RU2039713C1 - Method for performing anaerobic treatment of acid and neutral sewage - Google Patents

Abstract

FIELD: sanitary; environment protection. SUBSTANCE: method involves supplying sewage water into anaerobic reactor mixing sewage water portions discharged from the anaerobic reactor with unprocessed sewage supplying the so obtained mixture for its being treated in the presence of alkaline reagent in the anaerobic reactor. Carbon dioxide is removed from the mixture of the unprocessed sewage and sewage water from the anaerobic reactor by blowing through methane from the anaerobic reactor. The alkaline reagent is introduced into the mixture of the not processed sewage and sewage water from the anaerobic reactor. The proportions of sewage portions discharged from the anaerobic reactor to those not processed is to be calculated from an equation shown in the patent application. EFFECT: enhanced effectiveness in removing oxygen- consuming impurities from sewage. 3 cl, 2 dwg

Description

 The invention relates to the treatment of wastewater or discharges in order to remove oxygen-containing contaminants before discharging wastewater into the environment.

 A number of industries form acid-containing wastewater. They may have a high organic content and are not suitable for discharge into a lake or river due to the high oxygen consumption associated with the discharge of wastewater. Environmental conservation laws, as well as regulations, set limits that limit the content of chemical and biological oxygen-consuming substances present in wastewater before it is released into natural gutters.

 In the anaerobic filtering process, wastewater is sent through an anaerbic reactor in which microorganisms in the anaerobic environment decompose organic matter in the wastewater and produce methane and carbon dioxide. The reactor is a substantially hermetically sealed tank, adapted to receive the flow of wastewater. The reactor may contain backfill material to which microorganisms can attach. Download may be arbitrary, such as packing rings, or oriented, such as backfill material, marketed under the trademarks Vinil Coro and Сoro-Z.

The design of the reactor can be divided into two types, based on the flow characteristics of the liquid contained in them. In an upflow reactor, wastewater usually flows from the bottom of the sealed reaction tank and moves upward. Methane and carbon dioxide also move up with the liquid and are released from the liquid phase into the gas phase as the gases approach the surface, as a function of pressure and separation difference coefficients. The final fluid is discharged from the top of the fluid level. The upper part of the tank defines a cased region, substantially free of gas collection liquid [1]
In a downflow reactor, wastewater usually flows from the top of the reactor and moves down. Methane and gaseous carbon dioxide move with the liquid in a downward flow. However, the movement of the liquid in the direction from top to bottom and a constant increase in pressure with increasing depth tend to trap soluble gases in the liquid and form an acidic buffer solution. The upper part of the tank defines a hood-covered area that is substantially free of gas collection liquid. In both systems, with both upward and downward flow, the stream leaving the anaerobic reactor passes through a degasser (vacuum chamber) and enters the sump. Methane gas is captured and used as an energy source. The precipitate formed in the process falls to the bottom of the sump and either returns to the process or is wrapped further for final placement [2]
The normal occurrence during the operation of reactors in the anaerobic process is the formation of carbon dioxide. Carbon dioxide formed in the anaerobic reaction creates a partial pressure, which causes the dissolution of carbon dioxide in the aquatic environment and the formation of carbon dioxide. The formation of carbonic acid, and in the case of the carbohydrate type of wastewater, the formation of acetic acid can cause a drop in the pH value in the reaction tank, requiring the addition of caustic soda to maintain the reactor at a normal operating pH of 6.8 or more. The lack of stabilization in highly concentrated wastewater creates a constant demand for caustic soda. The addition of caustic soda is the most expensive feature of the anaerobic process.

 The design of the downflow reactor may further contribute to the increase in acid conditions in the reactor. Continuous metabolism of organic material can contribute to the pH gradient in the tank. The areas towards the bottom of the reactor under the influence of pressure due to the depth of the liquid and without any means of removing carbon dioxide can have large concentrations of carbon dioxide.

