HK1110366B

HK1110366B - Wastewater treatment

Info

Publication number: HK1110366B
Application number: HK08100961.7A
Authority: HK
Inventors: 安德鲁．W．戈登
Original assignee: 水质标准股份有限公司
Priority date: 2004-04-23
Filing date: 2005-04-25
Publication date: 2013-03-15

Description

Treatment of waste water

Cross Reference to Related Applications

This application claims priority to U.S. provisional patent application 60/564,921 filed on 8/23/2004.

Technical Field

The present invention relates to an apparatus, system and method for treating wastewater.

Background

Residential, commercial, agricultural, and industrial water use produces large amounts of untreated wastewater that can cause health hazards and environmental problems. Therefore, most cities use wastewater treatment facilities downstream of their sewage collection systems to treat raw wastewater into a less harmful form.

The wastewater entering the treatment facility (influent) is a mixture of approximately 99% water and 1% large objects, solids, dissolved solids, oils, waxes, and organics. The latter can be separated from the former by using a series of processing steps, which are commonly referred to as pre-processing, primary processing, secondary processing, and advanced processing. Pretreatment and primary treatment remove solids. Secondary treatment uses microorganisms to remove dissolved organic matter. Advanced (tertiary) treatments scavenge nutrients such as nitrogen and phosphorus. Other treatments include disinfection, filtration and reverse osmosis.

The end products of conventional wastewater treatment systems are treated wastewater and sludge. The treated wastewater is typically discharged into a body of water (e.g., a stream, river, or ocean) near a wastewater treatment plant. The sludge is usually dumped to specific areas outside the plant area and is sometimes treated for use as fertilizer.

The production and disposal of these end products, as well as the routine operation of wastewater treatment plants, may be undesirable. For example, the treated wastewater is continuously discharged into nearby bodies of water and may be harmful to the environment. In addition, the resulting sludge can generate strong odors that render areas near the wastewater treatment plant unsuitable for perching or dwelling.

Disclosure of Invention

The present invention relates to an apparatus, system and method for treating wastewater. In these systems and methods, at least a portion of the wastewater treatment is conducted offshore at the shore. For example, sewage from a municipal sewage system is first subjected to primary treatment on land. The wastewater after such treatment may be transported (e.g., by piping) to facilities located on the shore (e.g., a vessel fixed in a body of water) for one or more of secondary treatment, disinfection, and advanced treatment. The resulting treated wastewater may be discharged offshore or returned to land for further treatment or utilization. The resulting sludge may be returned to land for stacking or further processing. The sludge may also be further processed (e.g., decomposed and dewatered) on the processing vessel before being returned to land.

Because the apparatus, system, and method of the present invention can be implemented offshore, the disadvantages associated with conventional onshore wastewater treatment operations can be avoided. For example, because the discharged treated wastewater can be evacuated offshore, particularly the treated wastewater is first mixed with water of the surrounding environment and then discharged, the impact of the discharge of the treated wastewater on the local environment is mitigated. In addition, the ship-based treatment system can increase the treatment efficiency by increasing the hydraulic retention time through the swaying of the ship in the water body. Importantly, the use of such an offshore wastewater treatment system reduces the amount of land-based use required to treat the wastewater, eliminating hazards to the area, such as foul odors. The offshore system of the invention can extend service life by upgrading modules that are difficult to implement in existing land based facilities. Furthermore, the mobility of certain ship-based systems makes them applicable in emergency and military applications.

Accordingly, the invention features an offshore wastewater treatment vessel (or other offshore facility) that includes a wastewater treatment system capable of treating at least 2,000 million liters of wastewater per day; a wastewater inlet in fluid communication with the wastewater treatment system; and a water outlet for removing treated wastewater from the vessel. The wastewater treatment system may include a primary treatment system for reducing the content of suspended solids or grease in the wastewater; a secondary treatment system comprising bacteria capable of reducing the amount of organic matter contained in the wastewater; a sterilization treatment system including a means for killing microorganisms; a nutrient removal system including a device for removing nutrients including nitrogen and phosphorus from wastewater. The wastewater treatment system may include a sludge treatment system including, for example, a means for removing water from sludge, a bacteria-mediated means for decomposing organic matter, and/or a disinfection system including a means for killing microorganisms.

The offshore wastewater treatment vessel may also include other components such as power generation equipment, a propulsion system for moving the treatment vessel, and/or a chamber for mixing treated wastewater or sludge with water in the body of water surrounding the treatment vessel.

