Abstract: The present invention provides a process for the control of a biological rification stage of the aerobic activated sludge type, wherein at least one of the micro-organisms most frequently present in the activated sludge is continuously monitored with regard to the amount thereof in that, in a representative sample from the activated sludge and/or from the inlet of the activated sludge tank, this micro-organism is bound to fluorescence-labelled antibodies directed against the chosen micro-organism or this micro-organism is allowed to react with a fluorogenic substrate by means of a special metabolic ability, the amount of the thus fluorescence-labelled micro-organism is determined by flow cytometry and, at the same time, the total amount of the micro-organism present is determined by scattered light measurement and/or coloration of the DNA and, depending upon the measurement values thus obtained, the amount of at least one particular micro-organism and/or the growth conditions for this micro-organism is regula

Abstract: The present invention deals with wastewater treatment systems, and more particularly with trickling filter systems using distribution tubes or arms rotating about a central point above filter beds to distribute wastewater thereto. The present invention comprises an auxiliary or backup motor drive mechanism for a rotary wastewater distributor and includes a prime mover, preferably an electric motor, a transmission system, preferably a sprocket and chain drive, and a sensing system to turn the auxiliary drive system on when flow rates are too low to maintain the normal hydraulically driven rotation of the distributor. The auxiliary drive system further comprises protective mechanisms to turn the prime mover off whenever speeds afforded by the wastewater flow are adequate for proper distributor operation or whenever the auxiliary drive system is overloaded due to a failure of rotation of the distributor.

Abstract: A method for treatment of waste water by an activated sludge process wherein the aeration tank system is composed of three tanks: a first tank, a second tank and a third tank, in which sludge microorganisms adsorb the organic substances in the waste water to be treated and a part of them begin oxidation and decomposition of the substances in the first tank, the organic substances which are adsorbed by the sludge microorganisms are further decomposed by the microorganisms of the second tank, and the sludge microorganisms are activated in the third tank, is disclosed. The aeration amount to the respective tanks is controlled to fall within specified ratios. Further, the pH value in the aeration tank system is controlled to be slightly acidic, and the pH of the tanks increases in order from the first tank to the third tank. The process may also be carried out in a single tank using a three-step batchwise process, where the batches are subject to the aeration and pH requirements.

Abstract: A method and system for optimizing the operation of a trickling filter. Optimization is obtained by using a controlling device and a variable speed drive in combination. The drive motor rotates the distributor mechanism of the trickling filter in response to signals transmitted thereto by the controlling device. The signals received are either based on the influent flow rate or a pre-programmed system representing the above. In response to these signals, the speed of rotation of the distributor is continually varied to provide a SK value most conductive for (1) reducing the BOD and ammonia levels present in the wastewater influent, (2) removing excess bio-mass attached to the media used in the filter and (3) driving the organic food materials deeper into the bio-mass. SK values of between 5 to 100 mm/pass are used for normal operation and a SK of 100 to 1000 mm/pass for flushing during non-peak hours. An intermediate SK value is used to drive the organic feed deeper into the media.

Abstract: Lignocellulosic material such as agricultural residues, e.g. straw and bagasse, can be converted into products that can be easily transformed into feeds, fuels, and soil improver. The reactor described herein affords simple efficient transformation of lignocellulosics to acidic organic liquid, heat, and ligneous sludge residue in a typical use. The acidic organic liquid may be used as the main component in the production of SCP, the heat may be used subsequently for heating or drying, and the ligneous sludge, when dewatered, used as soil improver or as fuel.

Abstract: The present invention refers to a process for wastewater treatment, wherein the amount of soluble organic matter is reduced by means of addition of nitrate. A relief of the wastewater treatment plants is obtained by the fact that the agent is added as early as possible in the pipe line net. The addition of nitrate may be controlled by measurement of the redox potential.

Abstract: Improved process control is achieved in processes for which it is useful to control variable process conditions based upon on-line determinations of the concentration of weak acids and weak bases, or their soluble salts, in liquid streams of the processes. For example, amine system energy savings and waste treatment system control improvements are taught.