 The problem of acid formation in the reaction tank is complicated if the incoming wastewater is acidic in itself. Indeed, some manufacturing processes may produce organic waste of limited solubility in the wastewater stream in which it is suspended. The preparation of terephthalic acid for use in the plastics industry results in wastes containing acetic acid, benzoic acid, terephthalic acid, isophthalic acid, orthophthalic acid, para-toluic acid, trimellitic acid, 4-carboxybenzaldehyde and hydroxymethylbenzoic acid. Some of these aromatic acids may be present in discharged streams at concentrations exceeding their solubility. If this is the case, aromatic acids can cause acidic intake and must be neutralized before they decompose. Arriving in a reactor having a low pH, aromatic acids can precipitate from solution, reducing the efficiency of the anaerobic process of metabolism of the organic components of the wastewater stream.

 Areas in the bottom of the high carbon dioxide reactor are potential sources of carbon dioxide removal base. If the contents of the reactor are stabilized to approximately neutral pH, the removal of carbon dioxide or carbon dioxide will contribute to the formation of a basic solution that can neutralize incoming acidic waste.

 Raw waste from many industrial processes is not suitable for biodegradation due to temperature limitations. In typical processes, industrial wastes are incubated in settling basins in order to have a constant source or reservoir for feeding the anaerobic process. Sludge tanks are further equipped with aeration equipment, including atomizers or turbulators, in order to cool the high-temperature raw waste from industrial processes to ambient temperature.

 A known method of anaerobic wastewater treatment, comprising mixing part of the water leaving the reactor with the source wastewater, introducing an alkaline reagent and feeding the mixture into the anaerobic treatment reactor [3] The ratio of the volume of wastewater and recycled solution 1: 1-20.

 Known methods and the closest analogue do not disclose methods and devices for anaerobic treatment of acidic waste of limited solubility, pH and temperature control. In the prototype method requires a large consumption of alkaline reagent caustic soda. In addition, there is a large release of hard-to-destroy waste into the environment.

 Compounds such as terephthalic acid, O-phthalic acid, benzoic trimellitic acid, etc. they have limited solubility in the aquatic environment and are extremely resistant to biodegradation, and it is difficult to destroy these resistant substances.

 The present invention characterizes a method and apparatus for reducing and controlling the concentration of acids in anaerobic flow treatment, enhancing the solubility of acidic components of limited solubility, and controlling the temperature of the waste entering the reactor.

 An anaerobic method for treating acidic or neutral wastewater, including the supply of wastewater to an anaerobic reactor, mixing part of the wastewater into an anaerobic reactor, mixing part of the wastewater leaving the anaerobic reactor, with the original wastewater, feeding the resulting mixture for treatment in the presence of an alkaline agent in anaerobic reactor. Carbon dioxide is removed from the mixture of feed wastewater and wastewater from the anaerobic reactor by blowing through a mixture of methane from the anaerobic reactor. An alkaline agent is added to the mixture of feed wastewater and wastewater from the anaerobic reactor.

где В отношение щелочи в анаэробной среде к кислоте в исходном сточной воде, Е фракция двуокиси углерода, образовавшейся в анаэробной среде, которая отводится в соответствии со следующей зависимостью:
E= 1-

+

где А кислотная нормальность в подаче необработанных сточных вод, Н_r концентрация водородных ионов в анаэробном реакторе, Н_s концентрация водородных ионов в десорбере, К_а константа равновесия органической кислоты, К_с константа равновесия угольной кислоты, К_h константа закона Генри для двуокиси углерода, n количество двуокиси углерода, моль, на эквивалент усвоенной органической кислоты, Х конверсия фракционной органической кислоты в анаэробной среде.The ratio of the specified part of the wastewater leaving the anaerobic reactor to the wastewater supplied to the stripper is determined in accordance with the equation:
Z

where In the ratio of alkali in the anaerobic environment to acid in the source wastewater, E is the fraction of carbon dioxide formed in the anaerobic environment, which is discharged in accordance with the following relationship:
E = 1-

+

where A is the acid normality in the supply of raw sewage, H _r hydrogen ion concentration in the anaerobic reactor, H _s hydrogen ion concentration in a stripper, K _and equilibrium constant of the organic acid, _K the equilibrium constant of carbonic acid, K _h Henry's Law Constant for carbon dioxide, n the amount of carbon dioxide, mol, per equivalent of digested organic acid; X is the conversion of fractional organic acid in an anaerobic environment.