Another aspect of the invention features a wastewater treatment facility located in a body of water remote from an onshore wastewater collection system. The wastewater treatment apparatus includes: (a) a wastewater treatment assembly capable of treating at least 20,000 million liters of wastewater per day; (b) means (e.g., piping or shuttle vessels) for transferring wastewater from an onshore wastewater collection system to a wastewater treatment facility; (c) means for removing treated wastewater from the wastewater treatment system (e.g., a water outlet, a pipe, or a shuttle vessel in fluid communication with a body of water); and (d) means (e.g., piping or a shuttle vessel) for removing sludge from the wastewater treatment system. The wastewater treatment facility of the present invention may also include at least two separate wastewater treatment modules that differ in the manner in which the wastewater is treated. The two separate wastewater treatment modules may be separated by a body of water (e.g., two or more vessels floating on the body of water and connected so that wastewater can flow from at least one vessel to at least one other vessel).

In another aspect, the invention features a method of treating wastewater including the steps of: transporting wastewater from a location on land to a wastewater treatment facility located in a body of offshore water, and then passing the wastewater through: a primary treatment system to reduce the content of suspended solids or grease in the wastewater; a secondary treatment system comprising bacteria capable of decomposing organic matter contained in the wastewater; a sterilization treatment system including means to kill microorganisms; and/or a nutrient removal system comprising means to remove nutrients including nitrogen and phosphorous in the wastewater. The resulting treated wastewater and sludge may be transferred from the wastewater treatment facility to a location onshore or discharged into a body of water. In the latter case, the final product is diluted prior to discharge to reduce environmental impact.

Unless defined otherwise, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the specific embodiments discussed below are illustrative only and not limiting to the invention.

Drawings

FIG. 1 is a side view of a water treatment system of the present invention;

FIG. 2 is a side view of the water treatment system of the present invention;

FIG. 3 is a perspective view of the water treatment system of the present invention;

FIG. 4A is a side view of the offshore wastewater treatment vessel of the present invention;

figure 4B is a side view of another offshore wastewater treatment vessel of the present invention.

Detailed Description

The present invention provides an offshore apparatus, system and method for treating wastewater. Briefly, the system and method of the present invention comprises or uses an offshore wastewater treatment facility, means for transferring wastewater from a location on land to the offshore wastewater treatment facility, means for transferring wastewater for treatment from the offshore wastewater treatment facility; and means for transferring sludge from said offshore wastewater treatment facility.

The present invention comprises an offshore wastewater treatment facility for treating wastewater from land. The wastewater delivered to the offshore wastewater treatment facility from land may come from many sources, including domestic, industrial, governmental, or agricultural sources. The offshore wastewater treatment facility of the present invention is capable of treating wastewater from any of these sources and may be designed or modified to treat a particular type of wastewater.

In the embodiment shown in fig. 1-4, the offshore wastewater treatment facility shown is a vessel 10, including wastewater treatment assemblies 20a, 20b, 20c, and 20d mounted at least partially within the hull (hull)11 of the vessel 10. In fig. 1 and 2, the wastewater from the onshore wastewater collection system 60 is first delivered to an onshore wastewater pretreatment module 200 for treatment. The resulting treated wastewater is then transported to the vessel 10 via conduit 120. The wastewater is then directed to wastewater treatment assemblies 20a, 20b, 20c, and 20d on board the vessel 10 for further treatment. In the embodiment shown in fig. 1-3, the final product of the wastewater treatment process is sludge 275 and treated wastewater. These end products may be returned to land for additional treatment or disposal or discharged into the body of water 30 surrounding the vessel 10. Referring to fig. 1, the treated wastewater is discharged into a body of water 30, and a tug barge 70 is used to carry the sludge 275 back to the surface. In the embodiment shown in fig. 2 and 3, both the sludge 275 and the treated wastewater are brought back to the surface 130.

The offshore wastewater treatment facility of the invention can be any facility that (a) can be located at the surface of a body of water and (b) can carry at least one wastewater treatment assembly. Many of these types of equipment are known in the art, for example, vessels such as a carrier (as shown in fig. 1-4), barges (barges), a series of interconnected carriers and/or barges, or a floating platform secured to the bottom of a body of water. These vessels may be self-propelled, non-self-propelled, manned or unmanned. In general, the water treatment systems of the present invention may be configured to treat more than 300 million (e.g., greater than 250, 200, 500, 1000, 1500, 2000, 2500, 5000, 1, 2, 3, 4, 5, or 6 or more) liters of wastewater per day.

