Abstract: A reactor and control method for maximizing nitrogen removal and minimizing aeration requirements through control of transient anoxia and aerobic SRT, repression of NOB, and control of dynamic DO concentrations or aeration interval by keeping the reactor NH4 and NOx concentrations approximately equal. Controls are provided for maximizing the potential for TIN removal through nitrification, limited nitritation, nitritation, denitrification, limited denitritation, denitritation making use of 1) real time measurement of ammonia, nitrite, nitrate, 2) operational DO and the proper use of DO setpoints, and 3) proper implementation of transient anoxia within a wide range of reactor configurations and operating conditions.

Abstract: An apparatus and method for selecting and retaining solids in an activated sludge process for the improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size or compressibility. The screens are used to separate and select for slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process.

Abstract: An apparatus and method for selecting, retaining or bioaugmenting solids in an activated sludge process for improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size, compressibility or shear resistance. The screens are used to separate and select slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process. A swapping screen arrangement provides another means of selecting various particles. The exposed shear rate or time, particle compression, or SRTs can be adjusted manually and/or automatically in response to detected readings from an instrument such as a spectrophotometer or other optical approaches to optimize selection of organisms.

Abstract: A reactor and control method thereof for nitrogen removal in wastewater treatment achieves a measured control of maintaining high ammonia oxidizing bacteria (AOB) oxidation rates while achieving nitrite oxidizing bacteria (NOB) repression, using various control strategies, including: 1) ammonia and the use of ammonia setpoints, 2) operational DO and the proper use of DO setpoints, 3) bioaugmentation of a lighter flocculant AOB fraction, and 4) proper implementation of transient anoxia within a wide range of reactor configurations and operating conditions.

Abstract: One or more reactor and one or more control methods are used for nitrogen removal in wastewater treatment to achieve measured control of maintaining high ammonia oxidizing bacteria (AOB) oxidation rates while achieving nitrite oxidizing bacteria (NOB) out-selection, using various control strategies, including: 1) ammonia and the use of ammonia setpoints; 2) operational DO and the use of DO setpoints; 3) bioaugmentation of anammox and lighter flocculant AOB fraction; and 4) implementation of transient anoxia in several reactor configurations and conditions for removal of oxidized nitrogen using anammox or heterotrophic organisms.

Abstract: An improved process for sludge treatment includes anaerobic digestion followed by post-mesophilic aerobic and/or anoxic digestion. The first anaerobic step may be performed under either mesophilic or thermophilic conditions. The subsequent aerobic/anoxic digestion may be performed using either simultaneous, sequential or pulsed aerobic and anoxic conditions. An apparatus for performing the improved sludge treatment may be one digester for performing the anaerobic followed by aerobic/anoxic digestion. Alternatively, the system for performing the improved sludge treatment techniques may be at least two digest reactors.

Abstract: An efficient system and process for removing nitrogen from wastewater while enriching seed sludge in the mainstream treatment process. Bioaugmentation of seed autotrophic organisms facilitate the nitrification reactions by enhancing the rates of reaction advantageously within a smaller volume or within a shorter activated sludge solids retention time. Likewise, bioaugmentation of seed denitrification organisms will also enhance rate of reaction within a smaller volume or shorter activated sludge solids retention time. Separate treatment of high ammonia digester reject water is an efficient method to treat nitrogen in recycle streams as well as to enrich the seed nitrifying and denitrifying cultures.

Abstract: An apparatus using activated sludge for the removal of biological nutrients from a wastewater includes a bioreactor for containing a mixture of wastewater under treatment and activated sludge. The bioreactor is divided into a plurality of serially connected treatment zones and includes a wastewater inlet, a downstream aerobic zone and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone. A method for removal of nutrients from a wastewater includes providing a wastewater to an inlet of a serial, multi-zone, activated sludge bioreactor containing an activated sludge. The bioreactor has a downstream aerobic zone from which water is removed and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone.

Abstract: A Method of treating sludge prior to dewatering by mixing with the sludge a cationic metal in the form of an iron or aluminum slat along with a cationic polymer. The addition of the iron or aluminum salt substantially reduces the amount of polymer required for acceptable dewatering, thusly significantly reducing the cost of the dewatering process. The method is enhanced by subjecting the prior digested sludge to mesophilic aeration prior to the cationic metal salt and polymer being added.

Abstract: An apparatus using activated sludge for the removal of biological nutrients from a wastewater includes a bioreactor for containing a mixture of wastewater under treatment and activated sludge. The bioreactor is divided into a plurality of serially connected treatment zones and includes a wastewater inlet, a downstream aerobic zone and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone. A membrane filter is provided in the downstream aerobic zone so that it functions as an immersed membrane filter with a bioreactor containing an operative volume of wastewater and activated sludge. The immersed membrane filter filters treated water flowing from the bioreactor through a first outlet. An aerator is operative associated with the membrane filter for purging solids from the membrane filter.

Abstract: An apparatus using activated sludge for the removal of biological nutrients from a wastewater includes a bioreactor for containing a mixture of wastewater under treatment and activated sludge. The bioreactor is divided into a plurality of serially connected treatment zones and includes a wastewater inlet, a downstream aerobic zone and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone. A membrane filter is provided in the downstream aerobic zone so that it functions as an immersed membrane filter with a bioreactor containing an operative volume of wastewater and activated sludge. The immersed membrane filter filters treated water flowing from the bioreactor through a first outlet. An aerator is operative associated with the membrane filter for purging solids from the membrane filter.