 Thus, the method includes contacting a mixture of an organic substrate and a stream leaving the reactor with methane in a sealed volume. Firstly, methane obtained in the anaerobic process drives off carbon dioxide and then comes into contact with the combined organic substrate and the stream leaving the reactor. Carbon dioxide is distributed in gaseous methane. Both methane and gaseous carbon dioxide are suitable for further processing.

 The invention facilitates the removal of gaseous carbon dioxide from a mixture of an organic substrate and a stream leaving the reactor. Its implementation is characterized by contacting the effluent from the reactor, rich in carbon dioxide, coming from the industrial process waste, which have a temperature exceeding the ambient temperature. The increased temperature of the atura facilitates the removal of carbon dioxide, releasing it from the mixture.

 Mixing a low-temperature effluent from the reactor with high-temperature industrial effluents (waste) gives a mixture with an intermediate temperature. A further decrease in the temperature of the mixture is achieved by bringing the mixture into contact with a substantially inert gas. In a closed system, the gas may include methane obtained as a reaction product of an anaerobic process. However, a closed system is not necessarily required in all applications.

 A method for controlling the temperature of waste entering an anaerobic reactor includes an operation in which a mixture of an organic substrate and a stream leaving the reactor can be brought into contact with a substantially inert gas by suitable means, including spraying the mixture in the presence of air. The mixture is passed through a series of flow turbulators in the presence of air and sparging air through the mixture. The temperature of the mixture is controlled by increasing or decreasing the number of contacts of the inert gas with the mixture.

 Preferably, the gases used to distill off carbon dioxide or to cool the hot waste fed to the reactor do not participate in anaerobic processes, do not readily enter solutions, and do not react with the substrate in a manner that makes the substrate difficult to biodegradable.

 An embodiment of the invention includes the distillation of carbon dioxide from a mixed reactor charge with methane carbon dioxide. First, methane gas and carbon dioxide are separated by removal of carbon dioxide by a method known to those skilled in the art, such as pressure in the presence of water or the addition of caustic. Next, methane is brought into contact with the effluent to remove carbon dioxide. The methane-carbon dioxide mixture is suitable for further use in a process including recycling for stripping carbon dioxide or for use as an energy source.

 To implement the invention, a device is used to reduce or control the concentration of acid during anaerobic treatment of the stream, to enhance the dissolution of acidic components with limited solubility, and to control the temperature of the waste entering the reactor.

 A device is used having an anaerobic reactor adapted for anaerobic digestion of an organic substrate in a process that forms gaseous compounds capable of dissolving in a liquid. The anaerobic reactor is further provided with receiving means, including pipelines for introducing an organic substrate into the reactor. The reactor also contains discharge means, including pipelines for removing wastewater from the reactor. The device contains a desorber-dissolver connected to the receiving and unloading means of the reactor. The desorber-dissolver is adapted to receive incoming wastewater and effluent from the reactor and bring the stream into contact with an inert gas to allow dissolved gaseous compounds to disperse in the inert gas. The desorber-dissolver in combination with the receiving means of the reactor is adapted to discharge the mixture of the outgoing and incoming flow into the reactor.

 The implementation of the invention provides a method and apparatus that reduce the consumption of caustic soda to maintain a working pH in anaerobic treatment of the stream. Caustic consumption can be reduced by 40-60%. The carbon dioxide content in the exhaust gases is reduced from about 30 to 20% without negative impact on the anaerobic process.

 Particularly suitable for carrying out the invention are downflow reactors, which tend to accumulate or create a difference in carbon dioxide, due to pressure and fluid flow. Part of the effluent from the reactor from the bottom of the reactor is shunted into the desorber-dissolver.

