful. The nano- filtration membranes may be selected from hydrophobic and hydrophilic membranes. The typical form of nano-filtration membranes is a flat sheet form. The membrane configuration may also be selected e.g. from tubes, spiral membranes and hollow fibers. "High shear" membranes, such as vibrating membranes and rotating membranes can also be used.

The further step of nano-filtration may also comprise one or more pre-treatment steps. The pre-treatment before the nano-filtration is typically selected from ion exchange, ultra- filtration, chromatography, concentration, pH adjustment, filtration, dilution and combinations thereof. Before the nano-filtration, the at least partly purified first aqueous phase is thus in one embodiment pre-treated by ultra-filtration or chromatography, for example. Furthermore, a pre-filtering step to remove the solid substances can be used before the nano-filtration. The pre-treatment of the at least partly purified first aqueous phase may also comprise concentration, e.g. by evaporation, and neutralisation.

In another presently preferred embodiment of the present invention, the at least partly purified first aqueous phase is transferred to one or more reverse osmosis units. Ion removal may be conducted using thermal methods, involving distillation, or by chemical methods, for instance by precipitating the hardness ions in apparatus from which the solid may easily be removed. In another class of processes, ions may be removed in methods involving semi-permeable membranes or ion exchange resins. Processes involving membranes include reverse osmosis and electro-osmosis, each using semi-permeable membranes. Processes involving ion exchange resins involve passage of water over resin particles, fibres or sheets formed of ionomers having exchangeable counter-ions. Multivalent hardness ions may be exchanged with monovalent anions and cations or multi- or mono-valent ions may be exchanged for hydrogen ions and hydroxyl ions for complete de-ionisation. The ion exchange resins are regenerated periodically and reused.

In general osmosis is the process whereby water moves across a semi-permeable membrane separating aqueous solutions of dissimilar TDS (Total Dissolved Solids) concentrations to achieve a balance in the chemical potential of the water on either side of the semi-permeable membrane. Because the chemical potential of the water includes the pressure head, the osmosis phenomenon is demonstrated, and quantification of the osmotic potential or osmotic pressure of a solution is made, simply by allowing the heights of two columns of two aqueous solutions containing dissimilar TDS concentrations and connected through a semi-permeable membrane, to come to equilibrium and measuring the difference in heights of the solution columns at equilibrium. In reaching this osmotic equilibrium, water moves from the column containing the aqueous solution with the lower TDS concentration to that containing the higher until the chemical potentials of the water in each column are equal.

In Reverse Osmosis (RO), pressure is applied to the aqueous solution containing the higher TDS concentration, thus increasing the chemical potential of the water in that solution, and causing water to move in the reverse direction across the semi-permeable membrane. This process produces water of a lower TDS concentration. The RO process is used commercially to remove water of a lower TDS concentration from an aqueous solution containing a higher TDS concentration. Stated in lay terms, but incorrectly in terms of actual process, RO is used to remove TDS from water, or to "desalinate" the water.

Commercial RO units range in size from small enough to fit under the sink of a household kitchen and supply water containing lower TDS to the household, to large enough to supply water of lower TDS to a large city. Commercial RO units have found wide application from desalinating seawater, to desalinating brackish water, to removing the chemical components causing hardness in water, a process known as "membrane softening".

An RO unit may consist of a module containing the RO membrane, enclosed by a housing. The housing withstands the applied pressure on the feed solution (water to be desalinated), and has plumbing which directs the feed solution properly through the module, and directs the reject solution or retentate (salt-enriched water) and the permeate (desalted water or product) to exit ports on the housing in such fashion that the solutions do not mix.

A typical membrane may comprise a polypropylene fiber support sheet covered by a porous poly-sulfone, which further comprises a cast layer (for example, but not limited to, approximately 0.1 to approximately 1 .mu.m) of a polyamide. Of course, membranes are not limited to materials comprising polypropylene, poly-sulfone, and/or polyamide because other materials, e.g., metal, ceramic, etc., are known in the art of filtration. In a typical membrane, polyamide forms an active membrane surface, or membrane layer, i.e., the layer that is primarily or solely responsible for rejecting TDS from a feed solution and for allowing passage of permeate. In general, at least one other membrane layer is present for physical support of the active layer. Of course, depending on particular use, the "support" layer optionally comprises other functions. For example, but not limited to, a catalytic support layer or support layer for other useful material.

In another embodiment the at least partly purified first aqueous phase is treated in one or more ultra filtration units.

In another embodiment the at least partly purified first aqueous phase is transferred to one or more charcoal units. Activated carbons include those derived from natural wood sources such as coconut shell-origin activated carbon and charcoal-origin activated carbon, and are often in powder or granular form. From the past, they have long been utilized in the organic chemistry field for purification, de-colouring and removal of trace ingredients. The application of activated carbon to the electronic industry was recently reported as disclosed in JP-A 8-12602. There are also known coal-origin activated carbons, such as those derived from coal and tar. Recently, activated carbon in fibrous form is available. It is reported that a certain activated carbon exerts a specific function depending on its shape and its composition or microstructure which will be inherent to its origin, and is used in a particular application requiring such a function.

In another embodiment the at least partly purified first aqueous phase is transferred to one or more flying ash units, where the ions of particular interest according to the invention are adsorbed. Fly ash is essentially fine solid non-combustible mineral residue typically resulting from coal-burning operations and may be added one or more positively charged or negatively charged poly-electrolytes, such as positively charged polymers of preferably high molecular weight. It does not however include other more coarse combustion by-products such as bottom ash, cinders, or slag. Fly ash typically comprises very fine particles, usually containing silica (SiO.sub.2), alumina (Al.sub.2 O.sub.3), ferric oxide (Fe.sub.2 O.sub.3), calcium oxides (CaO), and small quantities of other oxides and alkalies. Fly ash is an artificial possolan and is generally not cementious in itself, but with the presence of water and lime compounds, it forms a cementious product. These lime compounds often exist naturally in the fly ash or can be supplied by the addition of a lime source such as cement or kiln dusts.

