HK1074431B - Method for treating bodies of water or the sediments thereof - Google Patents

Description

Technical field

The invention relates to a process for maintaining or restoring an environmentally sound (natural) oxygen content in waters such as harbour basins, bays, lakes, rivers and canals, and in particular to a process for the environmentally sound treatment and, where appropriate, displacement of sediments present in such waters.

Background to the invention

The introduction of nutrient-rich wastewater into standing and flowing waters as a result of industrialisation, dense settlement and intensive agricultural use can change the species composition of the water biozones.

The ecological consequences of eutrophication include the development of algal masses formed by green and blue algae. They reduce the penetration of light into the water bodies and, for example, cause the loss of photosynthetically active macrophytes at the water table. Algal mass developments in surface water can lead to short-term oxygen saturation as a result of the photosynthetic activity of phytoplankton. However, the excess oxygen is reabsorbed (mainly at night) so that the degradation of organic substances (minerals) even leads to oxygen deficiency, as a consequence of a concentration of oxygen in the liquid in the atmosphere, as a result of the intense concentration of oxygen in the liquid, for example, the oxygen consumption in the atmosphere increases significantly.Err1:Expecting ',' delimiter: line 1 column 819 (char 818)

Once an aquatic organism has entered the vicious cycle of eutrophication and subsequent oxygen deprivation, it recovers only extremely slowly on its own.

The problem is also raised in the summer by water temperatures. The solubility of oxygen in water is temperature dependent and leads to a decrease in the oxygen concentration in the summer. Ecologically functional waters are thus vulnerable to measures that further reduce the oxygen concentration and can thus be a trigger for, for example, fish deaths.

It is clear that oxygen content is crucial to the ecological balance of a body of water.

Sediments form at the bottom of almost all bodies of water, such as in the bottom of harbours, in shallow bays, in lakes and in rivers, and in most cases in more or less strong mud and silt layers, which contain large proportions of sedimented suspended matter. Here, too, material is deposited, which is made up of dead organic biomass, which is either formed in the water itself or introduced directly into the water by wastewater. There, a biological degradation of this material takes place. The degradation takes place aerobically under oxygen consumption, if sufficient oxygen is present, but anaerobically, if oxygen deficiency prevails.

Err1:Expecting ',' delimiter: line 1 column 76 (char 75)

Such sediments may need to be relocated, removed or treated for a variety of reasons: in ports, busy rivers and canals, a certain water depth must be maintained, requiring regular removal of sediment layers; polluted or highly contaminated sediments are a hazard to the water body above them and must be cleaned or completely removed.

The sediments are usually anaerobic, depending on the organic content and other water conditions. As long as these sediments are deposited as a solid, compact layer separated from the water body above, the exchange of substances between the sediment and the water body above is low. If these sediments are loosened or even completely stirred due to the above measures and thus come into contact with the water body above, the oxygen is consumed by the immediate onset of oxidative degradation from the water body. This process is called oxygen consumption. The main sources of oxygen are: (1) instantaneous oxygen intake (mainly sulphide intake), (2) biological oxygen intake and (3) nitrogen oxidation.This is a short-term oxygen depletion (period in minutes to about 3 hours) from the water - usually by chemical oxidation of inorganic reducing ions. The sulfide digestion is very fast, since sulfide has no substance next to dissolved oxygen. At low oxygen content, the hydrogen sulfide is oxidized to elemental sulfur, whereas at excess oxygen to sulfur dioxide.The reduced nitrogen compounds, such as ammonium, are oxidized to nitrate by nitrite.

Whether this oxygen intake is significantly damaging depends on local conditions, but mainly on the dissolved oxygen load in the body of water and the oxygen-consuming properties of the sediment. Normally, the body of water above the reloading sediment is so large that it holds enough oxygen for the oxidation processes to occur that oxygen reduction is often small or not measurable. However, there are also often situations where the oxygen content of a water body is critical due to natural, biological toxicity and low solubility due to elevated temperatures, so that improper treatment of sediment can lead to significant oxygenation and sometimes to the loss of oxygen, for example, in the case of fish oil, which is important, in addition to other remedial measures, to the contamination of water already damaged by oxygen.