 The desorber-dissolver contains a capacious reservoir having receiving means for the flow coming from the anaerobic reactor. The tank is equipped with discharge means to remove the outgoing stream from the tank. The reservoir includes means for receiving gas, through which a substantially inert gas enters the reservoir. The tank is equipped with means for displacing gas and liquid, which communicate with means for receiving gas and / or means for receiving the effluent from the reactor, for example, a spray gun communicating with means for receiving the effluent from the reactor, a gas-aeration system including a blower and ventilation ducts connected with means for receiving gas, a stone channel for air or gas associated with means for receiving gas. The stone channel is immersed in the stream leaving the reactor and is located in the tank. The flow turbulators are connected to means for receiving the effluent from the reactor, which increase the degree of contact with the gas entering the reservoir.

 The desorber-dissolver is equipped with means for receiving waste, including pipelines that are adapted to mix the waste with the effluent from the reactor to increase the solubility of the substrate as carbon dioxide is removed from the effluent.

 The reactor also includes methane recovery means, and a desorbing dissolver of methane receiving means associated with gas supply means for use in stripping carbon dioxide from a stream leaving the reactor.

 The invention is suitable for controlling the temperature of the wastewater stream entering the reactor and facilitates the carbon dioxide stripping. Thus, the contacting effluent from the reactor with the waste stream effluent entering the reactor having an elevated temperature tends to distill carbon dioxide from the downward stream and lower the temperature of the mixture. In addition, close contact of the mixture of effluent and incoming wastewater with an inert gas allows the mixture to cool significantly, this can be controlled by the degree of contact between the gas and the liquid. Cooling can be increased with increasing current through the desorber-dissolver.

 The characteristics of the invention are particularly suitable for downstream reactors, which may have high concentrations of carbon dioxide in the lower (bottom) regions of the reactor. Downstream reactors tend to remove carbon dioxide in the effluent from the reactor, so that methane formed in the anaerobic process is more valuable as an energy source. An open carbon dioxide stripping system from the downstream is also characterized by evaporation functions that can reduce the liquid volume of the wastewater stream.

 Figure 1 presents the system of anaerobic wastewater treatment.

 The anaerobic wastewater treatment system includes two main components: anaerobic reactor 1 and desorber-dissolver 2.

 Anaerobic reactor 1 receives a wastewater charge from desorber-dissolver 2 via line 3. The discharge may include organic acids such as carboxylic acids, ascorbic acid, acetic acid, propionic acid, acrylic acid, glycolic acid, maleic acid, adipic acid, benzoic acid , butyric acid, valerianic acid, hydrochloric acid, glyceric acid, succinic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, tert-butylphthalic acid y, pyromethyllitic acid, 1,2,4,5-benzenetetracarboxylic acid and phenylindanedicarboxylic acid, as well as other organic alcohols, ketones, esters, aldehydes and phenols. Organic acids entering the reactor may have limited solubility.

 These acidic organic substrates taken by the reactor are metabolized by bacteria, including bacilli, various strains of staphylococci, etc.

 During anaerobic digestion of organic materials in a reactor, a consortium of bacteria produces methane and carbon dioxide. Carbon dioxide is able to interact with water to form carbon dioxide.

 Reactor 1 is a substantially sealed tank. The reactor 1 is formed by a vertical cylindrical wall 4, a bottom 5 and a floating vaulted collector 6.

 The floating vaulted manifold 6 is part of the gas collection system 7. The floating vaulted manifold 6 is a truncated cone in shape having radially chamfered down surfaces 8. The outer radial edge of the floating vaulted manifold 6 extends vertically, forming a vertical flange 9, which seals in contact with the inner a cylindrical wall 4. The vertical flange 9 rests in the protrusion 10 of the interfitting connection, which continues radially upward from the cylindrical wall 4.

 Methane gas formed during the anaerobic digestion of organic materials in the reactor flows upward through the aqueous solution contained in the tank and is collected in the hollow space defined by the floating vaulted gas manifold 6. The floating vaulted gas manifold 6 is capable of changing its volume by moving upward along the cylindrical wall 4, providing additional volumes for methane gas.

 Methane gas in the floating vaulted gas collector 6 communicates with the compressor 11 via a pipe 12 and a distribution valve 13, which are part of the gas recovery system 7. The system 7 includes a distribution valve 13, which communicates with a safety torch 14 via a pipe 15. A safety torch 14 allows you to burn excess methane .