In yet another embodiment the at least partly purified first aqueous phase obtained in step (b) is transferred to one or more positively charged resins containing at least divalent positively charged ions, the one or more positively charged resins repelling the cations, thereby at least partly preventing the cations to traverse the one or more positively charged resins, so that the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

Subjecting the at least partly purified first aqueous phase to one or more positively charged resins further purifies the aqueous phase, thus allowing a higher degree of purification. By subjection to the one or more positively charged resins the cations are repelled, thereby at least partly preventing the cations to traverse the one or more positively charged resins. Thus, the function of this step is essentially "reverse ion exchanging". A traditional ion exchanger adsorbs the ions with opposite charge, whereas the present reverse ion exchanger repels the ions of similar charge.

The at least partly purified first aqueous phase is preferably transferred to the top of a column containing the one or more positively charged resins. When the aqueous phase reach the resins, the cations of the aqueous phase is kept back due to electrostatic similar charge of the resins. Accordingly, the cations will concentrate in the aqueous phase above the resins, and the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified.

The resins may be any solid material having a positive charge. The solid material may be pellets with a suitable porosity for the aqueous phase to traverse. Preferably, the pellets are made of plastic, impregnated with at least trivalent positively charged ions, such as aluminium and salts thereof. The pellets may comprise divalent positively charged ions as well, but trivalent positively charged ions presently seems to be the most suitable due to the fact that these ions, especially aluminium, is harder to wash out. Aluminium is strongly bound to the pellets. The positively charged ions may be impregnated as mentioned, but may also be associated to the resins in other ways, this will not limit the scope of the present invention. The ions may additionally be contained in the resins. In the present invention more than one resin may be more suitable for carrying out the method.

The aqueous phase at the top of the resins may in a presently preferred embodiment be renewed to allow a better purification. In one preferred embodiment the aqueous phase at the top of the resins is re-circulated to the sieving members or to the single processes prior to separation or a combination thereof. The fraction may also be used or discarded in another way.

Finally, an at least partly purified second aqueous phase is obtained containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material. Preferably, the at least partly purified second aqueous phase contains at the most 5% wt. of the nitrogen, at the most 5% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material. More preferably, the at least partly purified second aqueous phase contains at the most 2% wt. of the nitrogen, at the most 2% wt. of the potassium and at the most 0.1% wt. of the phosphor present in the organic waste material.

The purification step using one or more positively charged resins mentioned above according to the invention also may constitute a separate method. The third method essentially comprises:

subjecting an at least partly purified first aqueous phase of organic waste material to one or more positively charged resins containing at least divalent positively charged ions, the one or more positively charged resins repelling the cations, thereby at least partly preventing the cations to traverse the one or more positively charged resins, so that the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

This third method allows the purification of an at least partly purified first aqueous phase of organic waste material and thus may be an independent method. If for instance the organic waste material is essentially devoid of organic material this third method may be applied independent of the previous steps in the first and second method.

Another purification step may be needed according to the present invention, further purifying the aqueous phase. This step involves purification with ion exchange. The at least partly purified second aqueous phase is transferred to one or more negatively charged resins containing anions, whereby one or more negatively charged resins adsorbs the cations still present in the aqueous phase. In another embodiment the resins may be allowed to be positive, as long as the ion strength is strong enough to associate the cations of interest. Thus, by "negative" in this context is meant an ion strength that is strong enough to associate the cations of interest. This purification step at least partly prevents the cations to traverse the one or more negatively charged resins, which leads to an at least partly purified third aqueous phase.

The purification by the further step of purification implies that the at least partly purified third aqueous phase contains at the most 1% wt. of the nitrogen, at the most 1% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material. Preferably, the at least partly purified third aqueous phase contains at the most 0.5% wt. of the nitrogen, at the most 0.5% wt. of the potassium and at the most 0.1% wt. of the phosphor present in the organic waste material. The resins are commercially used resins, and may include all kinds of known resins, which a person skilled in the art will regard as suitable in the present invention.

Furthermore, there is provided a plant suitable for the methods according to the invention comprising:

means for introducing the organic waste material to at least one process container, and said plant furthermore comprising

supply means for dosage of negatively charged solid materiel from a number of supply containers containing negatively charged solid material and

supply means for dosage of at least one flocculating agent from a number of flocculating agent supply containers, and said plant furthermore comprising a number of sieving members situated after the at least one process container, the number of sieving members separating an at least partly enriched solid phase from an at least partly diluted aqueous phase, and accumulating the at least partly enriched solid phase at the upper face of the number of sieving members, and said plant furthermore comprising

means for distributing an at least partly purified first aqueous phase after traversing the number of sieving members to a first collection container and means for distributing the at least partly enriched solid phase to a deposition container,

Some of these elements are already described in the section relating to the method according to the invention and thus are not mentioned in further detail.

The plant may advantageously comprise some further elements according to the invention if appropriate.

Optionally, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more positively charged resins containing at least divalent positively charged ions and a second collection container for collecting an at least partly purified second aqueous phase traversing the one or more positively charged resins.

The plant may advantageously comprise some further units according to the invention if appropriate, including but not limited to units for ion exchange, micro-filtration (MF), ultra- filtration (UF), nano-filtration (NF), reverse osmosis (RO), electro-dialysis, electro- deionization, pervaporation, membrane extraction, membrane distillation, membrane stripping, membrane aeration, and other processes such as irradiation.

In a presently preferred optional set-up, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more nano-filtration units and a second collection container for collecting an at least partly purified second aqueous phase traversing the nano-filtration units.

