Abstract: A method for treating sludge by dewatering to form thick sludge and drying to form dry sludge includes the steps of mechanically predewatering thick sludge to produce predewatered thick sludge and mixing the predewatered thick sludge with non-cooled dry sludge to produce a sludge mixture. The temperature of the sludge mixture to be dried is measured and the dry substance contents of the dry sludge based on the measured temperature is determined. Fluctuations in the dry substance contents of the dry sludge are compensated by controlling the amount of recirculated dry sludge to be mixed with the predewatered thick sludge as a function of the temperature of the sludge mixture to be dried. The sludge mixture is dried to produce dry sludge and a portion of the dry sludge is recirculated to be mixed with the predewatered thick sludge.

Abstract: A dialysis machine is disclosed that incorporates a water treatment module, a dialysate preparation module having a dialysate circuit, and an extracorporeal circuit including a dialyzer and arterial and venous blood lines that connect to the patient. The machine accomplishes on-line disinfection of all the fluid circuits of the machine, including the water treatment module, the dialysate preparation module and extracorporeal circuit, the arterial and venous lines, and the dialyzer, by circulating water heated to a high level disinfection temperature (e.g., 80 degrees C.) through the fluid passages of the machine for a sufficient time (such as an hour) to achieve high level disinfection. After the dialysis session is ended, the patient connects the arterial and venous lines to ports in a disinfection manifold that places the arterial and venous lines into fluid communication with the heated water. Thereafter, the machine is ready to disinfect the fluid circuits including the extracorporeal circuit.

Abstract: An ultraviolet-based or dual mode water purifying system operates under household water pressure to provide a batch treatment of contaminated water. Treated water is stored in a pressurized reservoir, from which it may be released for use. A treatment cycle is initiated by a drop in pressure within the system, which occurs when sufficient water has been withdrawn from the reservoir. The pressure drop is detected by a pressure gauge linked to a UV lamp dimmer, which causes the UV lamp to change from a reduced-output standby mode to an operative mode. The dimmer may be further linked to a thermostatic switch positioned adjacent the lamp, to reduce the output of the lamp when the temperature exceeds a predetermined level, and to a backwash event control, to increase the lamp output to the operative level during filter backwash.

Abstract: A high temperature, short time microwave heating system 10 for heat-sensitive liquid material to inactivate or reduce pathogenic agents or organisms, such as viral contaminants. The system 10 includes a disposable cartridge 26 consisting of a preheater 32, a microwave heating coil 56 and cooler 58 with the heating coil 56 adapted to be easily inserted in and removed from the microwave heating field.

Abstract: An improved method and apparatus for removing chemical contaminants from soil. Contaminated soil is loaded and hydraulically sealed in the treatment vessel. A vacuum is placed on the material, which is indirectly heated through the heat transfer plate from a natural gas of propane fired burner located under the plate. As the material is heated, contaminants are vaporized and flow through the vacuum discharge pipe toward the condenser unit. Vapors are cooled in the condenser through a series of refrigerated condensing coils where the vaporized material is converted back to a liquid and discharged to a liquid recovery vessel. After treatment, material is downloaded into a roll-off type container for post-treatment analysis and cool down prior to recycling or backfilling. Recovered liquids are recycled or sent to an appropriate facility. Process time is typically 45 minutes to an hour for a six cubic yard batch. The system is self-contained, mobile, and operable by a two-person crew.

Abstract: The water remediation and purification method includes a cavitation nozzle which is operated with a throat size and pressure drop to incur cavitation in the water. The explosive and implosive bubble growth and collapse produces free radicals which interact with contaminants in the water to oxidize the contaminants. The cavitation process is enhanced by (1) a variable throat nozzle, (2) recycling the product back through the nozzle for further oxidation, and (3) programmable control feedback. Subsequent ultraviolet radiation from high energy lamps, ion exchange and/or degassifying treatment can be employed to produce water quality within acceptable levels.

Abstract: A filter medium is backwashed to cleanse it of cake when a fluid pressure difference across the filter medium rises to a predetermined degree. Since the pressure difference is subject to change not only with the amount of the cake but also with the temperature and flow rate of the fluid being filtered, not only the pressure difference but also at least either of the fluid temperature and flow rate is constantly monitored. A correction coefficient circuit is provided which has stored thereon pressure difference characteristics at various temperatures and/or flow rates of the fluid including a pressure difference at a rated temperature and/or rated flow rate. The correction coefficient circuit computes a correction coefficient by comparing the pressure difference characteristic at the monitored temperature and/or monitored flow rate of the fluid with the pressure difference characteristic at the rated temperature and/or rated flow rate of the fluid.