 Inside the anaerobic reactor contains filling material 16 having a significant surface area for attachment and growth of the bacterial consortium. Such an environment may include randomly oriented materials, such as packing rings, or oriented material, such as bundles or blocks of polyvinyl plastic under the trademarks Vinil-Coro and Coro-Z. The backfill material 16 is held on the reactor frame 17, providing a free space 18 for collecting a substantially purified stream leaving the reactor.

 Wastewater enters the reactor 1 through means for receiving wastewater, including a conduit 3 leading to the reactor and a distribution network 19, which distributes the incoming wastewater substantially uniformly through the upper region of the filling material. Thus, the incoming wastewater is introduced into the upper part of the backfill material 6, passes through the backfill material 16 downward, allowing anaerobic batteries attached to the backfill material 16 to exchange and digest the organic substrate brought in with the aqueous solution. Wastewater continues to flow through the reactor 1 down to the hollow region 18 and is removed from the reactor by means of loading means including a conduit 20 for the effluent from the reactor.

 Part of the effluent from the reactor leaves the reactor through line 20 and pipe 21, which separates the effluent from the reactor and directs it in two ways. One path represented by conduit 22 leads to further processing operations or to release into the environment. By way of example, but not limitation, conduit 22 may supply the effluent from the reactor to an aerobic-type biosystem to completely decompose residual organic material. The aerobic biosystem may also include further operations using sludge trapping pools or the like.

 The second path, represented by pipeline 23, leads part of the effluent from the reactor to the desorber-dissolver 2. The effluent from the reactor 1, flowing through conduit 23, is enriched in carbon dioxide.

 In general, the decomposition of aromatic acids does not lead to significantly lower pH values in the reactor than wastewater entering the treatment, since carbon dioxide is formed as the aromatic acids decompose. The operation limiting the intensity of the decomposition of aromatic acids is the initial operation, leading to the destruction of the structure of the rings. No noticeable increase in other acidic intermediates or by-products is observed.

 Conversely, the decomposition of wastewater loaded with carbohydrate leads to a decrease in pH in the reactor compared to new waste coming in. A higher acid concentration in the treated wastewater can be explained by a number of factors. Wastes of the carbohydrate type are essentially neutral, and complete metabolism causes the production of an acid-forming substance of carbon dioxide. The initial decomposition of carbohydrate proceeds quickly and leads to intermediate compounds that are subject to slow metabolic processes. These intermediates may include acids such as acetic acid.

 Desorber-dissolver 2 uses a stream leaving the reactor 1, which is stabilized by carbon dioxide at about pH 7, as a neutralizing agent for acidic waste. In one embodiment, part of the effluent from reactor 1 is directed to a stripping dissolver 2. The stripping dissolver 2 is adapted to receive the effluent from the reactor and bring it into contact with an inert gas.

 The desorber-dissolver 2 includes a reservoir 24 suitable for receiving liquid, including a stream coming from reactor 1. Means for bringing the effluent from the reactor into contact with an inert gas include a sprayer 25, an aerator 26, and a series of step flow turbulators (not shown).

 The atomizer 25 communicates with the reactor 1 through pipelines 20 and 23. The atomizer 25 is adapted to receive liquid and disperse the liquid in an inert gas in the reservoir 24. The aerator 26 is adapted to receive an inert groove and disperse the gas in the liquid, including the stream contained in the tank exiting the reactor 24. The aerator 26 is connected to the blower 27 through a turbo 28.

 A blower can pump atmospheric air, however, in a closed system it may be more advantageous to feed the aerator 26 with methane through pipelines (not shown) connected to the gas trapping system 7. When methane is used as an inert gas, the aerator is connected to a compressor 11 and a carbon dioxide stripper. Carbon dioxide can be distilled from methane or other gases by various methods, including compressing the gas mixture in the presence of water by a method known in the art, or by adding caustic soda.

 The desorber-dissolver 2 includes means for venting gases from the reservoir 24, including valve 29. In an open system, valve 29 can be opened to the atmosphere. In a closed system, valve 29 is coupled to methane collecting system 7 of reactor 1 by suitable means, including pipelines (not shown).