In a another presently preferred optional set-up, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more reverse osmosis units and a second collection container for collecting an at least partly purified second aqueous phase traversing the reverse osmosis units.

In another optional set-up, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more flying ash units and a second collection container for collecting an at least partly purified second aqueous phase traversing the flying ash units.

In another optional set-up, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more ultra-filtration units and a second collection container for collecting an at least partly purified second aqueous phase traversing the ultra-filtration units.

In another optional set-up, the plant comprises means for distributing the at least partly purified first aqueous phase to one or more charcoal units and a second collection container for collecting an at least partly purified second aqueous phase traversing the charcoal units.

In another embodiment, the plant comprises or further comprises means for distributing the at least partly purified second aqueous phase to one or more negatively charged resins containing anions and a third collection container for collecting an at least partly purified third aqueous phase traversing the one or more negatively charged resins.

If appropriate the collected at least partly purified first aqueous phase is re-circulated to the upper surface of the number of sieving members. Thus, means for re-circulating is provided. The plant additionally further comprises means for re-circulating the collected at least partly purified second aqueous phase to the upper surface of the number of sieving members and means for re-circulating the collected at least partly purified third aqueous phase to the upper surface of the number of sieving members. The means for re- circulating preferably is capable of distributing the collected at least partly purified aqueous phase to the upper surface of the at least partly enriched solid phase accumulated at the upper surface of the number of sieving members. The means may be a dosage pump being situated between the supply container containing the supply media and the process container for the organic waste material.

The coagulant supply containers are preferably connected to at least one separate first process container, the one or more supply containers containing negatively charged solid material are preferably connected to at least one separate second process container and the one or more flocculating agents supply containers are preferably connected to at least one separate third process container. The process containers are in a particularly preferred embodiment arranged starting with the at least one separate first process container, then the at least one separate second process container and finally the at least one separate third process container. The separate process containers are most preferably located in one housing, preferably within a rectangular housing. In one presently preferred embodiment in which the separate process containers are located in one housing they are arranged horizontally starting with the at least one separate first process container at one side, then the at least one separate second process container at the middle and finally the at least one separate third process container at other side. In a more preferred embodiment, the horizontally arranged separate containers are separated by plates, wherein the plates preferably are provided with at least one opening. In a still more preferred embodiment the openings are situated at the top of the housing of a substantially rectangular shape, and the organic waste material preferably is intended for being passed through the holes of the plates by means of gravity.

In another embodiment in which the separate process containers are located in one housing they are arranged vertically starting with the at least one separate first process container at the top, then the at least one separate second process container at the middle and finally the at least one separate third process container at the bottom. In a more preferred embodiment, the vertically arranged separate containers are separated by plates, wherein the plates preferably are provided with at least one opening. In a still more preferred embodiment the openings are situated in diagonally opposite corners of the plates of a substantially rectangular shape, and the organic waste material preferably is intended for being passed through the holes of the plates by means of gravity.

BRIEF DECRIPTION OF THE DRAWING

The invention will hereafter be described according to a plant with reference to the figures. The description should solely be seen as a description of possible plants, which should not limit the scope of the invention.

Fig. 1 is a process diagram illustrating the different elements in possible plant for treatment of organic waste material according to the invention, fig. 2 is a process diagram illustrating the different elements in a possible first alternative plant for treatment of organic waste material according to the invention, fig. 3 is a process diagram illustrating the different elements in a possible second alternative plant for treatment of organic waste material according to the invention, fig. 4 is a schematic drawing of separation of organic waste material and re-circulation of an at least partly purified first aqueous phase obtained after the separation, fig. 5 is a schematic drawing of a preferred arrangement of process containers for the treatment of organic waste material prior to separation, and fig. 6 is a schematic drawing of a process for purifying an at least partly purified first aqueous phase into an at least partly second purified aqueous phase using treatment with a number of at least divalent positively charged resins.

Fig. 1 illustrates a process diagram for carrying out a possible and preferred process according to the invention. Reference numbers 1-4 shows process containers, wherein organic waste material is treated prior to separation. The number of process containers is limited in this example, and it should be understood that fewer or more containers may be provided. In a first process container 1, at least one coagulant is introduced. The coagulant process container 1 is preferably equipped with a stirrer (not shown). In another process container 2, negatively charged solid material is added. It is optional to add the negatively charged solid material, but it is preferred. The process container 2 for the optional addition of negatively charged solid material is also preferably equipped with a stirrer (not shown). The addition of negatively charged solid material is preferably controlled proportional to an inlet flow of the organic waste material. The size of the container 2 is preferably dimensioned to allow for a mixing time of just 10 minutes. In an alternative embodiment, only one container constitutes the vessel in stead of all four or more containers 1-4.

When turning to process containers 3 and 4, both containers are suited for addition of a flocculating agent. One container is preferred, but more than one container, as shown, may be used. The containers are preferably equipped with a stirrer (not shown). The addition of the flocculating agent is preferably controlled proportional to the inlet flow of the organic waste material. The size of the container is preferably dimensioned to allow for a mixing time of just 10 minutes. In an alternative embodiment, only one container constitutes the vessel in stead of all four or more containers 1-4.