Abstract: This invention describes a biological inhibition/toxicity detector, which provides an early warning of a process upset due to possible inhibition/toxicity problems in biological reactors treating municipal and/or industrial wastewaters. The detector basically comprises separate means for providing two liquids in communication with a mixing tank, a spiral plug-flow reactor, two dissolved oxygen (DO) probes, a DO analyzer, a computer, and a chart recorder. Two pumps can continuously pump portions of wastewater to be tested and acclimated active biomass (mixed liquor) from a biological reactor into the mixing tank. The wastewater and biomass are mixed and oxygenated in the tank, and then continuously fed to the plug-flow reactor. The DO concentrations at the front and back ends of the plug-flow reactor are measured separately by the two DO probes.

Abstract: A waste water treatment process wherein an iron contactor or iron contact are immersed in a treatment tank, into which waste water flows. In the treatment tank sulfate reducing bacteria are made to coexist with activated sludge or biofilters, wherein a velocity of flow of agitating stream on the outer surfaces of said iron contactor or contactors is set at 10 to 20 cm/sec, under an aerobic treatment. Iron ions are made to elute from said iron contactor or contactors by utilizing electrochemical iron corrosion through the agency of oxygen concentration cells on the outer surfaces of said iron contactor or contactors on conditions that dissolved oxygen concentration in the treatment tank is 1 to 3.2 mg/l and the oxidation-reduction potential is -200 to -400 millivolts (mV). Under an anaerobic treatment, iron ions are made to elute by utilziing microorganism-corrosion on the outer surfaces of said iron contactor or contactors on condition that dissolved oxygen concentration in the treatment tank is 0 mg/l.

Abstract: Aerobic wastewater treatment processes are controlled utilizing alkalinity measurements. A base line of alkalinity is determined by measuring the alkalinity profile of the influent to the aerobic wastewater treatment process. The alkalinity of the wastewater is sensed at a number of different points in the aerobic wastewater treatment process, such as at a clarifier effluent and sludge exit, aeration zone, and aerobic digester effluent. When the sensed alkalinity at any given point is above a predetermined amount over base line alkalinity, the air supply is increased and/or the concentration of microbes and food is reduced (as by increasing the sludge withdrawal rate from a clarifier) until the sensed alkaline level is stabilized. When the sensed alkalinity is below a predetermined amount under base line, the air supply is decreased and/or the concentration of feed and microbes increased (as by reducing or terminating sludge withdrawal from a clarifier) until the sensed alkalinity level is stabilized.

Abstract: Solutions containing pesticide wastes from greenhouses, for example, are decontaminated in a system including a soil bed reactor. Waste water from the greenhouse goes to a sample tank from which samples are withdrawn for assay of toxicity. Water from the sample tank goes to a holding tank, or to a downstream subsystem if toxicity level is low. Water in the holding tank is aerated to promote degradation of toxic materials. Water from the holding tank is applied near the upper surface of a layer of soil in the soil bed reactor. Air from the sample tank and holding tank, and intermittently, air containing pesticides from the greenhouse, is also passed through the layer of soil in the soil bed reactor. Microbial action in the soil degrades toxic materials in both the gaseous and liquid streams. Water from the soil bed reactor may then be discharged to a pond populated by plant and animal species which promote further degradation of any remaining toxic materials before the water is discharged from the system.

Abstract: A method for biologically removing approximately seventy-five percent of the phosphate contaminants from wastewater comprises controlling the aerator to a single activated sludge tank according to the turbidity of the water and the effluent requirements. Oxic, anoxic, and anaerobic reactions occur sequentially over the entire volume of the single reactor. Greater phosphate removal requires a simultaneous chemical precipitation.

Abstract: This invention comprises the steps of (1) acid phase anaerobic digestion of biomass to produce volatile acids and a stabilized sludge, (2) use of the volatile acids as the carbon source and electron donor for biological sulfate reduction for removal of acidity, metals and sulfate from acid mine drainage, and to produce acetate, (3) use of the acetate solution as feed for methane phase anaerobic digestion to produce methane and to reduce the organic content of the effluent of the process, (4) and use of the methane to satisfy the energy requirements of the process. Key to the process is the use of kinetic control (i.e., a relatively short mean cell residence time) to ensure partial oxidation of higher molecular weight volatile acids (e.g., propionic, butyric, valeric) and production of acetate during the sulfate reduction step.

