Abstract: The dewatering of sludge is improved by utilizing a water-soluble cationic copolymer in the aqueous phase of a water-in-oil emulsion wherein the copolymer has been prepared by (i) preparing an aqueous solution of a non-ionic monomer and a portion of the cationic monomer, (ii) emulsifying the aqueous solution in a hydro-carbon oil to form a water-in-oil emulsion, (iii) adding the balance of the total intended cationic monomer to the emulsion while substantially no polymerization is occurring, and (iv) polymerizing the monomers.

Abstract: A process for disposing of sanitary sewage sludge by producing a pumpable slurry of sewage sludge with or without solid carbonaceous fuel and burning said slurry as fuel in a partial oxidation gas generator, furnace, or boiler. The aqueous slurry of sewage sludge is concentrated by removing water by means of a conventional belt filter press, centrifuge, or hydroclone. The dewatered slurry of sewage sludge is heated by direct contact with steam while air and organic vapors are simultaneously removed, to reduce the pressure in the system; hydrothermally treated in two steps with indirect and direct heat exchange with steam; dewatered by flash evaporation and centrifuging; and burned with or without admixture with solid carbonaceous fuel in a partial oxidation gasifier, furnace, boiler, or incinerator to produce synthesis gas or a hot raw effluent gas stream. In a preferred embodiment, the effluent gas stream is cleaned and purified and non-contaminating ash and slag are separated.

Abstract: An anaerobic digestion process for sewage sludge comprises a first step of dewatering the raw sewage sludge to provide a solids content therein of at least 10 weight %. A portion of digested sludge resulting from methane fermentation is recirculated and added to the dewatered raw sludge, the weight ratio of digested sludge to dewatered raw sludge being at least 1:1. The resulting mixture is homogeneously kneaded and then subjected to methane fermentation. At least one of the dewatered raw sludge prior to the recirculating step and the kneaded sludge mixture during methane fermentation is subjected to thermal treatment at a temperature not less than 50.degree. C.

Abstract: A container capable of dewatering wet mixtures and for transportation which comprises (1) an external cylindrical container with openings therein having a hanging member in an upper portion thereof, wherein the hanging member can shut the upper portion of the external cylindrical container, and wherein the external cylindrical container has an easy to open and shut closure at a bottom portion and (2) an internal porous container for dewatering a wet mixture is described. This container permits dewatering, packing, storing and transporting operations to be easily achieved.

Abstract: A method for treating wastewater sludge so that a stability based upon achieving a significant microbial population, conductivity level and percent solids, is developed rapidly, is provided for indefinitely and is independent of climatic conditions. A dewatered sludge that has not been treated (i.e., raw) or a sludge that has been treated to a PSRP level or a sludge that has been treated to a PFRP level, i.e., pasteurized or sterilized sludge when still in a wet condition, i.e., between 12%-30% solids, or when in a dry condition, i.e., between 30%-60% solids, is mixed with alkaline adsorptive materials to reduce odor, to increase the percent solids and to facilitate granulation, is adjusted to a mildly alkaline pH, and is adjusted to an ionic conductivity which will allow the sludge to mature rapidly when seeded with a beneficiating microbial flora. This process will reduce the pH of a high alkaline treated sludge, e.g., often above pH 12, to a physiological pH of between 7 and 9.

Abstract: Waste sludges containing up to 35% weight percent hydrocarbon contaminants and up to 50% weight percent inorganic materials are treated to induce acclimation of indigenous microbes present therein, the acclimated indigenous microbes thereby releasing extra-cellular enzymes capable of catalyzing hydrolysis of at least the hydrocarbon contaminants in the waste sludges. This step is pursued until a substantial increase of biological activity takes place in the waste sludges. Biological activity is allowed to continue at an increased rate until the hydrocarbon contaminants are substantially biodegraded.

Abstract: A method and apparatus for dewatering sludges and/or concentrating suspen and dissolved impurities in solutions by simultaneously freezing and rotating same. Rotation of the sludge is accomplished in a rotatable cylindrical apparatus capable of controlled rotational rate sufficient to continuously maintain a thin layer of water between suspended particulate impurities and an ice front which forms on inner cylindrical surfaces of the cylindrical apparatus. The ice front moves progressively inwardly to displace the suspended impurities toward the center of the cylindrical apparatus, thereby concentrating the sludge both by this displacement and by the removal of liquid water from the sludge. The concentrated sludge is discharged from the cylindrical apparatus when the rotation of said apparatus becomes insufficient to maintain the thin water layer between the ice/sludge interface.