 The effluent from the reactor comes into contact with an inert gas in the desorber-dissolver 2. Carbon dioxide introduced by the effluent from the reactor is distributed in the gas phase, increasing the pH of the residual liquid. Residual liquid can be discharged from the stripper-dissolver 2 using a discharge pipe 3 for further processing, including returning the liquid to the reactor 1.

 An embodiment of the present invention includes a desorber desolver 2 adapted to receive fresh industrial waste. The pipe 23 leading to the desorbing dissolver 2 includes a pipe 30 for receiving fresh industrial waste from the supply pipe 31. The supply pipe 31 may be directly connected to the industrial process or may receive wastewater from a settling tank. To facilitate the displacement of fresh waste with the stream leaving the reactor, the pipe 23 includes a linear mixer 32.

 A mixture of fresh waste and the effluent from the reactor is taken up by the desorber-dissolver 2, which removes carbon dioxide and increases the pH of the mixture. In the case when the mixture contains aromatic acids of limited solubility, increasing the pH of the mixture promotes the transition of solids into solution.

 It will be appreciated by those skilled in the art that fresh waste can be mixed with the effluent from the reactor prior to removal of carbon dioxide or after removal of carbon dioxide. However, if the fresh waste has a higher temperature than the stream leaving the reactor, mixing the fresh waste with the stream leaving the reactor to remove carbon dioxide facilitates the stripping of the carbon dioxide evolution.

 For example, if the pH of the incoming waste from the industrial process for producing tereflalic acid can be 4.0-4.5 and the pH of the stream coming from the reactor can be about 7.0, then the pH of the mixture leaving the desorber-dissolver 2 in the reactor 1 ranges from 6 , 0 to 7.7, i.e. the mixture is largely neutral.

+

Z

P

где А нормальность кислоты в поступающих сточных водах;
В отношение основания в реакторе и кислоте в поступающих сточных водах; В может быть выражено как отношение концентрации ионов натрия в реакторе к концентрации кислоты в поступающих отходах;
К часть двуокиси углерода, полученной в реакторе, которая отводится в десорбере-диссольвере;
Н_r концентрация ионов водорода в анаэробном реакторе;
Н_s концентрация ионов водорода в десорбере-диссольвере;
К_а константа кислотного равновесия в сточных водах;
К_с константа равновесия углекислоты;
К_h константа закона Генри для двуокиси углерода;
n двуокись углерода, полученная на эквивалент дигерированной кислоты, моль;
Р равновесие парциального давления двуокиси углерода газа в десорбере-диссольвере;
Х фракционированное превращение кислоты в реакторе;
Z отношение исходящего из реактора потока к потоку свежих сточных вод в десорбере-диссольвере.Assuming that the gas and liquid phases in the reactor 1 and in the desorber-dissolver are in equilibrium, a mathematical model of the operating characteristics of the desorber-dissolver can be described as follows:
E = 1

+

Z

P

where A is the normality of the acid in the incoming wastewater;
In relation to the base in the reactor and the acid in the incoming wastewater; B can be expressed as the ratio of the concentration of sodium ions in the reactor to the concentration of acid in the incoming waste;
To the part of the carbon dioxide obtained in the reactor, which is discharged in the desorber-dissolver;
H _{r the} concentration of hydrogen ions in the anaerobic reactor;
H _{s is the} concentration of hydrogen ions in the desorber-dissolver;
K _{a is} the acid equilibrium constant in wastewater;
K _{c is} the equilibrium constant of carbon dioxide;
K _h Henry's law constant for carbon dioxide;
n carbon dioxide obtained per equivalent of digestion acid, mol;
P equilibrium of the partial pressure of carbon dioxide gas in the stripper-dissolver;
X fractionated acid conversion in the reactor;
Z is the ratio of the effluent from the reactor to the flow of fresh wastewater in the stripper-dissolver.

 Figure 2 presents the operating conditions necessary to achieve specific removal of carbon dioxide.

