Abstract: A water or wastewater treatment system to reduce phosphorus or other pollutant concentrations in water or wastewater may include an optional primary treatment stage in fluid communication with a biological secondary treatment stage. The secondary treatment stage may, in turn, be fluidly connected with a tertiary treatment stage, which may include a chemical treatment portion for reducing phosphorus or other pollutants to desired levels. The precipitated phosphorus and other solids or sludge produced from the chemical treatment portion may be recycled upstream for reuse in the primary, secondary, and/or tertiary treatment stages. Such recycle may reduce the amount of added chemicals required in the tertiary treatment stage to phosphorus or other pollutants to desired amounts.

Abstract: An apparatus for treating particulate biodegradable organic waste includes a thermal hydrolysis reactor receiving the particulate biodegradable organic waste for performing thermal hydrolysis at a temperature of about 130° C. at a pressure at or above the saturated water vapor pressure of the organic waste to produce a slurry including solubilized organic material and residual solids. A pH adjustment means for adjusting the pH of the particulate biodegradable organic waste as necessary to provide an acidic pH of greater than about 3.15 before thermo hydrolysis of the particulate biodegradable organic waste is provided. Separating means receive the solubilized organic material and residual solids for separating solubilized organic material from the residual solids. An anaerobic reactor is configured to receive the solubilized organic material.

Abstract: A method for treating particulate biodegradable organic waste includes sizing the waste and adding a base prior to introducing the waste to a thermal hydrolysis reactor and hydrolyzing the waste at a temperature of about 130° C. or greater and a pressure greater than the saturated water vapor pressure to produce a slurry including solubilized organic material and residual solids. The solubilized organic material is separated from the residual solids using a liquid/solid separator and the solubilized organics are subjected to anaerobic digestion to produce a methane gas. The base is preferably potassium hydroxide (KOH) at a concentration of about 1%. The method may further include preheating the particulate biodegradable organic waste with latent heat of the separated solubilized organic material prior to thermal hydrolysis.

Abstract: Removal of biological nutrients from a wastewater yielding a low phosphorous (e.g., less than 0.25 mg/L) output includes providing a serial multistage bioreactor containing activated sludge having in hydraulic series an anaerobic zone and a downstream aerobic zone, with each zone having an upstream inlet and a downstream outlet. The wastewater is provided to the anaerobic zone inlet. A quantity of chemical sufficient to precipitate soluble and particulate phosphorous is added to the downstream aerobic zone in an amount sufficient to yield a low phosphorous output. Treated water is separated from the activated sludge and precipitated phosphorous and a return activated sludge separated from the treated water is recycled to the anaerobic zone.

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 water or wastewater treatment system to reduce phosphorus or other pollutant concentrations in water or wastewater may include an optional primary treatment stage in fluid communication with a biological secondary treatment stage. The secondary treatment stage may, in turn, be fluidly connected with a tertiary treatment stage, which may include a chemical treatment portion for reducing phosphorus or other pollutants to desired levels. The precipitated phosphorus and other solids or sludge produced from the chemical treatment portion may be recycled upstream for reuse in the primary, secondary, and/or tertiary treatment stages. Such recycle may reduce the amount of added chemicals required in the tertiary treatment stage to phosphorus or other pollutants to desired amounts.