Abstract: A device and method for preparing sludge for disposal comprising a box with a thin layer of gravel on the bottom and a thin layer of sand on the gravel layer, an array of perforated piping deployed throughout the gravel layer, and a sump in the gravel layer below the perforated piping array. Standpipes connect the array and sump to an external ion exchanger/fine particulate filter and a pump. Sludge is deposited on the sand layer and dewatered using a pump connected to the piping array, topping up with more sludge as the aqueous component of the sludge is extracted. When the box is full and the free standing water content of the sludge is acceptable, the standpipes are cut and sealed and the lid secured to the box.

Abstract: A method and product for sterilizing and drying waste products such as plant sludge, animal excrement and process wastes wherein the waste material is first settled or dewatered to a moisture content between 4% to 60% and then blended and reacted with alkaline earth metal oxides in the presence of an atmosphere of carbon dioxide, and in the absence of the oxygen. After the sludge is blended with the alkaline earth oxides, the carbon dioxide is removed so that air or oxygen will contact the blended constituents. A violent exothermic reaction takes place between the water in the constituents and the alkaline earth oxides causing a rapid rise in temperature of the constituents and thus sterilizing the constituents to produce a safe and useable end product.

Abstract: A process for disposing of sanitary sewage sludge by producing a pumpable slurry of sewage sludge and solid carbonaceous fuel e.g. coal, petroleum coke, rubber. The slurry is burned as a fuel in a partial oxidation gas generator, furnace, or boiler. In the process, an aqueous slurry of sewage sludge is concentrated by removing water by means of a conventional belt filter press or presses. The dewatered slurry of sewage sludge is hydrothermally treated and cooled and depressurized. The viscosity of the slurry of sewage sludge is reduced to less than about 2000 centipoise by shearing. The sheared sewage sludge is then ground together with a solid carbonaceous fuel to produce a pumpable slurry which is burned with a free-oxygen containing gas in a partial oxidation gasifier, furnace, boiler, or incinerator to produce a hot raw effluent gas stream. In a preferred embodiment, the effluent gas stream is cleaned and purified and non-contaminating ash and slag are separated.

Abstract: A process for disposing of sanitary sewage sludge by producing a pumpable slurry of sewage sludge and low grade solid carbonaceous fuel and burning said slurry as fuel in a partial oxidation gas generator, furnace, or boiler. The aqueous slurry of sewage sludge is concentrated by removing water by means of a conventional belt filter press or presses. Prior to and/or immediately after said concentrating step particles of low grade solid carbonaceous fuel e.g. lignitic coal, peat, wood and cellulose-containing materials are mixed with the slurry of sewage sludge. The dewatered slurry of sewage sludge and low grade solid carbonaceous fuel is hydrothermally treated in three stages and excess water is separated by flash evaporization and/or centrifuging.

Abstract: A paint sludge is subjected to aerobic biodegradation with increased dry content of the resulting sludge and the latter is then subjected to anaerobic biological degradation. The effluent from the two biostages are sterilized by ozonization, UV-irradiation or peroxide addition. The sludge from the anaerobic biostage can be dried to an inert granulate and drying vapors are recycled to the aerobic biostage. The sterile liquid is returned to the wash water circulation of the painting plant.

Abstract: A method for efficiently thickening and dewatering a slurry sludge in a short period of time without the necessity of a vast site, which comprises the steps of: stirring a slurry sludge added with a coagulant in a stirring tank to convert the slurry sludge into a floc; supplying the floc and a superantant liquid, which are produced in the stirring tank, onto an inlet side of an inclined endless travelling filter cloth of an endless travelling filter cloth type dewatering unit, which comprises a dewatering tank and the above-mentioned inclined endless travelling filter cloth arranged in the dewatering tank; continuously travelling the thus supplied floc, on the endless travelling filter cloth, toward an exit side thereof; thickening the floc on a portion of the endless travelling filter cloth, which portion is located in the supernatant liquid in the dewatering tank, and dewatering the thus thickened floc on a portion of the endless travelling filter cloth, which portion is located above the surface of the sup

Abstract: An in-vessel composting system wherein the exhaust gas from aerated compost feed material is pretreated by scrubbers and then by a chiller/condenser. A small portion of this cool, relatively dry, ammonia-free gas is passed through an activated carbon column and discharged to the atmosphere. The remaining portion of the exhaust gas is supplemented by ambient air to make-up for the volume of air vented and recirculated through the composting system until such time as the system requires a fresh supply of oxygen. The system is then recharged by blowing in ambient air and venting the spent recirculating air.

