Abstract: The biological water or wastewater treatment process described herein alternates aeration and anoxic phases during a water treatment process. According to one exemplary process, the water or wastewater is directed into a biological tank. The water or wastewater in the biological tank is aerated until measured nitrate or redox values meet high nitrate or high redox set value conditions relative to minimum aeration and maximum aeration time requirements. Subsequently, the water or wastewater is subjected to anoxic treatment until the measured nitrate value meets low nitrate set value conditions relative minimum and maximum anoxia time requirements.

Abstract: A method of treating wastewater wherein the biomass associated with the wastewater is subjected to simultaneous nitrification and denitrification in a single reactor. The method entails directing a wastewater influent stream into the reactor and measuring the concentration of N—NH4 in the influent wastewater stream at a point upstream from the reactor. Air is supplied to the reactor for aerating the biomass in the reactor. The method includes controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—NH4.

Abstract: A method of treating wastewater wherein the biomass associated with the wastewater is subjected to simultaneous nitrification and denitrification in a single reactor. The method entails directing a wastewater influent stream into the reactor and measuring the concentration of N—NH4 in the influent wastewater stream at a point upstream from the reactor. Air is supplied to the reactor for aerating the biomass in the reactor. The method includes controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—NH4.

Abstract: The biological water or wastewater treatment process described herein alternates aeration and anoxic phases during a water treatment process. According to one exemplary process, the water or wastewater is directed into a biological tank. The water or wastewater in the biological tank is aerated until measured nitrate or redox values meet high nitrate or high redox set value conditions relative to minimum aeration and maximum aeration time requirements. Subsequently, the water or wastewater is subjected to anoxic treatment until the measured nitrate value meets low nitrate set value conditions relative minimum and maximum anoxia time requirements.

Abstract: The invention concerns a method and installation for the treatment of excess sludge derived from biological wastewater treatment plants. The method is characterized in that it consists of associating at least one digestion step (4) and at least one wet oxidation step (2) of said sludge, said wet oxidation step being conducted at a temperature of between 50° C. and 180° C. and at a pressure of between 2 and 40 bar.

Abstract: A single tank submerged membrane bioreactor for treating feed water having unacceptable levels of ammonia or total nitrogen has both a membrane scouring bubble supply and an oxygenating bubble supply. The membrane scouring bubble supply continuously provides large scouring bubbles to clean the membranes. Permeate is continuously withdrawn from the membranes at a high rate but the large scouring bubbles do not transfer sufficient oxygen to the mixed liquor to create aerobic conditions in the reactor. The oxygenating bubble supply is operated to provide small bubbles of air or oxygen that intermittently produce aerobic conditions in a significant part of the mixed liquor. Alternating aerobic and anoxic conditions occur in a significant portion of the tank suitable for nitrification and denitrification.

Abstract: The invention relates to a method for checking and regulating the pressure loss in a biological filter of the type comprising an immersed filter bed (2) consisting of at least one layer of granular filtration material, the said granular material layer acting as a support for a biomass used to degrade carbon-based and/or nitrogen-based pollution in water to be filtered, characterized in that it comprises a step consisting of continuously or discontinuously injecting at least one coagulating agent (1) into the said water before its entry into the said filter.

Abstract: The invention relates to a method for regulation of aeration in a biological filter of the type comprising conveyance means (3) bringing water to be filtered into the lower part of the filter, a filter bed (2) acting as a support to the biomass, means of distributing an oxygenated gas (5, 5a) in the filter bed (2), a layer of filtered water (7) above the said filter bed, a nozzle for (4) of discharging the filtered water in the upper part of the filter, characterized in that it consists of taking account of the efficiency Ct with which the biomass uses the distributed oxygen to regulate the said distributed oxygenated gas flow and/or its concentration in molecular oxygen, in order to optimize the quantity of molecular oxygen distributed by the said distribution means.