Fig. 1 further shows that the process containers 1-4 may be built together in one housing 4a, where the four process containers 1-4 are situated horizontally in relation to each other (see also fig. 3) and are separated by substantially vertical plates (not shown). In such an embodiment, the plates are perforated in order to allow the organic waste material to pass from one container to the other. The perforation is preferably provided at the top of the plates in the housing. Alternatively, when the process containers are situated in one housing, the process containers are situated vertically in relation to each other (not shown) and are separated by substantially horizontal plates (not shown). In such an embodiment, the plates are perforated in order to allow the organic waste material to pass from one container to the other. The perforation is preferably provided at corners or along outer borders of the plates. The four process steps are preferably dimensioned to allow for a process time of each of the four process steps of just 10 minutes. For storage of the coagulant, the negatively charged solid material and the flocculation agent, the plant is further provided with supply containers 5-8 (see fig. 1). A supply container 5 for storage of the coagulant is preferably made either of metal such as steel, of plastic such as polyester resin or of a ceramic such as porcelain. The coagulant solution 5 need not be stirred. The addition of coagulant is controlled proportional to the inlet flow of the organic waste material to the plant. The size of the tank is preferably dimensioned to allow for a mixing time of just 10 minutes. The supply container 6 for storage of negatively charged solid material is preferably made of metal such as steel, of plastic such as polyester resin or of a ceramic such as porcelain. The container is equipped with a stirrer 10 (not shown) to avoid the negatively charged solid material to precipitate or separate into layers. Tap water or water from the process may preferably be added. Further, the supply containers 7 and 8 for storage of the flocculating agent is preferably also equipped with a stirrer (not shown) to avoid separation.

15 After the organic waste material has been treated in the processing steps prior to separation, the at least partly diluted aqueous phase and the at least partly enriched phase being formed are transferred to a number of sieving members, which separates the thus treated organic waste material. The number of sieving members are preferably situated in a container 9 (see fig. 1), where a metal net such as a stainless steel net is mounted

20 above the bottom of the container. As previously mentioned, other solutions of sieving members are applicable. A filter cloth may preferably be laid on the net. Underneath the net, vacuum can be established.

Preferably, a pumping sump 10 functions as a distributing means to allow re-circulation of 25 the at least partly purified first aqueous phase to the upper surface of the at least partly enriched solid phase associated above the sieving member in the container 9, further on to the supply containers or to further treatment. The at least partly enriched solid phase is deposited in a deposition container 11. Situated subsequent to the pumping sump 10, a pump 12 transfers the at least partly purified aqueous phase to a first collection container 30 13. The pump 12 re-circulates the at least partly purified aqueous phase from the pumping sump 10 to the surface of the at least partly enriched solid phase associated with the number of sieving members in the container 9, and the pump 12 also pumps at least partly purified aqueous phase to the supply containers 6-8.

35 In an additional step (see also fig. 4), the at least partly purified first aqueous phase is transferred to a container 14 having means for either microfiltration (MF), ultrafiltration (UF), nano-filtration (NF), reverse osmosis (RO), electrodialysis, electrodeionization, pervaporation, membrane extraction, membrane distillation, membrane stripping, membrane aeration or other processes such as irradiation. The container 16 may also contain an at least divalent positively charged resin. The resin is preferably contained in a conical container, in which 50% of the volume is filled with as example aluminium-charged ion exchange resin. Preferably, there is a valve (not shown) at the bottom of the container 14. Above the ion exchange resin in the container 14, the container 14 is preferably also supplied with a valve (not shown). The aqueous phase in the container can be regulated to exhibit a flow from the bottom of the container 14 and a flow from a level above the resin. The at least partly purified second aqueous phase obtained in this additional step is preferably taken from the bottom of the container 14, and a cation concentrated aqueous phase is withdrawn from a tap preferably at a level above the positively charged resin. The at least partly purified second aqueous phase is transferred to a second collection container 15 or is, if sufficiently purified, removed from the plant.

In a further additional purifying step, the at least partly purified second aqueous phase is transferred to a container 16 preferably containing a negatively charged resin, preferably situated in a conical container. In another embodiment the resins may be allowed to be positive, as long as the ion strength is strong enough to associate the cations of interest. The ion exchanger thus provided herein is constructed as a multicolumn plant with automatic change from one column to another and with automatic regeneration of the resin. In the exchanger, the main part of the rest of the ammonium and the potassium is separated from the aqueous phase. The at least partly purified third aqueous phase obtained in this process is transferred to a third collection container 17.

Fig. 1 furthermore shows dosage pumps 18-21 and a magnetic inductive flow meter 22. The meter transmits signals to regulation equipment (not shown) for the regulation of supply of coagulant, the negatively charged solid material and the flocculation agent, respectively, in process steps 18, 19, 20, 21. Finally, a dosage pump 23 for the introduction of the organic waste material is illustrated.

Fig. 2 illustrates a diagram of a possible first alternative process for carrying out a process according to the invention. A process container 4, preferably with a stirrer as shown, and wherein organic waste material is treated prior to separation is depicted as an alternative embodiment to the four process containers 1-4 shown in fig. 1 The differences between the first alternative process and the process illustrated in fig. 1 are the ones mentioned in the following paragraphs. Accordingly, where the process steps according to the first alternative process of fig. 2 coincides with the process steps of the possible process illustrated in fig. 1, the description related to fig. 1 is incorporated by reference into the description related to fig. 2. Although not shown, the pump 12 may re-circulate the at least partly purified aqueous phase from the pumping sump 10 to the surface of the at least partly enriched solid phase associated with the number of sieving members in the container 9, and although not illustrated as well, the pump 12 may pump at least partly purified aqueous phase to the supply containers 6-8. Thus, although not illustrated, these process steps, which are illustrated in fig. 1, may also be adopted into the first alternative process of fig. 2.

In an additional step, the at least partly purified first aqueous phase is transferred to a container 40 having means for filtration, preferably by means of polymerised fly ash. In the process of filtration, the fly ash forms a permeable, incompressible "cake". Whatever fine solids were originally suspended in the liquid are entrained in the cake as it is built up. The porous nature of the cake prevents such solids from agglomerating and forming an impervious layer on the filter. Various types of filter materials are known other than fly ash, including diatomaceous earth, plastic-coated diatomaceous earth, diatomaceous silica, bentonites, carbon, asbestos, cellulose, pumice, pumicite, obsidian, pitchstone, volcanic ash, volcanic glass, attapulgite clay, wood pulp, kieselguhr, or calcium hypochlorite.