Abstract: An apparatus and method for stabilizing sludge such as the sludge produced by municipal waste water treatment plants includes thickening of the sludge to a dry solid content in the range of 3% to 8% before feeding it to at least one comparatively small reactor tank that extends horizontally and has an inlet and outlet adjacent opposite end walls. The system preferably utilizes multiple tanks stacked one above the other and connected in series. The tanks have an in-built mixer that sweeps through the interior of the tank. The mixer is eccentrically mounted so that its mixing members carry the sludge through the uppermost portion of the tank interior and are spaced from the bottom surface of the tank. A sparger is located either in the inlet or in the bottom clearance of the tank to introduce microscopic bubbles of oxygen and ozone into the sludge. A pressure regulating valve controls the flow of the stabilize sludge from the uppermost reactor tank.

Abstract: A method and a device for separating certain microorganisms from fecal matter are described. The method is effective in relatively fast detection and identification of bacterial pathogens in e.g. chicken feces, thus making it possible to diagnose certain diseases within a short period of time. The method comprises inducing the bacteria (microorganisms) containing matter through a sequence of basically non-absorbent screens with selected, gradually decreasing pore sizes. Factors important in optimizing the separation process are discussed.

Abstract: The present invention is concerned with a process for enhancing the dewaterability of a waste sludge having a substantial content of water-retaining cellular structure arising from microbiological action and having a solids content of at least fifteen percent by weight. The pH of the sludge is adjusted to 4.0 or less, the sludge is subjected to heat treatment to significantly enhance its filterability, the pH is again adjusted to near neutral, the sludge is subjected to a second heat treatment step, and the sludge is filtered to a final solids content in excess of about fifty-five percent by weight.

Abstract: The invention relates to a method for processing manure, comprising the steps of:i) adding an organic carrier liquid to the manure;ii) concentrating the mixture of manure and carrier liquid;iii) condensing the formed vapor;vi) anaerobic treating of the condensate; andv) aerobic treating of the effluent from the anaerobic treatment.Preferably the effluent deriving from the anaerobic treatment is denitrified in a denitrification unit and nitrified in a nitrification unit, and wherein a portion of the sludge-influent mixture from the nitrification unit is recirculated to the denitrification unit.The treating yield is greater than 90%, preferably greater than 95%, such as 97-99% BOD.

Abstract: Apparatus and process useful in the separation of undesirable organics from various types of compositions including sludge. The apparatus comprises a contactor vessel, a sludge conduit for conveying sludge to the contactor vessel, and a sludge cutter for reducing the sludge conveyed by the conduit to reduced cross-section extrudates for deposition in the contactor vessel. The sludge cutter includes a foraminous member and can operate to roughen the surface of the extrudates to provide increased surface area for contacting with solvent. The sludge cutter is arranged to effect free fall of the reduced cross-section extrudates from the sludge cutter for initiating breakup of the extrudates into reduced length segments. A deflector preferably is positioned in the path of the free-falling extrudates to promote further breakup of the extrudates into relatively short segments or pellets.

Abstract: The invention relates to the conditioning of liquid organic substances and biomass, particularly of municipal sewage sludge, with the help of chelating agents and enzymes, by breaking the organic substance down in an aerobic-conditioning reactor by addition of chelating agents and enzymes, this is discontinued prior to the complete dissolution of the organic matter after a time period of 0.5 to 20 hours. The mixture of substances is then subjected to an open-top non-aerated postreaction phase of 5 to 15 hours during which biogenous flocculation takes place. A solid-liquid separation follows.