To avoid the unwanted effects of sediment treatment, the first step is to perform a precise analysis of the oxygen-absorbing behaviour of the sediments lying in the sediment, and then to assess this in relation to the water state. For example, sediments can be tested for their oxygen-absorbing effect by the Sensomat system of the company Aqualytic. The measurements are based on pressure difference measurements. In this case, the sample vessel containing the sediment sample is used at a constant temperature, with a proportional underpressure. The pressure difference is measured and stored by means of IR-sensors depending on the time. The chemical and biological oxygen consumption of hydrides is detected by the rapid rate of oxygen depletion during the period of the oxygen supply. The problem is measured at a speed of 10 - 52Pa.

If, on the basis of preliminary studies, it is found that a planned sediment treatment is problematic in terms of oxygen supply, it must be omitted or carried out in a particularly environmentally friendly manner.

In the past, experiments have been carried out with gaseous oxygen from the air and pure gaseous oxygen to increase the oxygen content.

DE 4416 591C1 describes a process in which the sediment is lifted up as a sediment suspension by means of a compressed air conveyor tube, then cleaned and fed back into the water. The purpose of the process is to prevent the sediment from spreading into the water outside the working area by means of flexible aprons. The disadvantage of the process is that large suspension clouds (excavator water) can form, which can drift apart and need to be carefully protected from distribution into open water.

Err1:Expecting ',' delimiter: line 1 column 82 (char 81)It is important that, unlike conventional sediment treatment methods, the sediment layer is retained as such, i.e. separated from the water body above it, and the suspension cloud has only a relatively small extent. If the ground below it has a corresponding slope, the suspended sediment layer can drain according to gravity. Alternatively, if no slope is present, it can be pumped off or allowed to be deposited again, where it is transferred back to a solid sediment layer. If a slope exists and the suspended layer is not to drain, hydrological measures can be taken to prevent a drainage.

DE 19756582 describes a process using the process described above in EP 0 199 653B1. In addition, diluted gaseous ozone is subsequently introduced into the suspended sediment layer during water injection or in a second operation. The ozone, which then dissolves in the sediment water, can break down oxidatively toxic metal-organic compounds. The disadvantage is that the ozone must first overcome considerable diffusion barriers before it can have its oxidative effect in the sediment water.The ozone is a powerful oxidizer, which is toxic to animals such as fish and can harm the organisms that live in the water. To make more effective use of ozone, several operations must be performed, with ozone being introduced from below into the suspended sediment layer. The injection bar is carried under the previously suspended sediment layer, with gas outlets directed upwards.However, through gas bubbles escaping the suspended sedimentary layer, ozone is also introduced into the water body and, as already mentioned, can be harmful there and is lost to oxidative degradation in the suspended sedimentary layer.

Against this background, the invention is intended to provide a method which allows, without the disadvantages of known methods, to effectively maintain or, if necessary, restore the oxygen concentration in water in an ecological equilibrium.

In particular, the purpose of the invention is to prevent the harmful absorption of oxygen during the transfer of water sediment and thus to provide an environmentally friendly process which allows the treatment, transfer or dredging of sediment at any time of the year and at any scale

Further functions and advantages of the invention are described below.

Description of the invention

The above tasks can be solved by the method described in independent claim 1, specific embodiments are given in the subclaims.

The invention relates to a process for the treatment of water or its sediments, whereby water is introduced into the sediment in which an environmentally compatible oxidizer or a mixture of several suitable oxidizers is dissolved, essentially without the introduction of gaseous constituents into the sediment, whereby the sediment to be treated is suspended and remains as a suspended sediment layer separated from the water body of the vessel, and the amount of oxidizer or the mixture of oxidizers is selected in such a way as to substantially prevent the effusion of water-damaging oxygen from the water body into the suspended sediment layer.

This involves the oxidizer or oxidizer mixture being formed directly in the water taken from the environment for injection (primary water for injection) before injection to produce the secondary water for injection.

Environmentally friendly or suitable oxidizers or mixtures thereof within the scope of the present invention are all oxidizers that meet the environmental requirements and fulfill the purpose of the present invention, which is to essentially prevent the harmful diffusion of oxygen from the water body into the suspended sediment layer.

Brief description of the drawings

Fig.1:Schematic representation of a preferred embodiment of the invention with a pressure reactorFig.2:Schematic representation of an alternative preferred embodiment of the invention with a tube reactorFig.3:Schematic representation of a preferred embodiment of the tube reactorFig.4:Increase in specific input energy with increasing oxygen concentration in water.