Abstract: Peritoneal dialysis systems and methods move liquid using a pump chamber that is operated in response to pneumatic pressure variations applied by a pump actuator. The systems and methods periodically measure air pressures in the actuator and an associated reference air chamber and derive from these a measurement of liquid volume moved through the pump chamber. The systems and methods minimize derivation errors by compensating for temperature differences among the pump chamber; the pump actuator; and the reference chamber.

Abstract: A process for the production of a durable granular or pelletized sludge product is disclosed whereby a minimal amount of high calcium oxide material is utilized for pathogenic stabilization, a portion of the resulting hot mixture being recycled back to the mixing stage to reduce the requisite lime consumption by utilizing unreacted lime, for energy recovery and to increase dryness.

Abstract: An automatic grease interceptor for separating grease, fats and oils from wastewater is disclosed. The interceptor includes an interceptor chamber having an inlet, an outlet chamber with an outlet and a removable baffle positioned within the interceptor chamber. A grease removal device is attached to the interceptor chamber for removing accumulated grease from the interceptor chamber. A grease level sensor is positioned within the interceptor chamber at a first threshold level, wherein an indication of grease at the first threshold level by the first grease level sensor will activate the grease removal mechanism to thereby automatically remove grease from the interceptor chamber.

Abstract: A process for the treatment of liquids containing sulfides comprising moving at least one injection wand into a tank containing the liquid to be treated, wherein the angle between the injection wand and the tank bottom or the angle between the injection wand and the wall of the tank can be altered, and injecting a treating solution through the injection wand to increase the reaction mixing between the injected treating solution and the liquid being treated.

Abstract: An automatic system to precisely maintain bactericidal action in a reservoir of water equipped with a recirculation system, such as a swimming pool, decorative fountain, spa, cooling water reservoir or the like. The automatic system includes: a service loop which bypasses a portion of the recirculating water past sensors which measure the pH and oxygen reduction potential (ORP) of the water and in which acid and halogen are injected by a chemical feed unit; an electronics unit for determining the injection quantity of the acid and/or halogen needed to restore pH and ORP to stored set-points, and for controlling the chemical feed unit in response to the injection time determination; and an optional telecommunication unit for reporting process control status to a remote location and allowing modification of the process parameters, selection of operating modes, and performance of diagnostic tests from the remote location.

Abstract: Apparatus is disclosed for maintaining the temperature of waste water entering a grease trap below a preset temperature. The apparatus is useful to prevent grease which has collected in the grease trap from being washed into the sewer system by persons attempting to flush the grease from the trap with hot water. A temperature sensor monitors the temperature of waste water flowing into the grease trap. Cold water is introduced directly into the waste water conduit, upstream of the trap, through a valve controllably coupled to the temperature sensor whenever the temperature of waste water in the waste water conduit exceeds a threshold temperature.

Abstract: An energy efficient water purification system which maintains critical operating temperatures for effective reverse osmosis. The system includes hot and cold water inlets providing a flow of heated feed water, a regeneratable pre-treatment system for treating the heated feed water, a reverse osmosis machine for receiving the flow of pre-treated feed water heated to a given temperature to purify the feed water and discharge impurities in a discharge stream and feed the purified feed water to an outlet for end use, and a valve to control the temperature of the heated feed water entering the pre-treatment system, and an energy conserving apparatus comprising a valve arrangement which interrupts the heated water flow into the pre-treatment system and substitutes fresh unheated feed water during regeneration.

Abstract: The water remediation and purification apparatus includes a cavitation nozzle which is operated with a throat size and pressure drop to incur cavitation in the water. The explosive and implosive bubble growth and collapse produces free radicals which interact with contaminants in the water to oxidize the contaminants. The cavitation process is enhanced by (1) a variable throat nozzle, (2) recycling the product back through the nozzle for further oxidation, and (3) programmable control feedback. Subsequent ultraviolet radiation from high energy lamps, ion exchange and/or degassifying treatment can be employed to produce water quality within acceptable levels.