In one embodiment, the offshore wastewater treatment plant is a mono-or bi-hull vessel, e.g., having a tonnage (abbreviated as dwt) of between 10,000 and 500,000, such as 30,000 and 50,000; 65,000 and 80,000; 120,000; or 250,000 and 300,000. The optimum tonnage capacity depends on the particular design of the given system (e.g., the amount of wastewater treated per cycle), but should be sufficient to maintain the minimum draft (draft) required to keep the vessel afloat, and/or match the expected vessel treatment capacity. The offshore wastewater treatment vessel of the invention may also include features such as those described in U.S. provisional patent application 60/564,921, such as one or more noise and/or vibration reduction devices, a water storage tank (in this case, for storing treated wastewater prior to discharge from the treatment vessel), a power source for powering one or more functions of the vessel, propulsion devices for moving the vessel in a body of water, and/or a control system for controlling the operation of various systems onboard the vessel (e.g., a wastewater intake system, a treated wastewater discharge system, a treated wastewater transfer system, and a power source).

As shown in fig. 1-4, at least a portion of one or more wastewater treatment assemblies may be mounted on a main deck of an offshore wastewater treatment facility. For example, one or more wastewater treatment modules may be partitioned within the vessel and interfaced with each other and connected to the main deck. Additionally, at least a portion of the one or more wastewater treatment components are mounted below a main deck of the offshore wastewater treatment facility. One or more wastewater treatment components may also be installed both above and below the main deck of the offshore wastewater treatment facility.

The offshore wastewater treatment facility may further comprise at least one (e.g., 1, 2, 3, 4, 5, 10, or more) wastewater inlet and at least one (e.g., 1, 2, 3, 4, 5, 10, or more) treated wastewater discharge or vibratory multi-port diffuser structure through which treated wastewater is discharged from the offshore wastewater treatment facility.

The offshore wastewater treatment plant may comprise at least one wastewater treatment assemblySuch as wastewater treatment modules 20a, 20b, 20c and 20d shown in fig. 1-3. Wastewater treatment components suitable for use in the present invention may be any component capable of performing at least one step in a wastewater treatment protocol, for example, removing one or more non-aqueous materials such as solids, grease, wax, organics, and dissolved solids from wastewater. Components for land-based wastewater treatment are well known in the art, see, for example, Syed r. qasmim, ed. published 1998 by CRC Press corporation "wastewater treatment plant: planning, designing and operating second edition (A)Wastewater Treatment Plants：Planning，Design，and Operation， Second EditionSyed r.qasim, ed., CRC Press, 1998); and design of municipal wastewater treatment plant (Ashe engineering practice Manual and report), 4 th edition (1998) ((R))Design of Municipal Wastewater Treatment Plants(AsceManual and Reports on Engineering Practice)，4^thedition, American society of Civil Engineers, 1998). These components can be used in the ship-based system and method of the present invention with little or no modification.

In some embodiments of the invention, the various components that make up the overall wastewater treatment system are all housed in one or more vessels. However, it is often the case that some of the components that make up the overall wastewater treatment system are located on one or more offshore wastewater treatment facilities, while other components are located in one or more ground-based facilities. For example, in the embodiment shown in fig. 1-3, the pre-processing assembly 200 is located on the surface 130.

Wastewater treatment components that may be included in the present invention are: a pre-treatment component, a primary treatment component, a secondary treatment component, a final treatment component, an advanced treatment component, and a reverse osmosis treatment component. In a typical configuration, the wastewater is treated sequentially in the order listed above.

In one embodiment of the invention, the wastewater treatment steps performed on the body of water are all performed in a single offshore facility having all of the wastewater treatment components required to complete the steps. In other embodiments, the wastewater treatment step performed on the body of water is performed in at least two offshore installations, each having at least one different wastewater treatment component. For example, a first vessel may include components that perform primary and secondary processing, and a second vessel may include components that perform final and/or advanced processing. In the latter case, the treated wastewater on the first vessel will be transferred to the second vessel for further treatment.

The pretreatment module of the wastewater treatment system of the present invention may be any device capable of removing large objects or debris such as noodles, debris, large food particles, sand, and grit from wastewater. One example of a system suitable for performing the pretreatment is a set of grates or screens through which the wastewater flows. As the waste water flows through the grate/screen, large objects/debris are filtered out, while the remaining waste water flows through for further treatment. In one preferred configuration, multiple grids or screens are used to filter out objects larger than 5, 4, 3, 2, 1, 0.5, or 0.2 cm. The wastewater treated by the pretreatment component is further subjected to primary treatment.

The primary treatment assembly of the wastewater treatment system may employ any suitable means for removing undissolved solids or liquids from the wastewater. An example of a suitable apparatus is a sedimentation basin system. In such systems, the flowing waste water is introduced into a storage tank for a period of time sufficient for the particles to settle to the bottom and for grease and other materials of lesser density than the waste water to float to the top. Solids are then removed from the bottom of the tank and grease and other floaters are removed from the top. A coagulant may also be used in this process to speed up the precipitation process. Then, the treated wastewater remaining in the tank body is transferred. The waste water after primary treatment can be further treated in a secondary way.