Detailed description of the invention

The conventional water injection method (WI method) according to EP 0199 653B1 can be used for the method of the present invention, which increases the sediment layer by gently increasing its volume and making it fluid.

An advantage of this known sediment treatment method according to EP 0 199 653B1 is that it avoids mixing the sediment with the water body and maintains the suspended sediment layer as a separate reaction chamber. Oxygen can only be released from the water body into the suspended layer by slow diffusion - the reaction site - as convective rapid transport of matter is avoided by avoiding intense mixing.

However, in order to eliminate the oxygen-consuming substances present in the sediment and to avoid oxygen consumption as far as possible, the suspension of the sediments with water is carried out according to the invention by dissolving an environmentally compatible oxidizing agent.

The oxidizing agent is introduced in water, which is 100% dissolved, and is immediately present in the sediment water, which is available in the reaction chamber where the oxidative decomposition is to take place. A reaction chamber is thus formed, separated from the rest of the water body, and at the same time an oxidizing agent is introduced for oxidative decomposition.

In addition, the incorporation of the oxidizer in the sediment layer in a dissolved form prevents the formation and release of gas bubbles from the sediment layer, thus avoiding the agitation of the sediment layer, which is inevitable when air, ozone, O2 or other substances enter the water body in the gaseous state and which causes the unwanted oxygen intake in the water body.

As an alternative to the mobile injection method described in EP 0199 653B1, injection systems can also be installed permanently in water bodies, and in water bodies subject to locally recurrent oxygen deprivation, such as those in front of weirs, such a system that is permanently available on demand may be desirable.

The amount of oxidizing agent applied is generally chosen to be at least sufficient to compensate for the predetermined (unavoidable) oxygen-consuming effect of the sediment and to set the oxygen concentration to a level that at least avoids a concentration gap between the suspended sediment layer and the water body. The compounds to be oxidized in the suspended sediment layer are thus rapidly broken down and no concentration-related oxygen diffusion from the water body occurs.

According to the invention, the substances present in the sediments and leading to oxygen intake (immediate oxygen concentration, biological oxygen intake and nitrification), such as organic compounds or hydrogen sulfide, ammonia and ammonium compounds, are chemically and biologically degraded by the oxidizing agent or combination of the oxidizing agents used.

The oxidizer or oxidizer mixture may be dissolved in water in various ways and then fed into the sediment.

The oxidizer is dissolved directly in the primary water for injection to form the secondary water for injection without intermediate formation of the reactant water; in addition, the oxidizer or the mixture of oxidizers can be dissolved in high concentration in water. The reactant water thus formed is then mixed with the water taken from the surrounding area for injection (primary water for injection) to obtain the secondary water for injection containing the oxidizer. This is injected into the sediments.

Reactive water can also be injected into the sediment layer separately from the primary or in addition to the secondary injection water and thus in locally higher concentrations. Injecting secondary injection water and additional reacting water separately, the secondary injection water and the reacting water may contain either the same or different oxidizers. The intake of oxidizers can be controlled in a targeted manner, thus avoiding an overdose which may lead to an undesirable entry into the body of water. In the case of stronger oxidizers, such as ozone or hydrogen peroxide, which could be harmful to the ecosystem of the body of water, it is desirable. The accurate addition of the oxidizing agent in the form of a solution also leads to the selection of undesirable doses of the suspended gases, which can only be done without the use of undesirable sediment.

According to the present invention, to produce secondary water for injection, a sufficient amount of oxidizer or oxidizer mixture is dissolved directly in the primary water for injection to produce the secondary water for injection, which is then injected into the sediment layer according to the known injection method.

The same water-bed may be treated once or several times in succession; in the case of heavy pollution, intermittent deposition and re-suspension with water for injections may be necessary.

Mixtures of different oxidizers are also possible. The use of ozone or hydrogen peroxide can be advantageous when higher oxidation power is required, e.g. when the sediment layer is heavily loaded with organic compounds or even toxic metal-organic compounds. An entry of the strong oxidizers ozone and hydrogen peroxide into the water bodies can be avoided by precise dew as described above.