Abstract: The feature of the present invention resides in that when a polyelectrolyte coagulant is added to sludge to dewater the sludge in a sewage treatment plant, the dosage level of the polyelectrolyte coagulant to be to the sludge is controlled most properly, whereby moisture content of dewatered cake can be minimized.

Abstract: A method of and a system for monitoring circulating water systems for conditions susceptible to deposition of a variety of scaling deposits. The invention includes presenting upset conditions at a surface area in the circulating water stream, or in a sidestream in a conduit connected to the main circulating water system, and closely monitoring either heat transfer rate or heat transfer resistance at the water contact surface adjacent the area of upset. When conditions for scaling are present, the upset conditions tend to cause formation of scale deposits at the upset area before the scaling occurs in the main circulating water stream, permitting countermeasures to be taken which inhibit scaling. In the specific case of boilers, heat exchangers or cooling towers, CaCO.sub.3 scaling is monitored at an area where the upset conditions are present, the upset conditions are an increase in the heat transfer rate. The solubility of CaCO.sub.

Abstract: An improved process for oxidizing industrial spent caustic streams, whereby oxidation of spent caustic occurs in a unitary processing tower with three chambers that cooperate simultaneously to oxidize the caustic in the first chamber; to separate the caustic from the oxidizing gas in the second chamber; and, in the third chamber, to pass gas and cooled caustic through a mass transfer apparatus that cools and cleans the gas and releases the caustic and gas into a gas-liquid separation zone of the upper chamber. An alternative embodiment of the invention involves spatially separating the upper chamber from the other two chambers.

Abstract: A method for automatic dispensing of chlorine in swimming pools where a computer measures the pool water temperature, and an empirically derived table is used for the computer to select a temperature related volume unit figure for chlorine dispensing, which volume unit figure is adjusted according to a first step calibration of the chlorine dispensing device and a second step calibration according to the water volume of the existing pool.

Abstract: A method and process for the treatment of liquids, including moving injection wands into a tank containing the liquid to be treated and injecting a treating solution through the injection wands to increase the reaction mixing between the injected treating solution and the liquid being treated.

Abstract: The concentration of amorphous silica in an aqueous solution is monitored to determine a concentration above which silica will precipitate. The precipitation concentration is data processed with a means for data processing by solving the Setchnow equation for aqueous solutions containing silica. The means for data processing generates a signal that, if need be, can be used to automatically adjust the parameters of the system to prevent silica precipitation or to carefully control the precipitation rate. An alternative embodiment provides a method for determining amorphous silica concentration, then data processing the solution to the Setchnow equation, generating a signal, and adjusting the parameters of the system. The apparatus and method of this invention are particularly useful in geothermal power plants.

Abstract: An apparatus for coagulating treatment which is capable of controlling the amount of addition of a coagulant to the optimum level thereby minimizing the water content of the dehydrated cake comprises coagulant adding devices (6), (7), and (8) for causing the coagulant to be added in a variable amount to a liquid subjected to the coagulating treatment, a heat transfer detecting meter (12) disposed so as to contact the liquid to which the coagulant is to be added, the liquid to which the coagulant has been added, or the filtrate from the liquid to which the coagulant has been added and adapted to detect a feeble change in the physical property of the liquid in the form of a change in voltage, and a control device (16) for controlling the amount of addition of the coagulant in the coagulant adding device (8) so that the value of detection of the heat transfer detecting meter (12) is minimized or kept within a desired range.

Abstract: The invention is directed to an apparatus and method for transforming a sterile pyrogen-free liquid into a substitution liquid using an exchanger. The method includes the steps of flowing first and second liquids over opposite sides of a semipermeable membrane, the first liquid being sterile and pyrogen-free. Both liquids contain at least some electrolytes of blood including at least a buffer agent or a precursor of a buffer agent. At least some of the electrolytes have different concentrations in the two liquids. When purifying blood by hemodiafiltration, this method has the particular advantage that, rather than discarding the second liquid, it can be used for hemodiafiltration.

Abstract: The present invention provides an extractive separation method in which a solute contained in a medium can be efficiently extracted and separated with a lower consumption of energy under the remarkably gentle operating conditions. This method consists in that a medium containing a solute consisting of organic substances is brought into contact with a solvent consisting of organic substances or inorganic substances, which have the critical temperature of 5.degree. to 152.degree. C.