Abstract: The invention relates to a process for anaerobically degrading highly concentrated process waste waters as obtained particularly in the chemical industry, in paper mills and cellulose plants, fish-processing plants, and in the production and elimination of alcohol or the like, whereby the CSB-content may be up to 10.sup.6 mg/l or more. This process comprises a putrefactive process which is induced in at least one decomposition tank at about 34.degree. C. by circulating normal sewage sludge, whereby upon start-up of the putrefactive process, a change to chemical process waste waters is carried out without adding communal sewage sludge. Subsequently, the sludge is withdrawn from the decomposition tank, flocculated, and returned to the external circulation for circulating the putrefactive sludge in the decomposition tank.

Abstract: The present invention provides an improved biological sludge dewatering process. The process comprises the steps of: (a) heating biological sludge to a temperature of about 90.degree. to about 150.degree. C. which corresponds to a pressure of about 0 to about 55 psig and retaining the biological sludge at that temperature for less than about 15 minutes; (b) centrifuging the heated biological sludge to isolate the solids of the heated biological sludge from the liquid of the heated biological sludge; (c) chemically conditioning the isolated solids; and (d) dewatering the conditioned solids to produce a high solids biological sludge. The present process is used for dewatering any biological sludge to produce a high solids cake. The resulting high solids cake may be used as landfill, incinerated, or used as fertilizer by spreading on land and plowing said fertilizer into the soil.

Abstract: A process for treating pretroleum refinery sludge to produce a coke-like residue product wherein an oily petroleum refinery sludge containing organic solid material boiling above 1000.degree. F. and water is heated to a temperature above the boiling point of water and below the thermal cracking temperature of hydrocarbons and water in the sludge forms steam used to steam strip any light hydrocarbons from the organic solid material which is recovered as a solid coke-like residue product.

Abstract: The present invention is in a process for the treatment of clarification sludge, wherein a sludge is treated with a per acid containing up to 3 carbon atoms and subsequently allowed to digest in a septic plant.

Abstract: In the method for concentrating/dehydrating sewage sludge including activated sludge with the aid of organic polyelectrolytes and/or inorganic flocculators the activated sludge portion is produced in an aerated biologic clearing step in presence of--based on the amount of liquid flowing into the clearing step--5 to 0.01 parts by weight per million parts by weight of at least one compound selected from the group consisting of folic acid, dihydrofolic acid and at least an ammonium alkali metal salt, alkaline earth metal salt and alkanolammonium salt thereof.

Abstract: A thickener well is provided in one end of a digester orbital ditch having a pair of channels and an elongated center partition spaced from a pair of ditch endwalls, the overall ditch forming a basin for digestion of wasted sludge. A curved endwall of the ditch provides a common curved top outer peripheral wall of the thickener well. The remainder of the well has a cylindrical configuration integral with the orbital ditch bottom and extending downwardly therefrom to a position below the horizontal plane of the ditch bottom. A sludge raking structure is positioned at the bottom of the well for periodically raking settled sludge into a sludge outlet at the bottom of the well. A surface aerator is provided between and spaced from the other ditch endwall and a juxtaposed end of the partition or other aeration apparatus mounted in a channel(s) to aerate and propel a liquid-solids sludge mixture wasted from a secondary treatment apparatus and fed into the orbital ditch.

Abstract: An apparatus for sludge thickening including a sludge thickener allowing suspended solids of sludge supplied thereto to settle by their own weight while being thickened. The sludge supplied to the sludge thickener is subjected to aeration for a predetermined period of time in a sludge aerator. Aeration of the sludge strips the anaerobic gas, which is attached to the suspended solids in the form of bubbles or dissolved in the sludge, to atmosphere. By aeration of the sludge before being fed to the sludge thickener, floating of the thickened sludge in the thickener can be avoided.

Abstract: Novel process for the removal of hydrophobic oil from solid particulates in oily sludge waste which includes waste material from the oil refineries, drilling fluids or muds, brines, and other chemical wastes which have solid particulates contaminated with oil. The process involves separation of different components of the sludge on the basis of their size, density and physico-chemical differentials. Coarse particulates are removed with the use of screening systems such as sieve bends or vibro-sieves. Oil is removed from these coarse particulates with water rinsing. The separation of the sludge into high and low density fractions may be achieved by gravity separation processes or hydrocyclones. Froth flotation is used to separate hydrophobic materials from hydrophilic materials in the mixture.

