Abstract: This is a process for wet oxidation of an ammonium salt containing waste liquor which prevents plugging of the vapor-carrying lines of the wet oxidation system. The vapor-carrying lines are maintained in an unobstructed condition by adding sufficient liquid water to dissolve condensed ammonium salt which can plug these lines. This provides for safe operation of the wet oxidation system.

Abstract: A two-stage wet oxidation process for COD removal from high strength wastewater is disclosed. The wastewater stream is treated in a first stage subcritical wet oxidation zone at temperatures between about 250.degree. and 374.degree. C. to remove a substantial portion of the COD. Subsequently, all or a portion of the first stage oxidized waste stream is treated in a second stage supercritical wet oxidation zone at temperatures of 374.degree. to about 600.degree. C. to remove any remaining COD content. Both stages of wet oxidation treatment are carried out at essentially the same system pressure.

Abstract: The invention is a process for starting up a wet oxidation system using essentially pure oxygen for oxidation of a concentrated wastewater. Flow of startup water and air is established through the wet oxidation system at an elevated temperature and pressure. An incremental increase in flow of oxygen and wastewater to the system commences while simultaneously an incremental decrease in flow of startup water and air occurs, raising system temperature in a controlled fashion. The incremental changes in flows are repeated until the wastewater and pure oxygen have reached about 100 percent of selected operating flows, the startup water and air flows have decreased to zero, and the system has attained the selected operating temperature, while maintaining a selected oxygen residual in the offgases.

Abstract: A process for controlling corrosion in a wet oxidation system by controlling the operating pH range within the system is described. A pH operating range is selected within which corrosion to the wet oxidation system is minimized. The pH within the wet oxidation system is monitored and a pH adjusting material is added to the waste material being treated to maintain the system pH within the selected pH operating range, thus minimizing corrosion.

Abstract: A process is described for the operation of a multiple zone batch treatment system for biological or biophysical treatment of wastewater. The system comprises two or more batch treatment zones with wastewater passing sequentially through all treatment zones. After the mix and settle batch steps occur for all zones, influent wastewater flows into the first zone and displaces clarified wastewater in a plug flow mode through each treatment zone and ultimately from the last zone. The combining of the decant and fill steps for all or most of the zones provides for shorter cycle times and greater capacity for the system.

Abstract: A process for treating an aqueous wastewater containing ammonium compounds. The process comprises the steps of preheating a liquid influent and introducing the preheated influent, an oxygen-containing gas an the wastewater into a reaction vessel for undergoing wet oxidation. An oxidized effluent is then withdrawn from the reaction vessel, which includes a gas phase containing ammonia and carbon dioxide and a liquid phase containing the ammonium compounds. The temperature of the effluent is then reduced to a temperature sufficient to condense a substantial portion of the ammonia into the liquid phase, and afterwards the remaining gas phase containing a substantial portion of the carbon dioxide is separated from the resulting liquid phase.

Abstract: An improved apparatus and method for operating a granular medium filter is disclosed. The apparatus comprises an improved underdrain structure made up of a plurality of rectangular compartments which allows the filter bed to be "air pulsed" as well as backwashed for thorough cleaning of the bed. Nozzles are positioned within the rectangular compartments and directed vertically into the filter bed. Fluid from the nozzles helps to break up the bed during backwashing as well as countereact size classification of the medium during this process. The method of operating a filter with the improved underdrain structure is also described.

Abstract: An improved apparatus and process for the operation of a down-flow granular medium bed filter is disclosed. A splash plate for dissipating the force of influent liquid is rotatably connected to support means, allowing the plate to rotate from a position parallel to the bed surface to a position perpendicular to the bed surface upon the liquid above the bed rising to a selected first level. The splash plate is maintained in the perpendicular position for the remainder of the filtration cycle, the backwash cycle and any chemical cleaning cycle, allowing unobstructed operation of the filter bed. The splash plate returns to the original position at the start of another filtration cycle.

Abstract: A process for treatment of caustic sulfide liquor by wet oxidation in a nickel-based alloy system is described. The liquor is first analyzed for alkalinity consuming species and for nonsulfidic alkalinity. If excess alkalinity consuming species is present compared to nonsulfidic alkalinity, then additional nonsulfidic alkalinity is added to the raw liquor such that excess alkalinity is present during wet oxidation treatment, thus preventing excessive corrosion to the nickel-base alloy system.

Abstract: A process for removing color and oxidizable organic matter from thermally conditioned sludge liquor is disclosed. The process comprises treating the liquor with 250 to 430 mg/l chlorine which removes 20 to 70 percent of the color and produces a chlorine residual in the liquor. The chlorine-treated liquor is mixed with a small volume of untreated thermal conditioning liquor to remove the chlorine residual, and the dechlorinated mixture is returned to the treatment plant influent for additional treatment.