Abstract: A tri-modal filter canister adapted to contemporaneously remove both entrained water and suspended solid particles from non-aqueous fluids, said water and particulate removal functions being separate and substantially severable within said filter canister.

Abstract: Automatic treatment of a drain system is provided by the controlled injection of a bio-active liquid at established intervals into the drain system. A container of the treatment liquid is provided with a pump coupled between the container and the drain. Fluid level sensing means is located in the container and fluid temperature sensing means is located in the drain system. When the temperature is within range and the fluid level is sensed, the pump is periodically operated to inject a quantity of fluid directly into the drain system without operator control.

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: A method for more selectively removing macromolecules from a plasma solution, whereby plasma containing the macromolecules to be removed is provided and heated to a temperature near or above normal body temperature but below the boiling point of the plasma solution. The heated plasma solution is filtered while at a temperature near or above normal body temperature but below its boiling point with a membrane filter to remove selectively macromolecules from the plasma solution. An apparatus for accomplishing the foregoing is also provided.

Abstract: A water treatment system is provided including a service step, a regenerating step and a rinse step. The service step includes introducing water to be treated into the inlet, through a treatment medium and out the outlet to a service location. If a prolonged period of idleness is determined automatically, a rinse step is automatically provided by which an amount of water to be treated is introduced into the inlet, through the treatment medium and out of the outlet to drain.

Abstract: A method for starting up and controlling the temperature of a wet oxidation process in which a heat exchanger employing superheated steam is used to initially heat a waste stream introduced into a wet oxidation reaction vessel for start up and then to subsequently adjust the temperature of the waste stream, after it is preheated by the effluent from the reaction vessel, to a level suitable to maintain steady state operation of the reaction vessel.

Abstract: A procedure and means for filtering and homogenizing liquid substances and for automatic cleaning of the filters. In the procedure are utilized an ultrasonic generator (4) connected in conjunction with the filter unit (1; 2) and ultrasonic oscillators (1.11; 2.11) thereto connected, their power and frequency being controlled on the basis of the differential pressure present across the filter units (1; 2), the liquid pressure acting in the filter unit, the liquid flow rate, signals from liquid temperature pick-ups. In order to enhance the cleaning event of the filter elements (1.2; 2.2) taking place with ultrasonics, the filter unit (1; 2) is emptied during the cleaning phase, making use of compressed air conducted into the filter. In order to facilitate the liquid filtering event and to reduce the need of cleaning action with ultrasonics, during normal filtering an ultrasonic power is maintained which is sufficient for homogenizing the liquid.

Abstract: A method for treating polluted material such as industrial waste water or polluted water from other sources, sewage or sewage sludge or other forms of sludge, or polluted soil, to degrade oxidizable substances therein, comprising subjecting the polluted material to a wet oxidation process in a reactor so as to decompose and/or modify oxidizable substances therein and optionally improve the filterability of solids when present in the material; the material may optionally be pretreated so as to facilitate the wet oxidation process. Solid polluted material is preferably in the form of a liquid suspension, such as an aqueous suspension, when subjected to wet oxidation. The wet oxidation process is performed to such an extent, optionally with subsequent substantial removal of heavy metals, that the decomposed and/or modified substances remaining after the wet oxidation and the optional removal of heavy metals are substantially biodegradable.

Abstract: Liquid purification apparatuses and methods; an open filtration, treatment and siphon apparatus and process; a porous mass formation apparatus and process; and a liquid-solid separation apparatus and a process using a siphon member. In one embodiment, a liquid or liquid containing mass, gel, or mud having solids is contained in or introduced into an upper vessel. The liquid and particles of undissolved solids are drawn away from the upper vessel by siphonage. Particles of solids may either settle to the bottom of the upper vessel, remain in the liquid or mass, or float to the top of the surface in the upper vessel. Particles of undissolved solids may be deposited in a siphon member of porous media as the liquid and particles of undissolved solids flow through the porous media.

Abstract: A method and apparatus for dewatering material, the material having a certain degree of conductivity, the material being introduced into a pressure chamber and simultaneously being compressed as electrical energy is introduced into the material elevating the temperature and driving off the fluid or water in the form of steam through apertures in the pressure chamber, the residence time being a function of the conductivity of the material, the dimensions of the pressure chamber and the electrical energy and pressure directed on the material.