After filtration, the liquid phase is pumped to the container 16 by means of a suitable pump 41. In a further additional purifying step, the at least partly purified second aqueous phase is transferred to a container 16 preferably containing a negatively charged resin, preferably situated in a conical container. In another embodiment, the resins may be allowed to be positive, as long as the ion strength is strong enough to associate the cations of interest. The ion exchanger thus provided herein is constructed as a multicolumn plant with automatic change from one column to another and with automatic regeneration of the resin. In the exchanger, the main part of the rest of the ammonium and the potassium is separated from the aqueous phase.

Fig. 3 illustrates a diagram of a possible second alternative process for carrying out a process according to the invention. A process container 4, preferably with a stirrer as shown, and wherein organic waste material is treated prior to separation is depicted as an alternative embodiment to the four process containers 1-4 shown in fig. 1 The differences between the first alternative process and the process illustrated in fig. 1 are the ones mentioned in the following paragraphs. Accordingly, where the process steps according to the first alternative process of fig. 1 coincides with the process steps of the possible process illustrated in fig. 1, the description related to fig. 1 is incorporated by reference to the description related to fig. 3.

Although not shown, the pump 12 may re-circulate the at least partly purified aqueous phase from the pumping sump 10 to the surface of the at least partly enriched solid phase associated with the number of sieving members in the container 9, and although not illustrated as well, the pump 12 may pump at least partly purified aqueous phase to the supply containers 6-8. Thus, although not illustrated, these process steps, which are illustrated in fig. 1, may also be adopted into the second alternative process of fig. 4.

In an initial step after the at least partly purified aqueous phase is transferred to a container 42. The container 42 is having means for a first filtration, in the embodiment shown a sand filter. Other filters than sand filters may be employed for entraining more coarse particles. After having passed the sand filter the still at least partly purified aqueous phase is transferred to an additional step by means of a pump suitable for pumping the aqueous phase in the present state.

In an additional step the at least partly purified first aqueous phase is transferred to container 43. The container 43 are having means for further filtration, in the embodiment shown a nano-filtration filter or a reverse osmosis filter, also known as hyper-filtration, or perhaps even a combination of both filtration processes.

Reverse osmosis uses a membrane that is semi-permeable, allowing the fluid that is being purified to pass through it, while rejecting the contaminants that remain. Reverse osmosis is capable of rejecting bacteria, salts, sugars, proteins, particles, dyes, and other constituents that have a molecular weight of greater than 150-250 daltons. The separation of ions with reverse osmosis is aided by charged particles. This means that dissolved ions that carry a charge, such as salts, are more likely to be rejected by the membrane than those that are not charged, such as organics. The larger the charge and the larger the particle, the more likely it will be rejected. A percentage of the aqueous phase may not pass through the membrane, but may flow across the membrane surface, thereby cleaning it and carrying the inorganic and organic solids to an outlet.

Nano-filtration is a form of filtration that uses membranes to preferentially separate different fluids or ions. Nano-filtration is not as fine a filtration process as reverse osmosis, but it also does not require the same energy to perform the separation. Nano-filtration also uses a membrane that is partially permeable to perform the separation, but the membrane's pores are typically much larger than the membrane pores that are used in reverse osmosis. Nano-filtration is capable of concentrating sugars, divalent salts, bacteria, proteins, particles, dyes, and other constituents that have a molecular weight greater than 1000 daltons. Nano-filtration, like reverse osmosis, is normally affected by the charge of the particles being rejected. Thus, particles with larger charges are more likely to be rejected than others. Other sub-filtration means than nano-filtration means in the container 43 comprises the utilisation of ultra-filtration, micro-filtration, selective filtration or particle filtration.

Preferably, there is a valve (not shown) at the bottom of the filter container 43. The container 43 is preferably also supplied with a valve (not shown). The aqueous phase in the container can be regulated to exhibit a flow from the bottom of the container 43.This is a concentrated phase containing nitrogen and potassium. Alternatively or additionally, the purified aqueous phase obtained in this additional step may be taken from the top part of the container 43, and the aqueous phase is withdrawn and re-circulated to the supply containers 6-8 for assisting continued treatment according to the preceding process steps. From the side of the container 43 the purified aqueous phase is taken away as ready for discharge or other utilisation as purified aqueous phase.

Turning to the separation process of organic waste material, fig. 4 illustrates the separation of organic waste material and further how the at least partly purified first aqueous phase is re-circulated. After the processing steps in the process containers 1-4 (see fig. 1) or the one container 4 (see fig. 2 and fig. 3), the organic waste material is transferred to a container 9, to the surface 9a of an at least partly enriched solid phase that is accumulated in a layer 9b associated to the one or more sieving members 9c. The at least partly purified first aqueous phase obtained after the separation is transferred to the pumping sump 10 (see also fig. 1, 2 and 3) by means of a pump 24 (not shown in fig. 1). When the aqueous phase has traversed the at least partly enriched solid phase 9b and has traversed the one or more sieving members 9c, which in this situation is a metal filter with a cloth, it is in some circumstances re-circulated by means of the pump 12 (see also fig. 1) through a pipe 25 to the top surface 9a of the at least partly enriched solid phase.