The advantages of the water injection method according to EP 0 199 653B1 such as slow drainage of the suspended sediment layer or pumping can be fully exploited. The suspended sediment layer treated in accordance with the invention can also be deposited again, which then remains in place as purified sediment or can, if desired, be drained by conventional excavation methods without the risk of oxygen consumption. Drainage can also be prevented by appropriate hydraulic measures.

The reaction water in which the oxidizer or the oxidizer mixture is dissolved in a sufficiently high concentration is either produced directly on the water injection vessel in situ during the treatment of the water or on land and then placed in storage tanks on the water vessel. Preferably, production is carried out directly on the water vessel.

In the case of permanently installed injection systems, the reaction water system shall be installed nearby and adapted to local conditions.

Pure elemental oxygen is preferred as an oxidizing agent.

In principle, the preferred method using oxygen as an oxidizing agent is to introduce highly enriched oxygen dissolved in water into water or sediment.

The following is a description of the physical basis of the dissolved oxygen entry and of the preferred devices for technical implementation, and the shipbuilding implementation of these devices.

Physics of the oxygen supply:

In order to compensate for the immediate oxygen intake (mainly from sulphides) which may be particularly harmful in conventional or conventional WI dredging, an adequate amount of oxygen must be supplied to the sediment, preferably by a WI process modified in accordance with the invention, which introduces an adequate amount of oxygen into the suspension cloud (suspended sediment layer) produced by the conventional WI process, with the following objectives: The limited suspension cloud produced by the WI process is not dispersed, for example, by the flotation of rising gas bubbles.The chemical reaction of oxygen with sulphide takes place mainly in the suspension cloud.The impact number determining the reaction rate is relatively large due to the spatial proximity of the reaction partners sulphide and oxygen.Oxygen diffusion from the surrounding body of water is largely avoided.Oxygen intake can be dosed by bypass depending on the speed of the vessel and the flow of oxygen-saturated water.

Physical laws: Dalton's law:

According to Henry Dalton's law, the following law applies to the solubility of gases in water:

Equation 1:

$c_s={H_i}^{T}x{p}_i$ Other The concentration of the active substance in the feed additive shall be calculated as follows: Hi: Henry constant of the gas in pure water (g/m3 bar) : pi partial pressure of the gas i (bar abs)

The Henry constant is temperature dependent. The also existing slight dependence of the Henry constants on pressure and salinity in water can be neglected for practical calculations. Tabelle 2: Werte der Henry-Konstante bei verschiedenen Temperaturen für N₂, O₂ und CO₂

Temperatur [°C]
0	29,0	68,7	3340,9
5	25,7	60,2	2771,1
10	23,0	53,6	2324,5
15	20,8	48,2	1970,0
20	19,1	43,7	1693,6
25	17,7	40	1470,9
30	16,6	36,9	1281,7

The Henry constant or O2 saturation concentration of pure oxygen at a partial pressure of 1 bar is, for example, 48.2 g/m3 at 15°C.

The parial pressure of a gas is generally:

Equation two:

$p_i=p_{\mathrm{ges}}{\mathrm{x\; y}}_i$ Other : pi partial pressure of the gas i (bar abs) pges: total pressure (bar abs) Yi: volume of the gas i

Nitrogen, oxygen and carbon dioxide are contained in the air at the following volumes: Other

:	=	0,78	=	78 %
:	=	0,21	=	21 %
:	=	0,0003	=	0,03 %

The sum of the partial pressures of the individual gas components is equal to the total pressure pges.

The partial pressure of oxygen in the air is therefore only 0.21 bar at a total pressure of 1 bar and 0.78 bar for nitrogen. $c_{\mathrm{SL}}={H_{O_2}}^{10}{\mathrm{x\; p}}_{\mathrm{ges}}{\mathrm{x\; y}}_{O_2}=53,6x1x0,21=11,3\left(g,/,m^3\right)$

The maximum saturation concentration according to equation 1 for air nitrogen, air oxygen and carbon dioxide in air at a total pressure of 1 bar abs and a water temperature of 15°C is given in Table 3: Other Tabelle 3: Sättigungswerte von N₂ O₂ und CO₂ der Luft in Reinwasser bei 15 °C und 1 bar abs.