Abstract: A water softening system is provided including a service step, a regenerating step and a rinse step. The service step includes introducing relatively hard water into the inlet, through an ion exchange resin and out the outlet to a service location. The regenerating step includes introducing a brine solution into the inlet, through the resin and out the outlet to drain. Prior to the service step, an automatic rinse step is provided by which an amount of the relatively hard water is introduced into the inlet, through the softening medium and out of the outlet to drain.

Abstract: A method for determining the level of heavier particulate waste material in a storage tank of liquid. The method comprises mounting a heated sensor below an unheated or reference sensor so that the reference sensor is influenced under some circumstances by the heater, but is insulated therefrom when the heated sensor is embedded in the particulate material. The invention includes the apparatus for accomplishing the method.

Abstract: A method for more selectively removing macromolecules from a plasma solution, whereby plasma containing the macromolecules to be removed is provided and heated to a temperature near or above normal body temperature but below the boiling point of the plasma solution. The heated plasma solution is filtered while at a temperature near or above normal body temperature but below its boiling point with a membrane filter to remove selectively macromolecules from the plasma solution. An apparatus for accomplishing the foregoing is also provided.

Abstract: A cooling tower system and associated method is disclosed for controlling an aqueous coolant circulated through a cooling tower without requiring discharge of the coolant during recirculation. The coolant pumped from the cooling tower is filtered and monitored for characteristics. Generally acceptable levels of pH, temperature and TDS are maintained in the coolant to reduce the corrosive and scale-forming tendencies thereof and with those levels being maintained and monitored, the calcium content of the coolant is then adjusted in order to balance the Langelier Saturation Index (Sl) at a zero level. A computer is programmed to resolve control algorithms for Sl=0 and, using stored tabular data corresponding to the respective values of the monitored characteristics of pH, temperature, alkalinity and TDS, the computer calculates the value of calcium necessary to maintain a zero index.

Abstract: A process for treating sewage sludge having a predetermined water content to produce a soil conditioner, comprising (a) transporting the sludge aboard a vehicle; and (b) heating the sludge during the transporting step (a) to a temperature and for a time sufficient to pasteurize the sludge without substantially reducing the water content of the sludge. The treatment is conducted aboard any suitable vehicle, such as a ship, railroad car or truck. The heat required to pasteurize the sludge may be obtained from the vehicle's engine waste heat and/or an auxiliary heat source. The sludge is pasteurized during the vehicle's transit from one destination to another and thereby eliminates the requirement of performing a separate pasteurization process before the sludge has been loaded on the vehicle or after it has been unloaded from the vehicle. The present invention protects the public health and saves both time and money as compared with conventional processes of the prior art.

Abstract: A method and apparatus for disposing of waste water above ground is disclosed. Effluent is deposited in a first tank wherein solids are broken down and liquified by a primary preconditioning unit. The preconditioned effluent is transferred to a second tank. A secondary conditioning unit in the second tank suspends liquid and solid particles in the tank air and vapor, vaporizes the suspended liquid and any entrained solid particulate material, and then discharges the vaporized material into the ambient atmosphere. An automatic control means senses vapor temperature and operates a stack damper and vacuum means which causes the vapor stream, thus preventing escape of non heat-treated vaporized materials. Another automatic control means activate the secondary treatment unit heater only when the liquid level of the second tank is within a preselected range.

Abstract: A filter centrifuge has a feeler arm which contacts the free surface of the centrifuge contents to signify by the angular displacement of the arm, the thickness of the layer of contents in the filter drum. On the contact surface of the filter arm, at least one sensor is provided which is responsive to a characteristic of the material constructed by the arm for signalling the nature of the material.

Abstract: Gaseous ozone is admixed and stored with water under such conditions that the density of ozone in the water is increased above the normally obtained and held stabily at such levels so that it may be efficiently transported through the processing plant being cleaned. Specifically, the present invention provides for the chilling of the ozone and water carrier to increase density and permit the subsequent increase in temperature to cause propulsion of the water and ozone through the plant to be cleaned in-place.