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: An improved method for controlling combustion zone temperature in a furnace independent of flue gas oxygen content is disclosed. The method comprises supplying a carrier gas containing a fine mist of liquid water droplets to the furnace combustion zone to control the maximum temperature within the combustion zone. The invention is applicable to both multiple hearth furnaces and fluidized bed furnaces, protecting the refractory furnace lining from damage.

Abstract: An apparatus for controlling the blowdown slurry from a wet oxidation reactor is disclosed. The device includes a pressure control valve with a valve seat and support assembly which extends beyond the valve body to prevent erosion by the blowdown slurry. The apparatus also includes a displacement-compensating seal between the valve and receiving vessel to allow for thermal expansion and contraction during the blowdown cycle while maintaining the integrity of the seal.

Abstract: An improved method for maintaining a granular medium filter in a clean, operable condition is disclosed. The time interval required for the level of liquid above the filter bed to drain from a backwash outlet level to the upper bed surface level following a backwash cycle is monitored. Upon this measured draindown time exceeding a predetermined interval of time, a chemical cleaning cycle is initiated for the granular medium bed filter.

Abstract: An improved method for operating a down-flow granular medium filter is disclosed which increases the effective filtration time between backwashes. The filter tank cell is divided into a plurality of subcells, each individually adapted and controlled for periodic intermittent upwardly-directed pulses of fluid passed through the filter bed within each subcell from an array of orifices beneath or in the bed. During the filtration run, one subcell is pulsed to improve the porosity of that portion of the filter bed while the remainder of the subcells continue to filter wastewater. After initiation of the first pulsing cycle for a subcell, additional subcell pulsing cycles are initiated sequentially. At the end of the filtration run the whole filter cell is backwashed to remove particulate matter from the bed and prepare the bed for the next filtration run.

Abstract: A single-stage continuous aeration-batch clarification process for purifying wastewater containing pollutants includes the steps of continuously aerating the wastewater in the presence of biologically active solids and powdered absorbent in an aeration zone. A portion of the mixture of wastewater, biologically active solids and powdered absorbent is transferred to a settling zone where a settled solids phase and a clarified liquid phase are formed. During the settling step additional wastewater flows into the aeration zone. The clarified liquid phase is discharged from the settling zone while the settled solids phase may be returned to the aeration zone or sent to disposal.The process may be carried out with a single aeration basin and settling basin or with a plurality of aeration basins using a single settling basin.

Abstract: A two-stage process for purifying wastewater includes the steps of biophysical anaerobic treatment to remove the majority of the COD, followed by biophysical aerobic treatment to further purify the wastewater. A powdered adsorbent, preferably powdered activated carbon, is used with biological solids in each treatment step. Excess biophysical solids from the aerobic step are transferred to the anaerobic step for digestion. Fresh powdered adsorbent is added to the aerobic treatment step to compensate for that transferred to the anaerobic treatment step. Solids concentration in the anaerobic step is controlled by wasting solids to disposal.

Abstract: A two-stage, batch process for purifying wastewater containing organic and adsorbable pollutants includes the steps of introducing a predetermined quantity of the wastewater into an aeration and settling zone of a primary treatment zone and aerating therein in the presence of a powered absorbent, such as activated carbon, and biologically active solids, terminating aeration and retaining the thus-treated wastewater in the aeration and settling zone a sufficient time for a substantial portion of the suspended solids to settle by gravity. A predetermined amount of the partialy-treated wastewater is withdrawn from the aeration and settling zone and introduced into a contact zone wherein it is agitated, preferably by aeration, in the presence of a powered adsorbent, agitation is terminated and the solids are allowed to settle by gravity. After completion of settling, clarified, substantially solids-free water is withdrawn from the contact zone.

Abstract: Water contaminated with at least one volatile compound is treated by air stripping the volatile compound into the gas phase, then removing the volatile compound from the gas phase by contacting it with an aqueous mixture of biological solids and powdered adsorbent. The partially-purified water is further treated by a biophysical aerobic process which in turn produces the aqueous mixture of biological solids and powdered adsorbent used to remove the volatile compound from the gas phase. The aqueous mixture of biological solids and powdered adsorbent containing the volatile compound is thickened and the solids slurry treated by regeneration, preferrably wet air oxidation, to destroy the biological solids and volatile compound as well as regenerate the powdered adsorbent. The regenrated adsorbent may be returned to the biophysical aerobic treatment process.

Abstract: A process and apparatus for protecting a media bed filter with underlying support screen from solids contained in a liquid, such as filtrate from the filter, used to regenerate or backwash the media bed filter. Filtrate enters a first collection chamber containing a screen assembly covering one outlet, the chamber also containing a second outlet. Filtrate traverses the screen assembly and is transferred to a second collection chamber with addition of a predetermined amount of bactericide to prevent solids growth therein. Upon bactericide-treated filtrate reaching a predetermined level within the second chamber, filtrate in the first chamber bypasses the screen assembly and flows out the second output to further biological treatment or use. Bactericide-treated filtrate from the second collection chamber is used to regenerate or backwash the media bed filter with addition of optional surfactant to assist in cleaning the filter media and underlying support screen.