Abstract: A two-step process for microbiological purification of contaminated water, comprising a first step using anaerobic conditions in a reactor having a stationary bed and a biofilm fixed thereon followed by conventional microbiological purification, characterized in that in said first step the water is supplied at the upper end of the reactor and is brought to trickle over the fixed biofilm without drenching the bed and while maintaining a continuous gasphase within the bed.

Abstract: A method of controlling biofouling in a aqueous systems comprising introducing into the system a biocidally effective amount of a water soluble perhalide of the formula: ##STR1## where R.sub.1 and R.sub.2 are hydrogen, hydroxyethyl, alkyl, cyclic alkyl, (alpha, omega)-alkyl, alkyl ether, polyether, heterocyclic ring-substituted alkyl, and halogenated alkyl; n is 2 to 6: X is chlorine, bromine or iodine; and only one of R.sub.1 and R.sub.2 may be hydrogen.

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: A water ozonization system equipped with a filter in that water can be treated with ozone through the steps of installing a diverging pipe therein to allow part of raw water to diverge from the discharge side of a raw water pump, the diverging pipe being fitted with an ejector; injecting and introducing the ozone obtained from an ozonizer into the ejector via its suction port in order to form ozonous water; returning the ozonized water via a diverging pipe to the suction side of the raw water pump; and supplying the ozonous water and unreacted ozonizing gas to the whole quantity of raw water within the limit to which the raw water pump produces no cavitation so as to increase ozone absorption efficiency with the agitation of pump impellers for accelerating ozonization and the reaction of the unreacted ozonizing gas in the raw water pump on the whole quantity of the raw water by ozonizing means.

Abstract: A method and apparatus for separating liquid for material of differing permativity is disclosed. The method involves the application of an AC voltage to a material to create an a non-uniform electric field of the same frequency as the applied AC voltage which decreases in strength the further the radial distance from the point of application to induce flow of the liquid in the material. Collection means are located in the path of induced flow to collect the liquid. The apparatus of the invention consists of a means of generating an AC voltage, a terminal in contact with material and connected to the means of generating the voltage so as to receive the material and impart a non-uniform electric field to the material. Means for collecting the liquid that collects at a region in which the liquid is concentrated is also provided.

Abstract: A process is disclosed for removing heavy metals, dissolved aluminum, sulfides and organic compounds from a caustic etch solution, thereby regenerating the etching power of the solution or facilitating its disposal into the environment. The process consists of forming a first filtrate from which heavy metals present in the solution have been removed, and a second filtrate obtained by precipitating and oxidizing residual chemicals remaining in the first filtrate. The latter is done over a selected pH and temperature range. The second filtrate is then either reclaimed back to the etching tank, or subjected to ozonization prior to disposing of it into the environment.

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: Wastewater is effectively disinfected while reducing both chlorine consumption and more particularly the levels of residual chlorine discharged from the wastewater treatment plant. The wastewater is first contacted with a sufficient amount of chlorine to satisfy the chlorine demand and to obtain as low a residual level of chlorine as possible. After the chlorine demand has been satisfied, the wastewater is disinfected with an effective amount of 2,2-dibromo-3-nitrilopropionamide.

Abstract: There is disclosed an activated sludge wastewater treatment process which comprises aerating a mixed liquor comprising phosphate-containing influent wastewater and activated sludge in an aeration or high-purity oxygen zone to reduce the BOD/COD content of the wastewater and to cause the microorganisms present to take up phosphate. A phosphate-enriched sludge in which the phosphorus is present primarily in the sludge solids is separated from the mixed liquor to provide a substantially phosphate-free effluent. At least a portion of said phosphate-enriched sludge is passed to a phosphate pre-stripping zone, either in a separate tank or within the phosphate stripper tank itself, where BOD/COD-containing water, or feedwater, containing at least 50 mg/L of BOD, is added to poise the sludge organisms to begin enhanced rapid release of dissolved phosphate by pre-stripping it from the sludge or poising the sludge for rapid, enhanced release of phosphate. Then, the sludge is passed to a phosphate stripping zone.

Abstract: A method for waste treating metal containing solutions comprising decomposing the metal from the solution in the substantial absence of air and separating the decomposed (precipitated) metal from the solution.

Abstract: An improved oxidation and photooxidation process for treating water containing an oxidizable contaminant. In one embodiment, the organic compound does not have an electron donating aromatic group. A stochiometric excess amount of a calcium salt is added to precipitate carbonate and bicarbonate ions contained in the water as calcium carbonate. The calcium carbonate is removed from the water and the filtered water is then subjected to an oxidation process. In another embodiment, the organic compound does have an electron donating aromatic group. Carbonate and/or bicarbonate is added so that the water has a stochiometric excess amount of carbonate and bicarbonate. The water is then subjected to an oxidation process.