Abstract: An apparatus for treating blood in an extracorporeal circuit for hemodialysis of hemofiltration and a method for withdrawing heat from blood in an extracorporeal circuit wherein blood is brought into contact along a membrane with a treatment solution which has been heated to a temperature in a source making the treatment of fluid available such that the energy balance of the patient is maintained, the temperature of the source being controlled in that the temperature of the blood emerging from the patient is measured, the temperature value obtained is compared with a predetermined temperature value and on determination of a difference between the two values the source temperature is changed.

Abstract: The disclosed method and apparatus simultaneously purifies air and water contained in an indoor institution such as an indoor swimming pool facility. Air from the interior of the institution is first treated in a cyclone to remove dust, bacteria and odors, then mixed with ozone generated from a separate air source to form an air-ozone mixture which is distributed in the form of fine bubbles in an air/water contact sterilizing chamber. Water from the pool of water in the indoor institution is filtered and transferred to the sterilizing chamber. In the sterilizing chamber, contact of the filtered water and air-ozone mixture acts to simultaneously purify both. The purified air is returned to the indoor institution after moisture removal, ozone elimination and temperature adjustment. Similarly, the purified water is returned to the pool of water after ozone elimination, temperature adjustment and chlorination.

Abstract: A bath water heater and circulator-purifier apparatus that removes microorganisms and other organic substances found in bath water and maintains the temperature of water at a given level without changing water.An apparatus according to the present invention comprises a removable filter for filtering bath water pumped up from a bath tub, a heater for heating the pumped up water, a temperature sensor for controlling the heater, an ejector for ejecting the filter and heated water into the bath tub with air bubbles having a cleansing and skin-stimulating effect and a container for adding to the bath water a water purifying agent having an effect of separating and agglomerating organic substances as well as an effect of sterilizing and deodorizing bath water and suppressing generation of steam.

Abstract: A valve including a heat sensitive actuator which operates to close the valve when the temperature of the fluid flowing therethrough exceeds a predetermined value but which may be quickly restored to operable condition by flowing a cooling fluid around the actuator.

Abstract: A water quality monitor computer (10) repeatedly accesses transducers (12) which monitor physical properties of a water system, such as total dissolved solids, pH, and the like. The water quality monitor computer determines from the monitored water conditions when bleeding or the addition of water treatment chemicals is required. An energy and water management computer (20) periodically accesses the water quality computer and operates valves and pumps (22) to bleed the system or add chemicals, as is appropriate. The management computer further monitors the quantity of chemical supplies on hand with chemical inventory transducers (24), the amount of electrical energy consumed with kilowatt transducer (28) and the like. The energy and water management computer controls energy usage and stores energy and chemical consumption data in a memory (40).

Abstract: The device for reducing the volume of an aqueous waste effluent includes a holding tank, a heating tank for receiving waste effluent from the holding tank and including a heater for heating the waste effluent to a predetermined temperature which is below the boiling point of water and high enough to cause a portion of the water to evaporate and be discharged as water vapors, an agitation pump for continuously recirculating the liquids contents of the heating tank and filter units mounted on top of the heating tank for separating solids and particulate matter from the resulting slurry and returning the filtrate to the heating tank.

Abstract: A filter assembly for removing particles from a fluid which comprises first and second filters, each having a porous filter medium. The mean pore diameter of the porous filter medium of the second filter is greater than the mean pore diameter of the porous filter medium of the first filter. The filter assembly further comprises structure for directing the fluid serially through the first filter and then through the second filter, a mechanism for sensing the temperature of the fluid, and a valve arranged in parallel with the first filter and serially with the second filter. The valve is coupled to the temperature-sensing mechanism so that at least a portion of the fluid is directed around the first filter in response to a predetermined fluid temperature. For example, in the illustrated embodiment, the fluid is directed around the first filter when the fluid temperature is below a predetermined value.

Abstract: The subterranean treatment apparatus and methods disclosed herein are useful for treating various waste streams, including municipal and industrial streams. The disclosed apparatus and methods are particularly useful in determining and controlling the temperature of the reaction zone in a deep well reaction apparatus while avoiding fouling of thermocouples and permitting easy service and replacement. In the disclosed embodiment, a fluid quiescent zone is created in the heat exchanger of the treatment apparatus located within the reaction zone and the temperature is used to control the system by operation of the heat exchanger or control of the C.O.D. of the influent.