		[bar]
Luftstickstoff	20,8	0,78	16,2
Luftsauerstoff	48,2	0,21	10,1
	1970,0	0,0003	0,6

Thus, when air is introduced into water, for example by fine-blowing at the bottom of a basin, the maximum oxygen concentration is 15°C at water temperature, as shown by the equation. $C_{\mathrm{SL}}=48,2x1x0,21=10,10g/m^3\mathrm{zu\; erreichen}!$

When pure oxygen is used instead of air, the oxygen concentration attainable at the same limit conditions (pressure and temperature) is 4.8 times higher, since the oxygen content in pure oxygen is 100%, and therefore the partial pressure of oxygen pi is equal to the total pressure pges (100 %: 21 % = 4.8). Other

allgemein:

reiner Sauerstoff:

The saturation values of atmospheric oxygen are compared to those of pure oxygen in Table 4: Other Tabelle 4: Sättigungswerte von Luftsauerstoff und reinem Sauerstoff in g/m³ bei 1 bar abs in Abhängigkeit von der Wassertemperatur

Temperatur [°C]	0	5	10	15	20	25	30
Luftsauerstoff	14,4	12,6	11,3	10,1	9,2	8,4	7,8
Reinsauerstoff	68,7	60,2	53,6	48,2	43,7	40	36,9

This is illustrated by a case example: Other

Wassertemperatur	15 °C
02-Konzentration im Rohwasser
Betriebsdruck des O2-Reaktors	0,5 bar ü = 1,5 bar abs

According to Henry Dalton's law, an O2 output concentration from the oxygen reactor of 48.2 x 1.5 g O2/m3 = 72.3 g/m3 should be possible. However, since N2 and CO2 are also dissolved in the raw water and the O2 entry into the water is accompanied by an outgassing of N2 and CO2 from the water, there will be no more 100% O2 atmosphere in the gas phase of the reactor.

The reactor therefore produces a discharge concentration of: $c_{{\mathrm{SO}}^2}={H_{O^2}}^{15}{\mathrm{x\; p}}_{\mathrm{ges}}{\mathrm{x\; y}}_{O^2}=48,2x1,5x0,65=47,0\left({\mathrm{g\; O}}_2,/,m^3\right)$ Other The Commission has reached a

The higher saturation concentration of pure oxygen also results in a higher rate of dissolution or a lower energy consumption for oxygen intake.

The first Fick's law of diffusion is intended to explain these advantages.

The first law of diffusion:

The law of Henry Dalton states which O2 saturation concentrations are in equilibrium with the gas phase. For the application of reactive dissolved oxygen, the rate at which the oxygen is dissolved in water is decisive. In the stationary case this is described by Fick's first law of diffusion:

Equation three:

$\mathrm{dQ}/\mathrm{dt}=K_D\mathrm{x\; A\; x\; dc}/\mathrm{dx}$

The quantity of oxygen recorded per unit time dt is then proportional to the contact surface A between the O2 concentration differences dc/dx in this contact layer (phase boundary layer).

The proportionality factor KD is called the diffusion constant and is essentially dependent on the water temperature for the water/oxygen system.

Optimisation of the amount of oxygen dQ recorded per unit time dt can be achieved over a large exchange area A as follows: by distributing the water in the oxygenated gas phase as finely as possible (e.g. by a borehole or similar circuit breaker in the pressure reactor) high concentration differences dc/dx at the contact points between water and gas phase, by constant replacement of the exchange vessels by means of pumps or blowers, by high partial pressure of oxygen in the gas phase and by the high oxygen saturation concentration associated with it, by low oxygen concentration in the water, by rapid and high oxygen uptake after exit from the reactor,

The following relation applies to the differential expression dc/dx: $\mathrm{dc}/\mathrm{dx}=\left(c_S,-,c_X\right)/\delta$

The cS is the saturation concentration determined by the partial pressure of oxygen in the gas phase, and the cX is the measurable oxygen concentration in the water. δ is the thickness of the phase boundary layer on the liquid side. A high partial pressure of oxygen therefore results in a large concentration difference in the boundary layer, dc/dx. This is particularly true if the concentration cX is kept small by distributing the oxygen in the gas phase and by consumption processes (e.g. bacterial decomposition).

A high concentration difference causes a large intake of oxygen per unit time, as shown in equation 3, resulting in a low specific intake energy.

The specific input energy of any input device for air or pure oxygen is shown in Figure 4.