The secondary treatment component of the wastewater treatment system of the present invention may be any device capable of microorganism-mediated removal of organic matter from wastewater. These facilities are provided with bacteria and other microorganisms that metabolize organic matter and with a suitable environment for such processing, e.g., one or more containers with mixers and aerators (e.g., a sequential batch processing reactor available from Aqua-aerobics systems, Inc. of Rockford, Ill.). Methods of adding microorganisms to wastewater include fixed membrane systems, suspended membrane systems, and/or lagoon systems (lagoon systems). One example of a secondary processing component is the AquaMB System, available from Aqua-Aerobic systems, Inc. Such systems include microfiltration units produced by PALL corporation (located in cutland, n.y., usa).

In secondary treatment systems, microorganisms are growing in size and number as a result of absorbing organic and nutrient components in wastewater. After suspending for several hours (e.g., 1.5, 2.0, 2.5, 3.0, 3.5 hours), the microorganisms settle to a sludge. Some of this sludge is removed for disposal or treatment, and some remains in the system as "seed" microorganisms for treatment of other wastewater.

After being treated in the secondary treatment tank, the wastewater is guided to a plurality of different places. In some embodiments of the invention, the secondary treated wastewater is either discharged from the system (e.g., returned to the environment) or is left in the system for other treatment, such as final or advanced treatment.

The final treatment assembly of the wastewater treatment system of the present invention may employ any equipment or reagents suitable for disinfecting wastewater. For example, chlorine or ultraviolet radiation may be used to disinfect the secondary treated wastewater. In the case of chlorine disinfection of water, the final treatment also involves the addition of chlorine-neutralizing chemicals to the treated wastewater, since high levels of chlorine in the treated wastewater can have a negative environmental impact on the body of water to be discharged.

The advanced (tertiary) treatment of the wastewater treatment system may employ any equipment or agent suitable for removing nutrients from the treated wastewater. Advanced treatment involves adding chemicals to the treated wastewater to help precipitate or remove phosphorus or nitrogen. For example, the coagulant may be used to remove phosphorus from the wastewater, and the ammonia may be removed by air scrubbing.

The wastewater treatment system of the present invention may include a filtration module and a reverse osmosis module. For example, the secondary and/or advanced treated wastewater may be treated using one or more filtration steps to filter out undissolved solids and microorganisms. In an exemplary embodiment, the wastewater after at least two stages of treatment is filtered through a filter with a pore size of 10 microns and a filter with a pore size of 0.1 micron in sequence. The waste water treated in this way is suitable for agricultural or industrial use.

In the present invention, the wastewater may be further purified using reverse osmosis to remove dissolved solids. The reverse osmosis system used in the present invention includes a high pressure pump and a reverse osmosis membrane. The high pressure pump used to force the wastewater through the reverse osmosis membrane can be any pump suitable for generating the water pressure required to force the wastewater through the reverse osmosis membrane. The wastewater treated in this way can be made into drinking water.

The wastewater treatment system of the present invention also includes means for transferring wastewater from a location at the surface to an offshore facility having at least one wastewater treatment module. The wastewater to be treated is typically from an onshore wastewater collection system. A wastewater collection system is a system that collects municipal wastewater and sewage. The wastewater collection system includes one or more structures (e.g., buildings) for collecting wastewater and sewage. There are a number of known devices for transferring fluids from a location (e.g., a wastewater collection system) on land to an offshore facility. Any suitable means may be used with the present invention. For example, wastewater may be transported from a location on land to an off-shore facility using a shuttle vessel (e.g., a transport vessel) or barge equipped with one or more storage tanks and equipment to access and remove the wastewater from the storage tanks. For efficiency, the optimal means for transferring fluid from a location 140 on land to the vessel 10 in the body of water is the pipeline 120, as shown in figures 1 to 3. For example, in fig. 1, pipe 120 serves as a conduit through which wastewater is transferred from wastewater collection system 60 and/or with wastewater pretreatment module 200 to a wastewater intake system on board vessel 10. The wastewater influent system is capable of receiving wastewater from a floating, submerged (e.g., seabed) or fixed subsea pipeline.

The first end of the pipeline fixed to the seabed may be placed on the surface of the water. The first end of the pipeline fixed to the seabed communicates with the offshore device of the invention. The second end of the pipeline, which is fixed to the sea bottom, is placed at an onshore location (e.g., water treatment facility, sewage collection system). In one embodiment, a portion of the pipeline secured to the sea floor near the first end passes through a durable buoy. In another embodiment, a portion of the pipeline secured to the sea floor adjacent the first end is integral with a durable buoy.