Abstract: A process for treating waste material is disclosed wherein the initial steps are performed in the dry stage including the removal of dirt, metallic and glass materials, and separation of the dry materials and thereafter passing the materials through a horizontal rotary pulp separating mechanism which delivers to a pulper and to an anaerobic process chamber.

Abstract: This invention relates to a process for the combustion of aqueous sewage sludge comprising burning, in a fluidized bed furnace, an aqueous mixture of a sewage sludge and a TDI residue, said aqueous mixture having a total solids content of from 25 to 98% by weight of the aqueous mixture, wherein the TDI residue comprises 25 to 95% by weight of the total solids content.

Abstract: A method for dewatering a slurry of solid particles suspended in a liquid using a twin belt press dewatering system, comprising the following steps:feeding the slurry of solid particles into the dewatering system;feeding a cationic amine salt solution into the dewatering system at a point just prior to the mixing drum, the cationic amine salt being a latex copolymer of acrylamide and dimethylaminoethylmethacrylate sulfuric acid salt having a mole ratio in the range between about 30:70 to 70:30, preferably 53:47;mixing the cationic amine salt solution with the slurry of solid particles in the mixing drum; andfeeding the cationic amine salt solution/slurry mixture to the twin belt press, whereby the slurry of solid particles is dewatered. The cationic amine salt solution having a strength of less than 1% and a polymer concentration of about 35%.

Abstract: Process and apparatus for thickening or dewatering treated sludge in one or more thickening tanks includes the addition of nitrate ions to treated sludge as a mechanism for generating microscopic bubbles of nitrogen gas which adhere to, or are trapped by, sludge floc particles, causing a reduction in density of the particles which, in turn, causes the particles to float to the top of the thickening tank. The process separates the sludge into an upper thickened layer and a lower free water, or subnate, layer. Subnate is removed from the tank through a plurality of outlets arranged at different depths within the tank. The subnate outlets are shut off sequentially, from the highest to the lowest, as the level in the tank drops. Thereafer, the thickened sludge is removed from the bottom of the tank and pumped to a sludge disposal location. A portion of the thickened sludge may be recirculated to insure flow uniformity.

Abstract: Sewage is separated in an offshore facility into effluent and sludge. The effluent is used to provide nutrients to a seaweed farm. The sludge is transferred to flexible storage balloons and digested to produce methane which is recovered and dried. The digested sludge is then dried for fuel use.

Abstract: The invention relates to a method for producing a product from which compost can be suitably produced and which contains sludge obtained from a sewage purification process, in which method the sludge is mixed in a fluid state with a finely-divided carbon-carrier selected from the group sawdust, peat and bark, and with polyelectrolyte, and is then mechanically dewatered to a dry substance content of at least about 28 percent by weight.

Abstract: A method for improving the waste treatment of industrial bakery plant effluent by taking clarified effluent which has been subjected to pH changes to form sludge in a primary clarifier, removing said effluent from the initial sludge in the clarifier, and circulating it after sludge separation therefrom into a series of three underground tanks where a solution of activated anaerobic bacteria is metered. The residence time, for the effluent and bacteria in said tanks is 48 to 72 hours at a temperature of 28.degree. C. to 48.degree. C. Thereafter, the treated effluent is recirculated once again to a lower clarifier which feeds any sludge formed into a sludge concentration tank, while the aqueous effluent remaining is further processed in a sand filter, an ozonator, and a reverse osmosis unit to achieve a BOD level of below 150 (mg/l) and a COD level of below 80 (mg/l).

Abstract: A method for the draining of sludges utilizing a filter aid composed of a mixture of porous organic materials capable of absorbing large amounts of liquid to absorb the sludge particles and a ballast liquid containing particles larger than the sludge particles is disclosed. The filtering aid prevents the redissolving of the sludge particles normally observed in chemical flocculation and chemical contamination of the agent.

Abstract: The invention relates to a process for thickening digested sludge, comprising the steps of providing digested sludge to be thickened, and then passing a gas, preferably air, through the digested sludge at an intensity in the range of above 0.1 to 5 gas to 1 sludge, on a volume basis, per hour. Sludge can be thickened to greater than 5% solids in ten days, an improvement of nearly 10 times that of traditional practice, as shown respectively by plots B and A.