Abstract: Wastewater containing impurities refractory to secondary treatment is first introducted into an aerobic biological treatment stage operating with an oxygen-enriched stream and subsequently into a precipitation stage where the biologically treated wastewater is combined with Ca(OH).sub.2 to precipitate Ca(OH).sub.2 CaCO.sub.3 sludge which adsorbs or occludes impurities. The clear liquid, separated from the resultant sludge, is passed to a second precipitation stage where it reacts with a CO.sub.2 and oxygen-containing waste gas at least in part from the aerobic biological treatment stage, thereby forming additional CaCO.sub.3. Waste gas withdrawn from the second precipitation stage, being enriched in oxygen is recycled to the aerobic biological treatment stage.

Abstract: A biological contactor (8) comprises a granular bed including a layer (17) based on activated carbon the material of which satisfies the following conditions:density between 0.18 and 0.32 g/cm.sup.3,carbon tetrachloride adsorbing power between 60% and 120% by weight,carbon tetrachloride retention less than 25% by weight of the carbon tetrachloride adsorbed mass,methylene blue: between 5 and 30 ml,particle size: between 0.5 and 1.5 mm effective size with a coefficient of uniformity less than 2.A washing cycle (21, 24) (air only; air plus water; water only) of the contactor is triggered (38) when a parameter (36, 37) representative of the population of algae in said layer reaches a predetermined set point threshold.

Abstract: A process strategy for the treatment of wastewater in a sequencing batch reactor wherein wastewater in quantities above a preselected minimum amount is proportionally aerated so as to reduce energy usage and operating costs.

Abstract: Aerobic purification of waste water with intermittent batchwise supply of waste water to the activated sludge tank from which the treated waste water drains continuously is disclosed, in which the nitrate content in the waste water is simultaneously reduced by throttling the aeration of the activated sludge tank, starting with the admission of the waste water to the tank, to values equivalent to less than or equal to 0.5 mg/l dissolved oxygen. In particular, aeration may be off until such time as the nitrate content in the tank has dropped below 5 mg/l, in particular below 1 mg/l. In the case of urban waste waters a cycle time of about 1 hour is expediently employed under these circumstances and the aeration is shut off for about 5 minutes, starting from the rapid admission of the waste water charge. Preferably, inlet charges are less than or equal to 30%, in particular between about 5% and 20%, of the tank capacity.

Abstract: Aerobic wastewater treatment processes are controlled utilizing alkalinity measurements. A base line of alkalinity is determined by measuring the alkalinity profile of the influent to the aerobic wastewater treatment process. The alkalinity of the wastewater is sensed at a number of different points in the aerobic wastewater treatment process, such as at a clarifier effluent and sludge exit, aeration zone, and aerobic digester effluent. When the sensed alkalinity at any given point is above a predetermined amount over base line alkalinity, the air supply is increased and/or the concentration of microbes and food is reduced (as by increasing the sludge withdrawal rate from a clarifier) until the sensed alkaline level is stablized. When the sensed alkalinity is below a predetermined amount under base line, the air supply is decreased and/or the concentration of feed and microbes increased (as by reducing or terminating sludge withdrawal from a clarifier) until the sensed alkalinity level is stabilized.

Abstract: A method and system for removing pollutants dissolved in the aqueous discharge of a plant, such as a power plant, from a body of water having known hydraulogy and physicochemical characteristics, the method comprising (a) modifying the hydraulic system of the body of water including use of physical barriers to define a zone in a portion of the body of water which zone includes the discharge point and where the water has a range of physicochemical characteristics; (b) selecting a large and preferably filamentous, planktonically growing strain of algae adapted to absorb the particular pollutants and genetically dominating algae at the physicochemical characteristics of the zone; (c) establishing a colony of the selected algal strain in the zone; (d) harvesting a portion of the colony; and (e) reinnoculating the zone near the discharge point with a fraction of the harvested portion. The fraction used for reinnoculation can be adjusted to balance the rate of pollutant removal to the rate of pollutant discharge.