The systems and methods of the present invention generally include a wastewater inlet pump that directs incoming wastewater to a suitable treatment system (e.g., primary treatment system, secondary treatment system, tertiary treatment system). For example, if incoming wastewater is to be subjected to secondary treatment, a wastewater inlet pump pushes the wastewater to a secondary treatment component (e.g., one or more sequential batch reactors provided by Aqua-Aerobic systems, Inc.). As another example, if incoming wastewater is to be subjected to reverse osmosis, a wastewater inlet pump pushes the wastewater to a high pressure pump of the reverse osmosis system. The high pressure pump pushes the wastewater through a reverse osmosis membrane to treat or purify the wastewater, while microorganisms and other debris remain on the other side of the membrane.

The location on land is often referred to as a wastewater treatment facility and such a wastewater treatment facility may comprise a portion of a wastewater treatment facility in which only pretreatment and primary treatment are conducted. Alternatively, such a wastewater treatment plant may be a self-contained wastewater treatment plant, but without the steps associated with secondary treatment and final wastewater treatment being enabled. The received wastewater includes wastewater that has not been previously subjected to any treatment. The received wastewater also includes wastewater that has been previously pretreated and primarily treated onshore (e.g., a wastewater treatment facility). In such an embodiment, the wastewater entering the wastewater influent system may contain microorganisms corresponding to the secondary treatment of the wastewater.

The waste water received by the offshore facility is transferred from the offshore facility after having been suitably treated. This treated wastewater may be discharged into the body of water surrounding the offshore facility, transferred to a water carrier, or transferred to land. The treated wastewater transferred to land may be subjected to other treatments or distributed for irrigation or industrial applications. If suitably treated (e.g., reverse osmosis), the treated wastewater may also be transferred to land for human or animal use. Onshore distribution points and systems are described in detail in U.S. provisional patent application 60/564,921.

Referring again to fig. 1, the system of the present invention includes means for discharging treated wastewater from the vessel 10 (fig. 1) through a water outlet in communication with the body of water surrounding the vessel 10. The water outlet may include one or more discharge ports 40 mounted in the hull 11 of the vessel 10 through which ports 40 treated wastewater is discharged into the body of water 30 surrounding the vessel 10. The vent 40 may be mounted in the hull 11 of the vessel 10 such that the vent 40 is physically located above or below the water line of the vessel 10. The apparatus may further include a pump for increasing the water pressure of the wastewater before discharging the treated wastewater through the discharge port 40.

In the present invention, the offshore wastewater treatment facility may include a mixing system in communication with the wastewater treatment assembly and means for discharging treated wastewater from the wastewater treatment vessel. The mixing system mixes the wastewater with water directly from the surrounding body of water prior to discharging the treated wastewater. Such a system can dilute and/or cool the treated wastewater prior to discharging the treated wastewater into the surrounding body of water. The mixing system may include a mixing tank with a water inlet, a water outlet, a mixing intake system including a water inlet and a pump, a set of baffles, and a mixing grate having a plurality of apertures. Water is injected from the mixing intake system (i.e. water from the body of water surrounding the offshore facility) and the treated wastewater flows through the mixing grid and is mixed before flowing into the means for discharging the wastewater from the offshore facility. The size, shape and number of apertures may be selected to optimally mix the treated wastewater with water from the body of water surrounding the offshore facility. The slits reduce turbulence of the fluid flowing through the mixing grid. The mixing grid extends from one side of the mixing tank to the opposite side. Adjacent partition plates are connected to opposite sides of the mixing tank, respectively. The baffles are arranged in a staggered relationship such that a portion of each baffle overlaps an adjacent baffle. The fluid flowing through the mixing grid must travel a convoluted path before reaching the treated wastewater discharge system.

In another embodiment, the mixing system comprises a mixing basin with a treated wastewater inlet, a treated wastewater outlet, a mixing intake system comprising a water inlet and a pump, and any device capable of forming a substantially homogeneous mixture of treated wastewater and water from the body of water surrounding the offshore device. Examples of such equipment include high-speed stirring mixers and static mixers.

In certain embodiments, the treated wastewater is transported to a water carrier or onshore facility, rather than discharged into the body of water surrounding the offshore wastewater treatment facility. The present invention thus provides a means of transferring treated wastewater from the offshore facility to another vessel (e.g. a transport vessel such as a tug boat, tanker ship) or to an onshore facility. The system 200 shown in FIG. 2 generally includes a vessel 10 having one or more wastewater treatment modules 20a, 20b, 20c, 20d, and means for transferring treated wastewater from the vessel 10 to an onshore facility 140 (e.g., a wastewater treatment or distribution facility 80). If the offshore facility is located on water remote from the shore, as shown in FIG. 2, the system 20 of the present invention preferably includes a single pipe 120 (e.g., a floating, subsea pipe), but may also include multiple pipes for discharging the treated wastewater from the vessel 10 and transporting the wastewater to another vessel or onshore facility. In certain embodiments, the apparatus comprises a carrier vessel (e.g., a tugboat-towed barge or a converted single or double hull tanker). In the system shown in FIG. 3, the treated wastewater is transferred by a conveyor 50 in communication with the vessel 10 and the onshore facility 140. Conveyor 50 is configured to transport the treated wastewater to a transport vehicle 220 (e.g., a truck), which transport vehicle 220 then transports the treated wastewater to a location 140 on land; or the conveyor 50 directly transports the treated wastewater from the wastewater treatment vessel 10 to a location 140 on land. Any suitable means may then be used to transport the treated wastewater to a location 140 on land. The words "onshore," "above-ground," "shoreside," and "onshore" mean that the system or structure is primarily or wholly mounted on the ground 130 or on the shore 130.