In order to dissolve as much oxygen as possible in water, the dissolving process is preferably carried out in a pressure reactor. $\mathrm{p\; x\; V}=\mathrm{n\; x\; RT}$

This results in a doubling of the dissolved gas volume from constant volume and a doubling of pressure, i.e. instead of about 44 mg O2/l 88 mg O2/l could theoretically be dissolved at 2 atmospheres under the condition of ideal gases. The possible pressures to allow an optimal oxygen intake must be determined for each specific case. In theory, conventional pressure reactors, such as those supplied by Linde, can record oxygen at 6 atmospheres. This means a theoretical oxygen intake of about 260 g O2/m3.In order to avoid the dissolved oxygen in the water being returned to the gas phase, an optimal pressure must be determined for the optimum amount of oxygen to be dissolved at each step. This optimum pressure depends, inter alia, on the water pressure into which the oxygenated water is introduced. Since in the preferred embodiment the water enriched with dissolved oxygen (reactive water) is mixed with the injection water (primary injection water) in the injection beaker before relaxation to form the secondary injection water (primary injection water), a concentration decrease of the highest oxygen concentration is obtained. Consequently, a concentration decrease occurs between hydrogen enriched with oxygen (reactive water) and injection water (injected water) which is diluted according to the degree of oxygen dissolvation in this range.so that, under the given pressure conditions, namely water pressure + injection pressure, early exhaust is avoided as far as possible.

The effect of the instantaneous intake in the suspension cloud on the exhaust gas of the dissolved oxygen is also reduced, and the extent to which this effect allows for a higher oxygen intake must be determined on a case-by-case basis.

The oxygen transfer by bubbles into water is also important in the process of dissolving oxygen in water (see Robert F. Mudde: Oxygen transfer from bubbles into water, Delft University of Technology, 26.06.2002).

The Reynolds number tells you the current state.

Physically, the boundary layer observation of longitudinally flowing walls (bubble walls) is essential. $K_R=\mathrm{\eta \; x\; F\; x\; dv}/\mathrm{dz}\left(N\right)$ $DynamischeViskosität\eta =f\left(p,T\right)\left(N,,s,/,m^2\right)$

The thickness of the boundary layer is essential for the oxygen transfer. $D_x=3,02\mathrm{x\; X}:\left({\mathrm{Re}}_x\right)½\left(m\right);=3,02{\left(\mathrm{\eta \; x\; X},:,\left(\mathrm{\rho \; x\; \upsilon }\right)\right)}^{0,5}=3,02\mathrm{x\; X}:{\left(\mathrm{Re}\right)}^{0,5}\left(m\right)$

The pressure drop in pipes, fittings and reactors favors the absorption of dissolved oxygen, since the higher pressure required allows for the absorption of increased amounts of oxygen. $\mathrm{\Delta p}=\mathrm{\lambda \; x\; L}/\mathrm{d\; x}0,5\mathrm{x\; \rho \; x}{v}^2\left(N,/,m^2\right)$

The solution of oxygen is mainly in the turbulent range, which means that for a pressure reactor to be constructed, it is preferable to install current disruptors to increase the oxygen solution.

The following technical specifications:

The tank tank with liquid oxygen should be at least 10 days in size and preferably fixed on land. The tank can also be transported by truck to various places of operation. The liquid oxygen can be withdrawn by tube to the watercraft. It is preferable to fill the tank with a transport tank which should be opened for about 1 day. The transport tank should be lifted onto the watercraft, installed there in accordance with the relevant regulations and installed at the appropriate dimensioned safety vapour. The vapour is removed by means of a tube up to the watercraft. The necessary temperature is not to be lost in the operation of the vapour, and the vapour is not to be converted into ice.

The measurement and control technique once regulates the oxygen flow to the reactor and also includes a pressure relief valve. The control values are taken before and after the reactor and set in a ratio controller.

A commercially available pressure reactor can be used, and a preferred embodiment is a tube reactor (Figure 2).

Figure 3 shows possible dimensions of a suitable pipe reactor. These dimensions are designed for smaller quantities of reactive water. The specialist knows how to dimension larger systems. This pipe reactor is designed for 50 m3 per hour. The length of the pipe is approximately 15 m. The diameter of about 150-200 mm is calculated so that for the flow of 50 m3/h the flow time is 12-20 sec. The pipe reactor has on the flange power interrupters that are intended to increase the turbulence.