The separate process containers 1-4 or the one container 4 are most preferably located in one housing, preferably within a rectangular housing as illustrated in fig. 5. In one presently preferred embodiment, in which the separate process containers are located in one housing, the process containers are arranged horizontally starting with the at least one separate first process container 1 at a first end to the left, then the at least one separate second process container 2 in the middle, and finally the at least one separate third process container 3 at a second end to the right. The process containers 3 and 4 in fig. 1 is combined in the one and same process container 3 in fig. 5. In a more preferred embodiment, the horizontally arranged separate containers are separated by plates 26 and 27 as shown, and where each of the plates 26,27 preferably are provided with at least one opening 28 and 29. In a still more preferred embodiment, the openings 28,29 are situated at the top of the plates 26,27 as shown and is of substantially rectangular shape. When required, a second separation process step 14 (see also fig. 1) is provided, as illustrated in fig. 6. The at least partly purified first aqueous phase is transferred through at least one pipe 30 leading from the process step 13 (see fig. 1) to a top 31 of a container containing at the bottom one or more at least divalent positively charged resins 32. The at least partly purified first aqueous phase associates with the one or more at least partly divalent positively charged resins 32, and at least part of the cations of the at least partly purified first aqueous phase is repelled. The at least partly purified second aqueous phase obtained in the purification of the second separation process step 14 is let out through a pipe 33 at the bottom of the container and the concentrated aqueous phase containing cations is let out through a pipe 34 at a level above the resins. The pipe 33 leads back to the pumping sump 10 (see fig. 1) and the pipe 34 leads to the process step 15 (see fig. 1).

Starting up the plant before running the plant with organic waste material: At first, the supply container for coagulant is filled with coagulant solution, whereas the supply container for negatively charged solid material is supplied with water from the pumping sump and negatively charged solid material is introduced while stirring.

The supply containers for the flocculating agent are additionally supplied with water from the pumping sump, and the flocculating agent is likewise added while stirring. The one or more sieving members are then provided with a filter cloth. Adjustment of the pump for introducing coagulant to the treatment is performed. Adjustment is likewise performed of the pump for adding negatively charged solid material and the pumps for adding flocculation agents.

Running the plant with organic waste material after having started up the plant:

Organic waste material is pumped to the plant, optionally added water. The at least partly enriched solid material is then build up on the one or more sieving members. To allow the aqueous phase to traverse to one or more filters vacuum is established underneath the one or more sieving members. If appropriate, re-circulation is initiated and thus is adjusted to correspond to the amount of the at least partly purified first aqueous phase that traverses the sieving members and the inlet of organic waste material to the plant. The at least partly purified first aqueous phase is optionally let from the first collecting container to the at least divalent positively charged resins. Concentrated water from above the resin is returned to the pumping sump. The at least partly purified second aqueous phase is transferred to a second collection container. Optionally, the at least partly purified second aqueous phase from the second collecting container is transferred to at divalent negatively charged resins, and-the at least partly purified third aqueous phase from the divalent negatively charged resins is transferred to a third collecting container. EXAMPLES OF ANALYSIS RESULTS

An organic waste material was treated according to the present invention. In the present experiment manure was selected and treated.

Raw manure containing ammonia, phosphor and potassium was used in the present experiment performed in the laboratory. The pH of the manure was adjusted to around 5,5 prior to processing, so as to let a major part of the ammonia be in the form of ammonium. The whole content of nitrogen, phosphor and potassium, both in organic and inorganic form, was measured for 5 samples with the following mean result:

Nitrogen: 4300 mg/l Phosphor: 530 mg/l Potassium: 2500 mg/I

After pH adjustment, 800 ml of the raw manure was transferred to a cylindrical porcelain funnel having a flat bottom, and a filter paper with a medium mask size was associated to the bottom. The filter had a diameter of 200 mm. Vacuum at 0,8 bar was created under the funnel by a water jet pump. While preparing the funnel, a coagulant, a negatively charged solid material and a flocculating agent were added to the raw manure in 1000ml beakers. Iron (III) sulphate was chosen as coagulant, bentonite was chosen as negatively solid material and a high molecular cationic polymer was chosen as the flocculating agent. The ingredients were stirred. Phosphor was precipitated reacting with iron (III) sulphate, which furthermore initiated flocculation, ammonia and potassium were associated to the bentonite and the negatively charged solid material present in the manure, and the high molecular cationic polymer made the solid phase of the manure flocculate.

After the mixture had reacted for 3-4 min., the mixture was transferred to the funnel. The obtained at least partly purified first aqueous phase was collected in a conical flask for later processing and for analysis. After the first purification step, the whole content of nitrogen, phosphor and potassium was measured for 5 samples with the following mean result:

Nitrogen: 970 mg/l Phosphor: 0 mg/l Potassium: 1000 mg/l

After separation of the aqueous phase and the solid phase, the at least partly purified first aqueous phase was immediately transferred to a second purification step comprising positively charged resins. The basic of the resins was made of plastic impregnated with 20% aluminium chloride solution. The resins were filled in a glass column, and the first purified aqueous phase traversed the resins after 5 min. to obtain a second purified aqueous phase, which was collected for further treatment and analysis. A cation concentrated aqueous phase was regularly discarded from the top of the resins.

After the second purification, the whole content of nitrogen, phosphor and potassium was measured for 5 samples with the following mean result:

Nitrogen: 220 mg/l Phosphor: 0 mg/l Potassium: 0 mg/l

The at least partly purified second aqueous phase was immediately transferred to a third purification step comprising negatively charged resins. The basic of the resins was made of plastic impregnated with 10% sodium chloride solution. The resins were filled in a glass column, and the second purified aqueous phase traversed the resins after 5 min. to obtain a third purified aqueous phase, which was collected for further treatment and analysis.