Abstract: According to an embodiment thereof, the method comprises using a pair of reaction vessels, sequentially, to treat the sludge. Both vessels are pressurized, and the first thereof has an aerator for aerating the sludge, and receives sulfuric acid and chlorine thereinto through a port. A dewatering device is provided upstream of the first vessel, and the outlet of the first vessel is coupled to an inlet of the second vessel through another dewatering device. The second vessel defines a final-treatment chamber in which the sludge is exposed to ozone, air and lime. The treatment method, then, comprises the steps namely: introducing the sludge into the first vessel and oxidizing and depressing the pH of the sludge so introduced, and recycling the sludge in the first vessel over a given period of time. Thereafter the sludge is dewatered and conducted to the second vessel wherein it is exposed to air, ozone and lime, as aforesaid, and discharged after a like period of time.

Abstract: A system for utilizing and disposing of sludge and other wastes employs an artificially created perched bed and a subsurface injector system that applies such wastes in a liquid or semi-liquid state to an aerobic portion of the bed. The solids from the waste mixture are suspended in the bed while the liquids percolate through the bed to an underdrain system for collection, monitoring, further treatment, ultimate reuse, or direct discharge. The system provides closed loop disposal of the waste stream in a completely controlled environment without impact to the local environmental system. The bed's selected media can be changed into a beneficial by-product--top soil--through the addition of the waste material. Subsurface injection may be accomplished by moving an injector sweep either by a vehicle supported on the artificial bed or by a movable superstructure. Repeated applications of sludge or waste may be made to the bed without plugging due to the disruptive action of the injector sweep on the bed material.

Abstract: A method for biologically purifiying waste water which produces substantially no excess waste sludge is provided. In this method, a waste water containing biodegradable substances is treated in a biological fixed film type reactor and aqueous water sludge discharged from the reactor is aerobically digested after being separated from the biologically treated waste water. The digested aqueous sludge is returned to the reactor or the upstream thereof. This method can be advantageously combined with any installed activated sludge type water purification process, to thereby substantially eliminate the production of excess waste sludge from the water purification system.

Abstract: The invention relates to a method of producing an aqueous solution rich in phosphorous and recovering metal compounds in the purification of sewage-water or raw-water, in a plant which includes at least one chemical treatment stage in which an iron compound is supplied to the water to precipitate phosphorous present therein. The method is characterized in that the sludge from the chemical treatment stage is treated with hydrogen sulphide under anaerobic conditions, phosphorous compounds being dissolved from the sludge and metal sulphide being formed. The metal sulphides are dissolved to form metal salt solutions, of which at least the iron salt solution is separated and recycled to the chemical treatment stage. It is also possible prior to separating the iron salt solutions to recycle the metal salt solutions one or more times. The dissolved phosphorous can be removed in the form of an aqueous solution and treated in accordance with the so-called Donnert-process, to form calcium phosphate.

Abstract: A method for composting decaying material by first treating the material to produce a decayable carbon/nitrogen ratio and continuously and countercurrently aerating the decaying material in a first step to produce a biologically active material and then introducing the biologically active material to a second step wherein it is discontinuously aerated at controlled intervals. The process produces a hygienically unobjectionable humus material in a continuous and industrially efficient manner.

Abstract: Method for making of solid fertilizer by separation of liquid manure into a solid and a liquid phase by means of a separating vessel, wherein the charged liquid manure at first is divided into a solid layer and into a liquid phase and from where the liquid phase is fed into a collector vessel, and whereby the solid phase is separated. The duration time of the liquid manure in its resting stage is delayed until the layer formed by the solid phase is separated on the top of the vessel and then the discharge of the liquid phase is carried out through closeable openings.

Abstract: A process and an apparatus for mechanically dewatering municipal sewage sludge or peat. The undewatered feed material is passed into the first end of a cylindrical porous wall and pressurized within the cylindrical wall by a rotating screw conveyor, which also transports the solids toward the second end of the cylindrical wall. The screw conveyor comprises a central shaft which has at least two built-up sections of gradually increasing diameter providing a compression ratio of 2.5:1.0. The flight depth of the screw conveyor increases by a factor greater than 2.0 after each built-up section. The distance between the edge of the screw conveyor blade and the inner surface of the cylindrical wall and the structure of the openings in the wall have specific dimensional limitations. Fibrous additives may be used to aid in dewatering peat and secondary sludges.