In embodiments where the treated wastewater is transferred from the offshore wastewater treatment facility to a carrier vessel (e.g., a transport vessel or shuttle vessel), the treated wastewater is typically transferred between the offshore wastewater treatment facility and the transport vessel using a transfer pipe. The transfer pipe communicates a treated wastewater storage tank in the offshore wastewater treatment facility with a treated wastewater storage tank inside the transport vessel. To facilitate the transfer of the treated wastewater between the offshore wastewater treatment plant and the transport vessel, a support vessel may be used if desired. Typically, during transfer of treated wastewater between an offshore wastewater treatment facility and a transport vessel, both may be in motion relative to shore, or both may be moored or anchored. The offshore wastewater treatment facility can continue to produce treated wastewater during the transfer.

The sludge obtained in the wastewater treatment may be treated and stored in an offshore wastewater treatment plant. In the system shown in fig. 4A, a sludge treatment assembly 280 removes and treats sludge collected during wastewater treatment. In one embodiment, the sludge is transferred to a digester (which may be located on the offshore wastewater treatment facility, on another offshore facility, or on the ground). Aerobic and anaerobic digestion techniques are used in digesters to break down the organic constituents of the sludge. This digestion stabilizes the sludge and reduces odors. To kill pathogenic organisms, the sludge may be treated with corrosive chemicals or ultraviolet light. After treatment, the sludge may be discharged into the environment, for example, into the body of water surrounding the offshore wastewater treatment facility, or deposited on land. Sludge can also be used as a fertilizer. To facilitate processing, the quality of the sludge may be reduced by dewatering, for example, using a belt filter compressor to remove water from the sludge and produce a non-liquid cake.

The present invention provides a means for removing sludge from an offshore wastewater treatment facility for the purpose of discharging or transporting the treated sludge. For example, in the embodiment shown in fig. 2 and 3, the treated sludge 275 is transferred from the wastewater treatment vessel 10 to the sludge treatment/distribution facility 300 using a tugboat towing barge 70. In FIG. 3, as another example, treated sludge 275 is transferred from the wastewater treatment vessel 10 to a sludge treatment/distribution system 300 using a conveyor 50.

In certain embodiments, the treated sludge may be discharged from the offshore wastewater treatment facility into the surrounding body of water. In these embodiments, the means for removing sludge from an offshore wastewater treatment facility comprises a discharge for treated sludge. The discharge of the treated sludge may be of any configuration that communicates the sludge treatment assembly with the body of water surrounding the offshore wastewater treatment facility. If the treated sludge is discharged into the body of water surrounding the offshore wastewater treatment facility, it is preferred to dilute the sludge with water in the body of water surrounding the offshore wastewater treatment facility prior to discharge. The sludge may be mixed with the water in the body of water surrounding the offshore wastewater treatment facility in a manner similar to that described above for mixing the treated wastewater with the water in the body of water surrounding the offshore wastewater treatment facility.

Referring again to fig. 1, in the system 20, the wastewater (or sewage) is collected in a sewage collection system 60 (located on the surface 130) and then transferred to a pretreatment module 200 where the pretreatment module 200 is cleaned of streaks, sand, grit, etc. The treated wastewater is then transported to the wastewater treatment vessel 10 through a pipeline 120. After entering the water intake chamber 320 on the vessel 10, the wastewater is directed to the wastewater treatment assemblies 20a, 20b, 20c, 20 d. The wastewater is subjected to one or more wastewater treatments in these wastewater treatment modules to produce treated wastewater and sludge 275. The wastewater after treatment is diluted with water in the body of water surrounding the vessel 10 before being discharged from the wastewater treatment vessel 10. This may be accomplished by a hybrid system that communicates the wastewater treatment device with the device for removing wastewater in the vessel 10. The mixing system comprises a water inlet 39 for taking water from the body of water 30 around the vessel. The water inlet 39 has a plurality of apertures through which water from the body of water 30 surrounding the vessel 10 is drawn. After mixing, the treated wastewater is discharged through water outlets communicated with the water around the ship. The water outlet is provided with a discharge port 40 installed in the hull 11 of the vessel 10, and the treated wastewater is discharged into the water body 30 around the vessel 10 through the discharge port 40. Sludge from the wastewater treatment process is discharged from the vessel 10 and transferred to a location 140 on land by a tugboat towed barge 70. The transport vehicle 220 is used to transfer the sludge 275 from the barge 70 being towed by the tug boat to the location 140 on the land.