Abstract: In a method of monitoring and/or controlling a biologically catalyzed reaction, a trace gas which either is, or equilibrates with a metabolic intermediate is identified, and the concentration of the trace gas evolving from the reaction is measured. The measured concentration of trace gas is employed to evaluate the metabolic status of the reaction by a deterministic relationshhip, e.g. an empirical relationship or thermodynamic model. The deterministic relationship may involve other gaseous parameters of the reaction. Preferably, the measured concentration of the trace gas is converted via the deterministic relationship into an estimate of the concentration of a different chemical component of interest for a particular application of the reaction. Carbon monoxide has been found to be a suitable trace gas for purposes of monitoring the metabolic state of the anaerobic digestion process.

Abstract: A process for the disinfection and aerobic stabilization of concentrated sewage sludge in several steps, using one or more heat-insulated containers, preferably with stirring, with the addition of an oxygen-containing gas, described wherein(a) the sludge coming in, having been concentrated to at least 2% of dry matter, is caused to reach the thermophilic temperature range of >50.degree. C., with pre-heating if required, and then solely by an aerobic degradation without supplying external heat within from 2 to 4 days,(b) the sludge is disinfected by further aerobic degradation without supplying external heat at about 50.degree. C. to 55.degree. C. for at least 20 hours or at >55.degree. C. for at least 10 hours, and(c) the sludge is stabilized to become mesophilic by way of actively cooling it down to about 25.degree. C. to 45.degree. C. and a further aerobic degradation within about 2 to 8 days, and preferably within from 3 to 5 days.

Abstract: A method for anaerobic biological waste treatment in multiple stages wherein a relatively high strength wastewater is introduced into a first biological reactor to produce an effluent of reduced strength, the effluent is passed into a second biological reactor for reaction therein, passage of the effluent into the second biological reactor is continued until the biological solids in the second reactor enter into a negative growth phase and become relatively stable, whereupon the flow of waste through the reactors is reversed by terminating introduction of the waste into the first reactor and passing the same into the second reactor to cause microorganisms in the second reactor to enter into a positive growth phase and the solids in the first reactor to enter into a negative growth phase.

Abstract: In a process and apparatus for the biological purification of water by means of a closed percolating filter operated with pure oxygen and/or air, and an upward-flow filter disposed downstream of the percolating filter, with flotation filter material therein, saturation of the gas cushion predominantly containing oxygen in the percolating filter is controlled by selection of the operating pressure in such a fashion that the oxygen supply corresponds to the biochemical oxygen demand of the water on the one hand, while on the other hand a residual oxygen content dissolved in the water permits continuation with a biological fine purification operation in the upward-flow filter. The apparatus comprises a first chamber with the percolating filter, the water flowing downwardly therethrough, and a second chamber with filter material through which the water flows upwardly.

Abstract: The filter bed containing aquatic plants planted therein is provided with a lengthwise and/or transverse drainage arrangement containing a predetermined number of drain pipes. Particularly during the growth phase of the aquatic plants, the drainage arrangement constitutes a by-pass flow path by-passing the aquatic plant-containing filter bed. The throughflow through such by-pass flow path is controlled as a function of the operating conditions using adjustable control devices. Furthermore and in order to also control the hydromorphous conditions of the aquatic plant-containing filter bed, outfeed level control devices are provided for controlling the hydraulic gradient along substantially the entire aquatic plant-containing filter bed as a function of its operating conditions. The throughflow through the aquatic plant-containing filter bed thus can be controlled for achieving optimum purification of the inflowing liquid under substantially all occurring operating conditions.

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: A method of treating wastewater using an aeration tank of the type having an interior divided into at least a first chamber and a last chamber with each of the chambers having a lower portion and an upper portion and having liquid passageways in the lower portions of each of the chambers and gas passageways in the upper portions of each of the chambers for allowing liquid and gas to pass sequentially through each of the chambers from the first chamber to the last chamber, having an effluent outlet associated with the last chamber of the aeration tank for allowing treated water to exit the aeration tank; and having agitator means to enhance oxygen transfer from the upper portion to the lower portion of the aeration tank.

Abstract: A system for the environmentally-safe, unified treatment of a wastewater effluent is disclosed in which there is provided:a primary treatment component comprising at least one means for the removal of solids,a secondary treatment component comprising at least one filtration field adapted for the secondary and advanced treatment of a wastewater effluent, and means to capture and convey effluent;an advanced treatment component adapted to provide further advanced treatment of a wastewater effluent comprisingat least one effluent accumulation means;at least one dosate storage and dosing means associated with each such effluent accumulation means; andat least one holding means capable of holding the dosed effluent in an anoxic condition;said advanced treatment component being adapted to accumulate, dose and hold the effluent for treatment in an anoxic condition; anda polishing component comprising at least one infiltration field to discharge effluent.