A slide which can be adjusted from above must be installed on the other open end of the pipe.

For example, the resulting reaction water is fed to the primary injection water by the O2 water pump as shown in Figure 1. The resulting secondary injection water is fed to the sediment via the injection beams. Preferably, the reaction water is produced in a tube reactor as shown in Figure 2 and mixed at the end of the tube reactor with the primary injection water to produce the secondary injection water. Preferably, the tube reactor is rearranged along the connection between the water vehicle and the injection ball in a space-saving manner. This is done by preferably placing the raw water mixer at one end of the reactor, which leads to a secondary injection pool at the other end of the injection pool and releasing the oxygen from the water pump for the hydrogen. The oxygen is then injected into the water at the end of the reactor, which is then heated to the raw water before the injection pool is connected to the water pump. The oxygen is then injected into the water at the other end of the reactor, which is then heated to the raw water before the oxygen is released from the water pump.

Alternatively, the reaction water can be introduced separately into the sediment by means of a secondary tube (second injection beam) specially placed parallel to the main injection tube (injection beam), via its own injection nozzles.

Furthermore, the oxygen to form the secondary reaction water can be dissolved directly in the primary injection water without intermediate reaction water formation.

Any injection of water with an oxygen concentration higher than that of water taken from the water is according to the invention.

The oxygen concentration of the secondary injection water is limited only by the fact that exhaust gas bubbling must be avoided as far as possible during injection. Furthermore, it is limited by the oxygen concentration of the reactant water, because the pressure in the reactor necessary for oxygen concentration of the reactant water must be within a technically feasible range. An upper numerical limit for oxygen concentration of the secondary injection water cannot be stated here, however, because this is due to the technical possibilities available in each case and, on the other hand, to the oxygen concentration of the reactant water to be treated, the acidity concentration of the secondary water due to the extreme acidity of the water and the concentration of the sedimentation material in the water before the oxygen concentration of the reactant water is reached.

If the oxygen content of the body of water is to be increased without treatment of the sediment, e.g. to compensate for oxygen deficiency in fish carcasses, the oxygenated water may be supplied directly to the body of water. For this purpose, the injection bar is to be passed at a suitable distance over the sediment. This distance should be at least such that the sediment is largely unchanged in its state (e.g. no suspension). The injection bar may then be brought to the surface at any distance, but it must be brought as close as possible to the sedimentation in order to achieve an oxygenation of the sediment-bearing deep water layer.

The amount of oxygen required per unit time and the rate of injection will determine the oxygen concentration of the secondary injection water and the amount of secondary injection water required per unit time. The oxygen concentration of the secondary injection water will determine the amount and oxygen concentration of the reactant water and the ratio of the reactant water to the primary injection water. The amount of reactant water needed per unit time and the concentration of reactive oxygen to be obtained at the time of injection will determine the properties of the reactive oxygen. The actual oxygen production conditions can also be determined by measuring the reactor temperature and conditions of operation.

The method of the invention described above preferably introduces at least 10 kg of O2 per hour, preferably at least 20 kg of O2 per hour and most preferably at least 30 kg of O2 per hour into the water; it may also introduce more than 50 kg of O2 per hour or preferably more than 60 kg of O2 per hour or, particularly preferably, between 60 and 100 kg of O2 per hour into the water; in special embodiments, more than 100 kg of O2 per hour may be introduced.

The ozonation of the injection water is carried out in the same way as the loading of pure oxygen, but instead of the pure oxygen gas, oxygen gas enriched with up to 13% vol. ozone is added to the reactor. The reactor conditions and the percentage ozone content of the oxygen gas are adjusted to the desired concentration of ozone in the reaction water or secondary injection water by the mixing ratio. The desired ozone concentration varies with the water conditions and the purpose to be fulfilled.

Aqueous solutions of hydrogen peroxide may be stored in tanks on the vessel and dosed to the primary or secondary water for injection or to the reaction water in the desired quantities. The amount of hydrogen peroxide in the water for injection is adjusted according to the invention so that no significant entry is made into the water bodies. However, if a certain entry is required, for example to induce a bactericidal effect or to reverse algal mass development, the concentration of hydrogen peroxide may be adjusted accordingly. Otherwise, the procedure is carried out in a manner analogous to the introduction of oxygen, ozone or mixtures thereof.