The embodiment shown in FIG. 2 is similar to that of FIG. 1, but in FIG. 2, the treated wastewater is transferred by conduit 121 to a location 140 (water treatment or distribution system 80) on land instead of discharging the treated wastewater out of the body of water 30 surrounding the vessel 10. The embodiment shown in figure 3 is similar to that shown in figures 1 and 2, but the vessel 10 is located offshore of the near quay rather than further on the surface. Wastewater enters the vessel 10 and is discharged from the vessel in the same manner as the system of figure 2. The treated wastewater is transferred to a wastewater treatment and/or distribution facility 80. In this embodiment, the resulting sludge is transferred from the wastewater treatment vessel 10 to the sludge treatment/distribution facility 300 using the conveyor belt 50. At the sludge treatment/distribution facility 300, the sludge is dumped or further processed. The sludge 275 may be transported from the apparatus 300 to another destination for use in agriculture or industry, for example, by transport cart 220.

Referring to fig. 4A, fig. 4A shows a cross-sectional view of a wastewater treatment vessel 10 having primary, secondary, and advanced treatment components. The wastewater treatment vessel 10 receives wastewater through an intake chamber 320 in communication with the first conduit 120. The wastewater then enters a primary treatment settling or settling tank 230 where undissolved solids are removed. The wastewater then enters a secondary treatment bioreactor 240 where microorganisms absorb the organic matter and nutrients in the wastewater. After several hours of suspension, the microorganisms settle to sludge 275. A portion of the sludge 275 is removed and transported to a sludge treatment assembly 280 for treatment and then discharged from the vessel 10; while another portion of the sludge remains in the secondary treatment bioreactor 240 for treatment of additional wastewater. The wastewater then enters a secondary treatment tank 260 for further secondary treatment. From here, the wastewater enters a final treatment tank 270 for disinfection. At this time, the treated wastewater may be discharged from the vessel through the discharge chamber 340 and the pipe, and transferred from the wastewater treatment vessel 10 to the onshore facility 140 for disposal or distribution. The treated wastewater may also be discharged from the vessel 10 into the surrounding body of water 30 through a discharge outlet 40 as shown in fig. 1. Alternatively, the treated wastewater in the final treatment tank may be subjected to a third stage treatment using chemicals in the chemical feeder 250. After advanced treatment of the wastewater, it may be discharged from the vessel 10 into the body of water 30 surrounding the vessel 10 or through a discharge chamber 340 into a pipeline 120 for transfer to land-based facilities 140 for disposal or distribution.

Referring to fig. 4B, fig. 4B shows a side cutaway view of the wastewater treatment vessel 10 with a secondary treatment assembly. The wastewater has been pretreated and primarily treated on the ground or in another water carrier to remove large solids, suspended solids and grease from the wastewater. The wastewater treatment vessel 10 receives wastewater through an intake chamber 320, the intake chamber 320 being in communication with the first conduit 120. The wastewater then enters the bioreactor 240 where separate mixing and aeration devices subject the contents of the reactor (i.e., microorganisms and wastewater) to biomass conditioning and nutrient reduction (i.e., removal of organic matter and nutrients from the wastewater) through alternating aerobic and anaerobic periods. After settling at rest, the wastewater is transported from the reactor to a first microfiltration unit 350 with a 10 micron fabric filter. The wastewater was filtered as it passed through the 10 micron fabric layer. The filtered wastewater is collected in a central pipe that directs the wastewater to a feedwater line that flows into the second microfiltration unit 350. The wastewater enters a second microfiltration unit 350 where a lower positive pressure passes the wastewater through a plurality of 0.1 micron membranes, rejecting fine particles larger than 0.1 micron. The water filtered through the membrane is directly extracted from the top of the second microfiltration unit 350 and discharged from the ship 10 through the discharge chamber 340. This treated wastewater may be discharged into the body of water 30 surrounding the vessel 10, or it may be transferred to land 140 for other treatment (e.g., reverse osmosis), distribution, or disposal.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. The scope of the invention is, therefore, indicated not by the illustrated embodiments but by the appended claims and their equivalents.