Abstract: A method for the treatment of wastewater wherein the turbidity level of the wastewater is monitored to control the operation of the aerating units, while simultaneously, the oxygen concentration in the aerating tank is monitored to control the staging of the aaerating units between the maximum and minimum turbidity levels.

Abstract: A process for purifying waste water resulting from the manufacture of chemo- and/or thermomechanical pulp, which comprises subjecting the waste water to at least the following sequence of steps:sedimentation of coarser constituents (4);cooling (6);detoxification (7);anaerobic hydrolysis and preacidification (10) with addition of nutrient salts and readjustment of the redox potential;production of methane in a methane reactor (11);aerobic purification and separation of biologic sludge (12; 13), which is at least partly recycled to the detoxification step (7), in which process aerobic sludge is separated prior to the anaerobic hydrolysis step (10).

Abstract: A method and apparatus for an anaerobic process to reduce caustic requirements and to facilitate dissolution of organic acid having limited solubility by combining effluent from an anaerobic reactor having dissolved carbon dioxide with fresh feed containing the organic acid and stripping the carbon dioxide from the mixture to raise the pH.

Abstract: The present invention relates to a method and equipment for carrying out the degradation of various organic products or waste in an anaerobic medium. The equipment comprises a plurality of ducts for reinjecting biogas into a fermentation vat sidewise spaced from each other and disposed at least in the major part of the vat, the duct being fed with biogas individually or in groups through independent valves so as to subdivide the fermentation vat into sectors independently fed with biogas. Preferably, a container is provided for storing biogas under pressure. These features lead to a simplification of the equipment and a decrease in the manufacturing costs.

Abstract: A process is disclosed to improve the efficiency of nitrification in activated sludge systems. Supplemental ammonium nitrogen in the form of anhydrous ammonia or an aqueous solution of ammonia is added to the nitrification zone preferably during periods of low flow and low loadings of oxidizable nitrogenous compounds. The ammonium nitrogen addition is controlled by monitoring the ammonium nitrogen concentration of the activated sludge mixed liquor exiting the nitrification zone. The supplemental ammonium nitrogen causes an increase in the population of the nitrifying bacteria which results in an increased capacity for nitrification. The increased efficiency obtained will result in increased reliability of nitrification and lower effluent nitrogen concentrations.

Abstract: The present invention is concerned with an intermittent aeration type biological treatment process and system, wherein waste water is caused to flow into an aeration tank, and aeration is repeatedly stopped and started in the aeration tank to treat the waste water. Concentration values of dissolved oxygen during aeration of the waste water in the aeration tank are continuously measured by a dissolved oxygen concentration measuring device provided in the aeration tank. Deficient values of dissolved oxygen and dissolved oxygen variation values at predetermined time intervals are calculated from the values thus measured. The deficient values and variation values are integrated and processed by an oxygen requirement value calculating-integrating operation unit to calculate an oxygen requirement value for the activated sludge in the current aeration step.

Abstract: A method for treating waste water from a catalytic petroleum cracking unit is disclosed. The method includes receiving step, aeration step, settling step, and a discharging step. In the receiving step waste water from which hydrogen sulfide and ammonium have been stripped out is introduced into a biological treatment tank. In the aeration step, the waste water in the tank is subjected to aeration for a predetermined period of time. In the settling step, activated sludge within the biological treatment tank is settled for a predetermined period of time. And in the discharging step, the supernatant is discharged from the tank subsequent to the settling step.The total duration of the aeration step performed daily is set to no longer than 12 hours and the aeration step is performed intermittently. If these conditions are met, yeasts which form pseudohyphae will grow actively enough to facilitate settling and separation of activated sludge.

Abstract: In the particular embodiments of the waste water treatment system described in the specification, a waste water treatment basin has spaced-apart, moving aerator chains extending across the basin in a direction transverse to the flow of waste water through the basin. When an aerator chain is provided with air, bottom aerators suspended from the chain adjacent to the bottom of the basin move with respect to the basin to mix sludge collected on the basin with the waste water and to supply air to the waste water. A control system supplies air selectively to the aerator chains to provide zones of full aeration and intermediate zones with little or no aeration and the selection of the aerator chains is changed periodically in a progressive manner along the basin so that the zones move progressively through the basin.