Abstract: A process for achieving the partial dewatering of an organic sludge by isolating a batch of the sludge, acid adjusting its pH into a range from 3 to 5, and adding an oxidizing reagent in the presence of the acid in sufficient quantity so that within one-half hour the cellular structure of the sludge has been partially broken down and enough occluded water released therefrom to increase the pH by at least one, while at the same time changing the color of the sludge to a light tan and deodorizing it and killing the pathogens therein, the sludge and other solids settling down below the supernatant liquid with a clear line of demarcation therebetween.

Abstract: Anaerobic digestion of organic material, particularly biological sludge, such as sewage sludge, is carried out in a closed system having a first digestion tank and a second concentration and partial digestion tank. The concentrated and partially digested sludge is fed to the first tank where it is maintained under vacuum such that an active zone of organic material undergoing digestion is detained therein for a long period of time. The digested sludge is withdrawn against the vacuum and has approximately 80 to 90% of the organic solids therein mineralized; thus simplifying dewatering and ultimate disposal of the sludge. Pathogens including viruses are also removed from the digested sludge. Denitrification takes place in the vacuum digester tank and gas consisting essentially of nitrogen is removed. Return sludge from the vacuum digester and influent sludge is fed into the second or concentrator tank to facilitate reseeding with anaerobic organisms.

Abstract: A method is disclosed for the chemical detoxification of anaerobically digested organic sludge containing toxic heavy metals in insoluble form. A quantity of the sludge is transferred from a conventional anaerobic digester to an insulated reactor vessel where the sludge is mixed and aerated at a rate sufficient to raise the oxidation reduction potential of the sludge to above +300 mv. and to maintain this condition for a period of 6-12 hours during which the heavy metals are converted to their desired oxidation state. The sludge is then acidified under controlled conditions to pH 1.0-3.0 for a period of 6-12 hours to solubilize the heavy metals. Conventional dewatering techniques are used to separate the detoxified, acidic sludge and the acidic, heavy-metal-containing water. The sludge may be neutralized for safe land application, and the metals can be recovered from the water using existing conventional techniques.

Abstract: The manure, which has been previously finely ground, is diluted (3) so as to form a liquid mixture containing not more than 4% of solid material. This mixture is fed into a bioreactor (6) of which the gas is used to feed the burner (11) of a dryer (10) in which the manure particles are dried. Before and after passage of the mixture into the bioreactor, filaments and fibres are separated (4,9). At least part of the liquid separated in the second separator (9) is recycled (13) in the initial liquid mixture. The energy of the water vapor from the drying is used to activate the bioreactor (16). The residual liquid not recycled is subjected to a nitrifying/de-nitrifying treatment (15). The residual mud may be collected (23) and mixed with the dried product, as well as the fibres and filaments eliminated. The mud, the filaments and the fibres, rich in proteins, may be used directly as foodstuff for cattle. The other residual product are appropriate for use as fertilizers.

Abstract: A method is described for converting substantially untreated organic sludge into useful substances. The sludge may include primary sludge, a mixture of primary and secondary sludges from municipal wastewater treatment facilities, slurries of agricultural manure, and other organic wastes. The sludge is mechanically comminuted to reduce the size of organic solids, the sludge is then further mechanically disintegrated and thereafter it is subjected to enzyme hydrolysis to produce a biologically stable colloidal slurry with improved biochemical potential reactivity. Typically, the hydrolysis step is followed by a further cell/particle disintegration step and a secondary hydrolysis step. If necessary, heavy metals are removed from the suspension in a chelating step which are recovered as a recyclable concentrate. The suspension can be used as a liquid fertilizer or it can be dewatered. If used as a liquid fertilizer the suspension can be inoculated with microalgae to enrich the fertilizer with nitrogen.

Abstract: Disclosed is a method for removing inorganic acid-forming constituents from a gas stream contaminated therewith (e.g. high sulfur coal effluent). Such removal is accomplished by passing the gas stream through an active composting biodegradable organic waste held under thermophilic bacteria-phase digestion conditions. Also disclosed is a comprehensive composting treatment site which desirably employs a windrowing composting technique and is suitably adapted to be operated with the gas stream scrubbing process disclosed herein.