The following example is intended to illustrate the above relationships and to demonstrate the efficiency of the process, but is not intended to be a limitation.

The starting conditions are 8 g/m3 oxygen in the ambient water and 20 °C water temperature (possible influences of water contents are not taken into account). At a pressure of 1.5 bar of oxygen gas in the reactor, an oxygen concentration in the reactant water of about 43 g of oxygen per m3 of water is reached. Two reactors with a flow rate of 500 m3/h are used. The reactant water thus formed is mixed with the primary injection water in a mixture ratio of 1 : 8 . The secondary injection water thus formed has an oxygen concentration of about 12 g/m3 and is injected into the sediment at 1.5 bar overpressure and an injection rate of 9000 m3 per hour.

Further tests carried out by the notifiers showed that an amount of 60-100 kg O2 per hour could be supplied to the water, in addition to the naturally dissolved oxygen present in the primary water for injection, by pumping 8,000 m3 of secondary water for injection per hour over a 12 m long, bottom-running injection bar with 24 nozzles directed at the sediment lying on the bottom, at an excess pressure of about 1.5 bar.

Claims (17)

1. Method for treating bodies of water or sediments thereof, respectively, wherein water (secondary injection water) in which an environmental compatible oxidation agent or mixture of several suitable oxidation agents is dissolved, is supplied into the sediment, substantially without introducing gaseous components, wherein the sediment to be treated is suspended and is maintained as a suspended sediment layer separated from the water body of the body of water, and the amount of oxidation agent or mixture of oxidation agents is selected such that a diffusion of oxygen detrimental to the body of water from the body of water into the suspended sediment layer is substantially prevented, wherein the oxidation agent or the mixture of oxidation agents is directly dissolved in proximity of the water taken for injection purposes (primary injection water) in advance of the injection for the provision of the secondary injection water.
2. Method according to claim 1, wherein treatment of the sediments or the body of water is carried out from a water craft.
3. Method according to claim 1, wherein treatment of the sediments or the body of water is carried out from a stationary installed plant.
4. Method according to claims 1 to 3, wherein the oxidation agent or the mixture of oxidation agents is in advance dissolved in water (reactive water) and this reactive water is added to water taken from the environment (primary injection water) before injection for the provision of the secondary injection water, preferably within a bypass.
5. Method according to claims 1 to 3, wherein the oxidation agent or a mixture of oxidation agents is in advance dissolved in water (reactive water) and this reactive water is injected separate from the primary or secondary injection water into the sediment layer.
6. Method according to claims 1 to 5, wherein segment of the body of water is treated several times, consecutively.
7. Method according to anyone of claims 1 to 6, wherein the oxidation agent consists only of compounds of oxygen or oxygen and hydrogen, or is a combination thereof.
8. Method according to claim 7, wherein the oxidation agent or the mixture of oxidation agents is selected from the group, consisting of elementary oxygen (O₂), ozone (O₃) and hydrogen peroxide (H₂O₂).
9. Method according to claim 7, wherein the oxidation agent comprises oxygen (O₂).
10. Method according to anyone of claims 4 to 9, wherein the reactive water is generated in situ during the treatment of the sediment layer or the body of water.
11. Method according to anyone of claims 7 to 10, wherein the oxygen concentration of the reactive water corresponds at least to the concentration saturation at normal conditions and pure oxygen atmosphere.
12. Method according to anyone of claims 8 to 11, wherein the reactive water is produced in the reactor by dissolving the gaseous oxygen in water under oxygen pressure, and the water is taken from the environment and flows through the reactor.
13. Method according to claim 12, wherein liquid oxygen is transferred into the gas form by means of one or more vaporisers heated by air and is introduced into the reactor by means of one or more nozzles.
14. Method according to claims 8 to 12, wherein a mixture of gaseous oxygen and ozone is used.
15. Method according to claims 1 and 8 to 14, wherein an aqueous solution of hydrogen peroxide is dosed into the primary or secondary injection water or the reactive water.
16. Method according to anyone of claims 1 to 15, wherein the suspended sediment layer is allowed to flow of.
17. Method according to anyone of claims 1 to 15, wherein the suspended sediment layer is prevented from flowing of by means of technical water engineering measures.