After the third purification, the whole content of nitrogen, phosphor and potassium was measured for 5 samples with the following mean result:

Nitrogen: 0.56 mg/l Phosphor: 0 mg/l Potassium: 0 mg/l

Claims

1. A method of treatment of an organic waste material containing an aqueous phase and a solid phase, the method comprising the following steps

(a) processing the organic waste material by

2. A method according to claim 1, wherein the at least partly purified first aqueous phase is transferred to one or more reverse osmosis unit(s) separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the reverse osmosis unit(s), so that the at least partly purified first aqueous phase traversing the reverse osmosis unit(s) is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

3. A method according to claim 1, wherein the at least partly purified first aqueous phase is transferred to one or more nano-filtration unit(s) separating the at least partly purified first aqueous phase, thereby at least partly preventing the cations to traverse the nano- filtration unit(s), so that the at least partly purified first aqueous phase traversing the nano-filtration unit(s) is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

4. A method according to claim 1, wherein the at least partly purified first aqueous phase is transferred to one or more positively charged resins containing at least divalent positively charged ions, the one or more positively charged resins repelling the cations, thereby at least partly preventing the cations to traverse the one or more positively charged resins, so that the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

5. A method according to any of claims 2-4, wherein the at least partly purified second aqueous phase contains at the most 5% wt. of the nitrogen, at the most 5% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

6. A method according to claim 4, wherein the one or more positively charged resins contain at least trivalent positively charged ions.

7. A method according to claim 6, wherein the at least trivalent positively charged ion is selected from the group consisting of aluminium and salts thereof.

8. A method according to any of claims 2-7, wherein the at least partly purified second aqueous phase is transferred to one or more negatively charged resins containing anions, the one or more negatively charged resins adsorbing the cations, thereby at least partly preventing the cations to traverse the one or more negatively charged resins, so that the at least partly purified second aqueous phase traversing the one or more negatively charged resins is further purified, obtaining an at least partly purified third aqueous phase containing at the most 1% wt. of the nitrogen, at the most 1% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

9. A method according to any of claims 1-8, wherein the pH value prior to treatment of the organic waste material is decreased to at least to 6.5.

10. A method according to any of claims 1-9, wherein the organic waste material is selected from the group consisting of manure, wastewater, industrial water, institutional water, water from households, water from fishing industries, water from manufacturing

5 industries and water from processing industries.

11. A method according to any of claims 1-10, wherein the cations of the organic waste material is selected from the group consisting of ions of nitrogen, potassium, cadmium, copper, zinc, and toxicological injurious compounds, and any combination and derivatives

10 thereof.

12. A method according to any of claims 1-11, wherein the negatively charged solid material is a negatively charged organic material.

15 13. A method according to claim 12, wherein the negatively charged solid material is added to the organic waste material.

14. A method according to claim 12, wherein the negatively charged organic material is contained in the organic waste material.

20

15. A method according to any of claims 1-11 wherein the negatively charged solid material is a mineral, such as an aluminosilicate mineral.

16. A method of treatment of an organic waste material containing an aqueous phase and 25 a solid phase, the method comprising the following steps

(a) processing the organic waste material by

subjecting the organic waste material to at least one coagulant, thereby precipitating at 30 least 90% wt. of the phosphor ions and initiating flocculation of the solid phase and thus excluding at least part of the anions from the aqueous phase,

allowing at least part of the cations of the organic waste material to associate to negatively charged solid materiel, thereby excluding at least part of the cations from the aqueous 35 phase, and

introducing at least one flocculating agent, thereby obtaining an at least partly diluted aqueous phase and an at least partly enriched solid phase; (b) separating the at least partly enriched solid phase obtained in step (a) from the at least partly diluted aqueous phase using a number of sieving members accumulating the at least partly enriched solid phase at the upper surface of the number of sieving members, thus in a controlled manner

5 allowing the at least partly diluted aqueous phase to traverse both the at least partly enriched solid phase and the number of sieving members, thereby letting at least part of the cations associate to negatively charged solid materiel, thereby

10 obtaining an at least partly purified first aqueous phase containing at the most 30% wt. of the nitrogen, at the most 40% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material; and

(c) transferring the at least partly purified first aqueous phase obtained in step (b) to one 15 or more reverse osmosis unit(s) separating the at least partly purified first aqueous phase, thereby at least partly

preventing the cations to traverse the reverse osmosis unit(s), so that the at least partly purified first aqueous phase traversing the reverse osmosis unit(s) is further purified,

20 obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material, or transferring the at least partly purified first aqueous phase obtained in step (b) to one or more sub-filtration unit(s), preferably

25 nano-filtration unit(s), separating the at least partly purified first aqueous phase, thereby

at least partly preventing the cations to traverse the sub-filtration unit(s), so that the at least partly purified first aqueous phase traversing the sub-filtration unit(s) is further purified, obtaining an at least partly purified second aqueous phase containing at the most 30 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

17. A method according to claim 16, wherein the at least partly purified second aqueous phase obtained in step (c) contains at the most 5% wt. of the nitrogen, at the most 5%

35 wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

18. A method according to any of claims 16-17, wherein the at least partly purified second aqueous phase is transferred to one or more negatively charged resins containing anions, the one or more negatively charged resins adsorbing the cations, thereby at least partly preventing the cations to traverse the one or more negatively charged resins, so that the at least partly purified second aqueous phase traversing the one or more negatively charged resins is further purified, obtaining an at least partly purified third aqueous phase 5 containing at the most 1% wt. of the nitrogen, at the most 1% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

19. A method according to claim 16-18, wherein the pH value prior to treatment of the organic waste material is decreased to at least to 6.5.

10

20. A method according to any of claims 16-19, wherein the organic waste material is selected from the group consisting of manure, waste water, industrial water, institutional water, water from households, water from fishing industries, water from manufacturing industries and water from processing industries.

15

21. A method according to any of claims 16-20, wherein the cations of the organic waste material is selected from the group consisting of ions of nitrogen, potassium, cadmium, copper, zinc, and toxicological injurious compounds, and any combination and derivatives thereof.

20

22. A method according to any of claims 16-21, wherein the negatively charged solid material is a negatively charged organic material.

23. A method according to claim 22, wherein the negatively charged solid material is 25 added to the organic waste material.