Abstract: A process for automatically treating a drain system to prevent or at least minimize clogging problems particularly in grease traps of the type provided in restaurants and other food preparation establishments. The process employs an apparatus which includes a valve for directing fresh water into the grease trap for pretreating the trap in preparation for the injection of bioactive liquid cultures by the pump. The liquid cultures liquify and digest contaminants in the grease trap which are flushed therefrom by fresh water. The apparatus is controlled by a system which cyclically operates the apparatus in accordance with a preferred operational sequence and at adjustably variable time periods.

Abstract: Waste water purification employing the activated sludge process with batch-wise waste water feed to the aeration tank. There is continuous aeration and water discharge from the tank. The process has a fixed dosing cycle based on historical values for the curve of the bacterial activity with the batch-wise waste water feed or a function of indicator values for this activity, specifically as a function of the oxygen concentration in the tank through an appropriate control, which briefly opens the waste water feed when, for example, an oxygen electrode indicates that an adjustable limit value has been exceeded. By means of such an oxygen electrode, an alarm signal can simultaneously be tripped if the high oxygen consumption expected after the admission of the waste water does not occur. The process is specifically useful for the treatment of waste waters which tend to form too much bulking sludge.

Abstract: A method and apparatus for determining the oxygen uptake rate of bacteria in a body of liquid incorporates withdrawing a sample of the liquid into a chamber where a dissolved oxygen probe is located, the probe outputting a signal which is a function of the amount of dissolved oxygen in the sample. The sample is aerated, and a computer is used to sample the signal at regular intervals to produce a series of time-separated values corresponding to the sampled signals, the values representing the dissolved oxygen in the sample at the timed intervals. Repeated samples can be taken, so that the O.U.R. can be monitored on a continuing basis. The O.U.R. information can be used to control the rate of aeration in a tank, or to control the rate of recycling of activated sludge from the downstream to the upstream end of the tank.

Abstract: A modified activated sludge system is provided wherein wastewater containing BOD.sub.5 and phosphate values is admixed in an initial zone with biomass-containing recycled sludge to form a mixed liquor under conditions effecting sorption of BOD.sub.5 in the biomass. Subsequently, said mixed liquor is subjected to aeration in an oxidation zone under conditions for effecting oxidation of BOD.sub.5, such that oxidizing agent is incorporated into the oxidation zone at a rate not substantially exceeding the rate of oxidation. By such operation, considerable savings in power requirements for oxygen transfer to the mixed liquid are had, while developing and maintaining a dense non-bulking biomass having the properties of good removal of phosphate from the wastewater influent.

Abstract: A nitrification process is disclosed wherein the population of the nitrifying bacteria in an activated sludge system may be increased by the addition of ammonium nitrogen to a return sludge reaeration zone. The increased nitrifying population results in increased reliability of nitrification and lower effluent ammonium nitrogen concentrations.

Abstract: A process for activated sludge treatment of industrial wastewaters which uses, in the aeration tank of an activated sludge treatment plant, at least one member of the group consisting of phytic acid, phytate salts and materials containing the same, as well as at least one other phosphorus-containing compound.

Abstract: A method for accelerating the startup of biological nitrification systems for wastewater treatment and preventing or reducing the effects of toxic or inhibitory materials or excursions of pH, temperature or dissolved oxygen upon nitrifying organisms. A rapidly metabolized soluble or miscible organic material containing little or no nitrogen is added to the carbon-consuming step of the process. Heterotrophic organisms consume the added material together with soluble ammonia to generate additional organisms. The soluble ammonia concentration in the wastewater is reduced to a non-toxic, less toxic, or less inhibitory level.

Abstract: An apparatus and method for withdrawing gaseous decomposition products from a refuse dump. Disposed at various locations in the refuse are gas collection mechanisms, such as gas wells, drainage systems, etc., each of which is connected via a gas withdrawal line with a collector, from which the gas is withdrawn for further utilization. Disposed in each gas withdrawal line is a sensor and a regulatable shutoff device. The sensor transmits the content of a characteristic constituent of the gas flow in a given gas withdrawal line to a measuring and control unit, which monitors the gas flow volume as a function of a comparison of the sensor signals with preset threshold values. If the sensors indicate that the content of the characteristic constituent of the gas flow exceeds or drops below the preset threshold values, the measuring and control unit opens or closes the associated shutoff device by an appropriate amount.