Claims

1. An offshore wastewater treatment vessel, wherein the offshore wastewater treatment vessel is located at the surface of a body of water, comprising:

a hull;

a wastewater treatment system at least partially installed in the hull, the wastewater treatment system capable of treating at least 2000 kiloliters of wastewater per day, producing an end product comprising sludge and treated wastewater; wherein the wastewater treatment system comprises a wastewater treatment assembly selected from:

a primary treatment system for reducing the suspended solids or grease content of the wastewater;

a secondary treatment system comprising bacteria capable of reducing the content of organic matter contained in the wastewater;

a sterilization treatment system including a device for killing microorganisms;

a nutrient removal system including a device for removing nutrients including nitrogen and phosphorus in wastewater;

a wastewater inlet in communication with the wastewater treatment system;

a water outlet for transferring treated wastewater from the vessel; and

a mixing system for mixing at least one end product with water in a body of water, the mixing system comprising a mixing tank located on the processing vessel and a water inlet and a water outlet.

2. An offshore wastewater treatment vessel as claimed in claim 1 wherein the wastewater treatment system comprises a primary treatment system for reducing the suspended solids or grease content of the wastewater.

3. An offshore wastewater treatment vessel according to claim 1, wherein the wastewater treatment system comprises a secondary treatment system comprising bacteria capable of reducing the content of organic matter contained in the wastewater.

4. An offshore wastewater treatment vessel as claimed in claim 1, characterised in that the wastewater treatment system comprises a disinfection treatment system comprising means for killing micro-organisms.

5. Offshore wastewater treatment vessel according to claim 1, characterized in that the wastewater treatment system comprises a nutrient removal system comprising means for removing nutrients including nitrogen and phosphorous in the wastewater.

6. An offshore wastewater treatment vessel as claimed in claim 1, characterised in that the wastewater treatment system comprises at least two of the following:

a sterilization treatment system including a device for killing microorganisms;

a nutrient removal system including a device for removing nutrients including nitrogen and phosphorous in wastewater.

7. An offshore wastewater treatment vessel as claimed in claim 1, characterised in that the wastewater treatment system comprises at least three of the following systems:

a sterilization treatment system including a device for killing microorganisms;

8. The offshore wastewater treatment vessel of claim 1, wherein the wastewater treatment system comprises:

a sterilization treatment system including a device for killing microorganisms;

9. The offshore wastewater treatment vessel of claim 1, further comprising a sludge treatment system.

10. The offshore wastewater treatment vessel of claim 9, wherein the sludge treatment system comprises a means for removing moisture from the sludge.

11. An offshore wastewater treatment vessel as claimed in claim 9, characterised in that the sludge treatment system comprises a disinfection system comprising means for killing micro-organisms.

12. The offshore wastewater treatment vessel of claim 1, further comprising a power generation facility.

13. The offshore wastewater treatment vessel of claim 1, further comprising a propulsion system to move the offshore wastewater treatment vessel.

14. A wastewater treatment facility located in a body of water remote from an onshore wastewater collection system, the wastewater treatment facility comprising:

(a) a wastewater treatment assembly capable of treating at least 2000 million liters of wastewater per day, the wastewater treatment assembly selected from the group consisting of:

a sterilization treatment system including a device for killing microorganisms;

(b) means for transferring wastewater from an onshore wastewater collection system to the wastewater treatment facility;

(c) means for transferring treated wastewater from said wastewater treatment facility;

(d) means for transferring sludge from said wastewater treatment facility;

wherein neither the means for transferring treated wastewater from the wastewater treatment facility nor the means for transferring sludge from the wastewater treatment facility discharges sludge or treated wastewater into a body of water.

15. The wastewater treatment facility of claim 14 wherein the means for transferring wastewater from the onshore wastewater collection system to the wastewater treatment facility comprises a pipeline.

16. The wastewater treatment facility of claim 14 wherein the means for transferring wastewater from the onshore wastewater collection system to the wastewater treatment facility comprises a ship.

17. The wastewater treatment facility of claim 14 wherein the means for transferring treated wastewater from the wastewater treatment facility comprises a pipe.

18. The wastewater treatment facility of claim 14 wherein the means for transferring treated wastewater from the wastewater treatment facility comprises a ship.

19. A wastewater treatment facility located in a body of water remote from an onshore wastewater collection system, the wastewater treatment facility comprising:

(a) at least a first wastewater treatment assembly and a second wastewater treatment assembly, each assembly capable of treating at least 2000 kiloliters of wastewater per day, the assemblies selected from:

a sterilization treatment system including a device for killing microorganisms;

(d) means for transferring sludge from said wastewater treatment facility.

20. The wastewater treatment plant of claim 19, wherein the first and second modules treat wastewater differently.

21. The wastewater treatment plant of claim 19, wherein the first and second modules are separated by a body of water.

22. The wastewater treatment apparatus of claim 21, further comprising a conduit that transports wastewater from the first assembly to the second assembly.