24. A method according to claim 22, wherein the negatively charged organic material is contained in the organic waste material.

30 25. A method according to any of claims 16-24, wherein the negatively charged solid material is a mineral, such as an aluminosilicate mineral.

26. A method of treatment of an organic waste material containing an aqueous phase and a solid phase, the method comprising subjecting an at least partly purified first aqueous 35 phase of organic waste material to one or more positively charged resins containing at least divalent positively charged ions, the one or more positively charged resins repelling the cations, thereby at least partly preventing the cations to traverse the one or more positively charged resins, so that the at least partly purified first aqueous phase traversing the one or more positively charged resins is further purified, obtaining an at least partly purified second aqueous phase containing at the most 10% wt. of the nitrogen, at the most 10% wt. of the potassium and at the most 1% wt. of the phosphor present in the organic waste material.

5 27. A method according to claim 26, wherein the one or more positively charged resins contain at least trivalent positively charged ions.

28. A method according to claim 27, wherein the at least trivalent positively charged ion is selected from the group consisting of aluminium and salts thereof.

10

29. A plant for treatment of an organic waste material containing an aqueous phase and a solid phase, the plant comprising means for introducing the organic waste material to at least one process container, and said plant furthermore comprising

15 supply means for dosage of supply media to the at least one process container including supply means for dosage of at least one coagulant from a number of coagulant supply containers,

supply means for dosage of negatively charged solid materiel from a number of supply 20 containers containing negatively charged solid material and

supply means for dosage of at least one flocculating agent from a number of flocculating agent supply containers, and said plant furthermore comprising

25 a number of sieving members situated after the at least one process container, the number of sieving members separating an at least partly enriched solid phase from an at least partly diluted aqueous phase, and accumulating the at least partly enriched solid phase at the upper face of the number of sieving members, and said plant furthermore comprising

30 means for distributing an at least partly purified first aqueous phase after traversing the number of sieving members to a first collection container and means for distributing the at least partly enriched solid phase to a deposition container,

35 30. A plant according to claim 29, further comprising means for distributing the at least partly purified first aqueous phase to one or more positively charged resins containing at least divalent positively charged ions, the plant further comprising a second collection container for collecting an at least partly purified second aqueous phase traversing the one or more positively charged resins.

31. A plant according to claim 29, further comprising means for distributing the at least partly purified second aqueous phase to one or more nano-filtration unit(s).

5 32. A plant according to claim 29, further comprising means for distributing the at least partly purified second aqueous phase to one or more reverse osmosis unit(s).

33. A plant according to any of claims 29-32, further comprising means for re-circulating the collected at least partly purified first aqueous phase to the upper surface of the sieving

10 member.

34. A plant according to any of claims 29-33, further comprising means for re-circulating the collected at least partly purified second aqueous phase to the upper surface of the sieving member.

15

35. A plant according to any of claims 29-34, further comprising means for re-circulating the collected at least partly purified third aqueous phase to the upper surface of the sieving member.

20 36. A plant according to any of claims 33-35, wherein the means for re-circulating the collected at least partly purified aqueous phase is capable of distributing the collected at least partly purified aqueous phase to the upper surface of the at least partly enriched solid phase accumulated at the upper surface of the sieving member.

25 37. A plant according to any of claims 29-36, wherein the supply means comprise a dosage pump being situated between the supply container containing the supply media and the process container for the organic waste material.

38. A plant according to claim 37, wherein the supply media in the supply container is 30 mixed with liquid prior to dosing.

39. A plant according to claim 38, wherein the liquid is collected from re-circulation of treated organic waste material.

35 40. A plant according to claim 39, wherein the organic waste material is from at least partly purified first, second or third aqueous phase or any combination thereof.

41. A plant according to any of claims 29-40, wherein the one or more coagulant supply containers are connected to at least one separate first process container, the one or more supply containers containing negatively charged solid material are connected to at least one separate second process container and the one or more flocculating agents supply containers are connected to at least one separate third process container.

5 42. A plant according to claim 41, wherein the at least one process containers are arranged starting with the at least one separate first process container, then the at least one separate second process container and finally the at least one separate third process container.

10 43. A plant according to claim 42, wherein the separate process containers are located in one housing, preferably within a rectangular housing.

44. A plant according to claim 43, wherein the separate process containers being located in one housing are arranged vertically starting with the at least one separate first process

15 container at the top, then the at least one separate second process container at the middle and finally the at least one separate third process container at the bottom.

45. A plant according to claim 44, wherein the vertically arranged separate containers are separated by plates, and wherein the plates preferably are provided with at least one

20 opening, more preferred being provided with openings in diagonally opposite corners of plates of a substantially rectangular shape, and where the organic waste material preferably is intended for being passed through the holes of the plates by means of gravity.

25 46. A plant according to claim 45, wherein the separate process containers being located in one housing are arranged horizontally starting with the at least one separate first process container at one side, then the at least one separate second process container at the middle and finally the at least one separate third process container at other side.

30 47. A plant according to claim 46, wherein the horizontally arranged separate containers are separated by plates, and wherein the plates preferably are provided with at least one opening, more preferred being provided with openings at the top of the housing of a substantially rectangular shape, and where the organic waste material preferably is intended for being passed through the holes of the plates by means of gravity.

35

48. A plant according to any of claims 29-47, wherein the at least a number of the sieving members, preferably all the sieving members, are filters.

49. A plant according to claim 48, wherein filtering cloths are associated with the filters constituting the sieving members.

50. A plant according to any of claims 30-49, wherein the one or more positively charged resins comprise pellets impregnated with ions of aluminium.

51. The method according to any of claims 1-28, wherein the coagulant is a polymer.

52. The method according to any of claims 1-28, wherein the coagulant is Fe (III).