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 wastewater treatment system in which biologically active particulate material mixed with wastewater is recirculated under turbulent conditions. The biomass is maintained at high concentration, and recirculation of the particles maintains the biological layer on the particles at a more active and efficient state would be the case without such recirculation. The system is particularly efficient, especially when the organic waste materials are slowly or relatively non-biodegradable, when the particulate material is adsorbtive (as, for example are particles of activated carbon) and the recirculation system includes an ultrafilter. When combined with a pretreatment of either alum or ferric chloride with lime, the system is particularly suited for efficient and effective treatment of dairy wastes.

Abstract: A method and composition for solidification or semicolidification of single or multi-phased waste including mixing the waste with a composition including having as its major component a cement, and, as lesser components, a fixative, an absorbant, and optionally an emulsifier. The composition of the invention is mixed with the waste and dried.

Abstract: A method of treating solid hazardous waste containing unacceptable levels of leachable metals such as lead and cadmium includes mixing the solid waste with lime and an agent selected from the group consisting of carbon dioxide and bicarbonate. After the solid waste and agent are mixed under conditions which support reaction between the agent and metals, the metals will be converted to nonleachable forms which are relatively stable under normal environmental conditions. If the solid waste material and agent are both dry when mixed, it may be beneficial to add water to facilitate the mixing of the solid waste and agent and the conversion of the metals into nonleachable forms.

Abstract: An improved anaerobic fermentation process and apparatus for converting an influent liquid containing suspended organic matter to effluent gas and liquid products are provided. The influent liquid is introduced into and maintained in an anaerobic fermentation reactor containing anaerobic microorganisms at a temperature and a first pressure and for a time sufficient to form a gas containing methane and to form a liquid containing dissolved gas and suspended bacterial cell mass particles. The liquid is introduced into and maintained in a flotation vessel at a temperature, at a second pressure and for a time whereby gas dissolved in the liquid is liberated forming solution gas bubbles which rise and cause the suspended bacterial cell mass particles to be floated to the surface of the liquid. The floated bacterial cell mass particles are withdrawn from the surface of the liquid and from the flotation zone and recycled to the fermentation zone.

Abstract: A process for treating wastewater to biologically remove phosphorous as well as lowering ammonia, TSS and BOD levels is provided. The process employs a plurality of basins which may be individually controlled to achieve anaerobic, anoxic or aerobic conditions. The basins are reconfigurable in that the flow of influent to a basin, transfer of mixed liquor between basins and effluent discharge from a basin can be varied to create a treatment cycle which has features of both continuous and batch processes while minimizing recycle rates and hydraulic level changes.

Abstract: This invention relates to a process and reactor system suitable for biological treatment of wastewaters or for other applications wherein effective and intimate contact between biological populations attached to a fixed surface and liquid born chemicals and gaseous atmospheres is required. The reactor includes a sealed housing generally having a plurality of independent-vertical chambers, each open at the top and bottom and each filled with high surface-area packing and disposed annularly around a central-vertical chamber. The central vertical chamber is also open at the top and bottom, but free of packing. The bottom of the central chamber is in communication with the bottom of each of the independent-annular columns by means of a bottom-freeboard chamber. The top of the central-vertical chamber is also in communication with the top of each independent-vertical chamber by means of a top-freeboard chamber created by setting the liquid level in the reactor at a position above the top of all vertical chambers.

Abstract: A method of attacking and removing microbial slime in slime covered surfaces and maintaining a slime-free surface as in exposed cooling tower surfaces and in waste water treatment and paper making. This method comprises utilizing an enzyme blend in 2 to 100 parts per million (ppm) of cellulase, alpha-amylase and protease. Such enzyme blends have been found specifically to digest microbial slime and reduce microbial attachment and biofilm. A specific combination of polysaccharide degrading enzymes is a ratio of 2 parts cellulase to 1 alpha-amylase to 1 protease utilized in 2-100 parts per million. Broadly, the alpha-amylase must be at least 1 and the protease may vary from 0.5 to 1 part.

Abstract: This invention relates to apparatus for treating sewage sludge in a hyperbaric vessel in which the sludge is oxygenated by injecting an oxygen-rich gas into the sewage sludge and then dispersing the mixture of sludge and oxygen-rich gas into the upper portion of a hyperbaric vessel for further interaction with an oxygen-rich atmosphere. The oxygen-rich gas is injected into the sewage sludge by delivering the gas to a combination gas and sludge mixing and dispersing assembly. The gas and sludge are mixed within a plurality of channels formed in the assembly before the mixture is dispersed from the channels.