Abstract: The bioconverter includes a collecting vessel having a plurality of stirring shafts rotatably mounted therein, each of which is driven by a separate electric motor. Adjacent shafts operate in opposite directions and stirring arms are oriented relative to each shaft moving the carrier mixture within the vessel which is in close proximity to a shaft in opposite directions along adjacent shafts. A moisture sensing device is adapted to be located below the level of the carrier mixture within the vessel for sensing the percentage moisture content of the mixture and waste material added thereto. A first fan is provided for exhausting the air from the vessel and a second fan is provided for moving the air over the surface of the mixture within the vessel. A first heating coil is located on the bottom of the vessel for heating the mixture within the vessel, and a second heating coil is provided adjacent the second fan for heating the air which is blown over the upper surface of the mixture within the vessel.

Abstract: It was found difficult to carry out anaerobic treatment of peroxide-containing wastewater. According to the invention, the problem is solved in that the peroxide content of the water is reduced in a catalytic pretreatment step (1), preferably an enzymatic pretreatment step.

Abstract: The invention relates to a method of treating wastewater from the manufacture of peroxide bleached mechanical or chemi-mechanical pulp. The method comprises a hydrolysis step, a methane fermentation steps and an aerobic step. After the hydrolysis and methane fermentation steps, sludge is separated from the wastewater and partially recycled to the hydrolysis step. The redox potential of the outgoing water from the hydrolysis step is continuously measured and controlled to a value between -400 and -260 mV by regulating the amount of sludge recycled or by passing ingoing wastewater directly to the aerobic treating step.

Abstract: Abnormally lowered reduction in the rate of phosphorus removal from influent wastewater in an activated sludge system, occurring particularly following periods of increase in flow rate of wastewater entering the system, is avoided by controlling the maximum F/M in that portion of the system in which oxidation is occurring so as not to exceed 0.9 and maintaining a defined relation between the maximum and minimum F/M during any 24 hour operating period.

Abstract: This invention pertains to a method for analyzing the biochemical decomposibility of aqueous substrates by microorganisms and particularly to a method for analyzing the quality or biological toxicity of incoming sewage to a sewage disposal plant. The process comprises: placing a preselected amount of bacterial culture, in the form of a dried powder, in contact with a preselected amount of aqueous waste containing greater than 5 mg/l dissolved oxygen, the bacterial culture being capable of effecting aerobic biodegradation of organic waste; measuring the dissolved oxygen content of the aqueous waste during rehydration and respiration development of the microorganisms as a function of time; determining the rate of dissolved oxygen decline at a preselected time; and then comparing the rate of dissolved oxygen decline to the rate of dissolved oxygen for a preselected baseline standard substrate.

Abstract: A method and system for reducing the sulfur concentration of wastewater which is to be disposed of through anaerobic treatment. Wastewater high in sulfur content is fed to a reactor having a pH level less than 6, such that the sulfate and/or sulfite compounds in the wastewater are converted by sulfate reducing bacteria into sulfide gas, thereafter exhausting the sulfide gas from the reactor. It is preferred that two anaerobic reactors be connected in series, such that the first reactor contains sulfate reduce bacteria and/or acid-forming bacteria, and the second reactor contains methane-forming bacteria and/or acid-forming bacteria.

Abstract: A method and apparatus for biological aerobic treatment of wastewater wherein oxygen is induced into a mixed liquor flow path and a method and apparatus for separating the liquid withdrawn from the mixed liquor flow path into a clear liquid stream and a flock laden stream. A streaming specific gravity separator of unique construction and operation separates the mixed liquor into a clear liquid stream and a flock laden stream, withdrawing the clear liquid stream from the system and directing the flock laden stream back into the mixed liquor flow path. The separator functions within the system to be self-controlling for load increases or decreases.In accordance with preferred embodiments of the system, the separator may be positioned inside or outside of an oxidation ditch. The separator may also be utilized in combination with an aeration basin.