The ratio Z of the effluent from the reactor to the fresh wastewater stream in the dissolver-desorber 2 to the P-equilibrium of the partial pressure of carbon dioxide in the desorber-dissolver 2 is plotted for different values of the E fraction of the obtained carbon dioxide, which is discharged in the desorber-dissolver 2. The relationships shown in FIG. 2 are based on wastewater containing acetic acid as the main component with K _a equal to 1x10 ^-4.76 , A 0.08 n, B 0.1277, H _r 1x10 ^-7 mol, K _s 1x10 ^-6.46 , K _h 1x10 ^-1.57 m / atm, n 1.66, X 0.85.

 The point values in FIG. 2 are the pH values for the stripper at specific Z and E. Losses of methane at higher E values suggest that lower E values between 0.25 and 0.50 are favorable. Thus, a preferred recirculation ratio of from about 1 to 6, and more preferably from 1.5 to 4.0.

Removing carbon dioxide from a portion of the reactor effluent and mixing the distilled stream with fresh wastewater supplies reduces caustic requirements by 20–40%
The invention allows to control the temperature of the mixture of the effluent from the reactor and fresh wastewater. For example, the wastewater temperature industrial process for producing terephthalic acid may be in the range of 55-60 ° ^C. The temperature of the liquid entering the reactor is desired ≈ 38 ^° C

 Mixing waste water and fresh waste coming out of the reactor causes a drop in temperature. A further decrease in temperature occurs as a result of contacting the liquid in the desorber-dissolver with an inert gas. Indeed, atmospheric air can be purged through desorber-dissolver 2 through aerator 26, if required to reduce the temperature of the mixture of fresh and effluent from the reactor. Temperature control in the desorber-dissolver makes other devices and operations unnecessary, including sprayers in pools to withstand the upper flow from reactor 1, unnecessary.

 The preferred embodiment of the desorber-dissolver 2 for an open system is consistent with the design of a tower refrigerator adapted to receive a mixture of the effluent and the effluent stream. The preferred cooling tower is the Y-series tower refrigerator, model T1000 manufactured by Baltimore Aircool.

 The invention allows the introduction of nutrients and caustic means, if required to control the pH and provide microorganisms in the reactor 1 with additional growth factors. Nutrients and caustic agents are fed through pipelines 33 and 34, connected to the discharge pipes 3 from the desorber-dissolver 2.

 The pipeline for supplying steam 35 in thermal contact with the discharge pipe 3 of the desorber-dissolver is adapted to heat the pipe 3 and its contacts to provide further thermal control of the temperature of the material entering the reactor 1.

 The invention provides a system of sensors for regulating and monitoring the operation of valves, pH values, temperature, flow, material and liquid level in a system operating in a manner known to those skilled in the art.

 Also provided are pumps and compressor equipment for moving liquids and gas by methods known to the person skilled in the art.

Claims (3)

 1. METHOD FOR ANAEROBIC TREATMENT OF ACID OR NEUTRAL WASTE WATERS, including the supply of wastewater to the anaerobic reactor, mixing part of the wastewater leaving the anaerobic reactor, with the source wastewater, feeding the resulting mixture for processing in the presence of an alkaline agent into an anaerobic reactor, that carbon dioxide is removed from the mixture of feed wastewater and wastewater from the anaerobic reactor by blowing methane from the anaerobic reactor through a mixture of methane.  2. The method according to claim 1, characterized in that an alkaline agent is introduced into the mixture of source wastewater and wastewater from the anaerobic reactor. 3. The method according to claim 1, characterized in that the ratio of the specified part of the wastewater leaving the anaerobic reactor to the original wastewater is determined in accordance with the equation

where A is the normality of the acid in the source wastewater;
B the ratio of alkali in anaerobic environment to acid in the source wastewater;
E is the fraction of carbon dioxide formed in an anaerobic environment, which is discharged in accordance with the following relationship:

,
where H _{r the} concentration of hydrogen ions in the anaerobic reactor;
H _{s the} concentration of hydrogen ions in the stripping solvent;
K _{a is} the equilibrium constant of an organic acid;
K _{c is} the equilibrium constant of angular acid;
K _h Henry's law constant for carbon dioxide;
n the number of moles of carbon dioxide formed per mole of equivalent of the digested organic acid;
X conversion of fractional organic acid in an anaerobic environment.

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