Abstract: A wastewater treatment process wherein a portion of a mixture of influent waste water and biomass are transferred from a first anaerobic region to a second anaerobic region having a relatively long retention time in order to produce additional very short chain fatty acids therein which are thereafter returned to the first anaerobic region so that biomass therein takes up the very short chain fatty acids. The contents of the first anaerobic region thereafter flow downstream into an aerobic region wherein the biomass takes up phosphorus. A portion of the biomass is returned to the first anaerobic region and a second portion of the biomass is wasted with phosphorus therein, thereby removing phosphorus from the wastewater being treated.

Abstract: A wastewater treatment process wherein a portion of a mixture of influent waste water and biomass are transferred from a first anaerobic region to a second anaerobic region having a relatively long retention time in order to produce additional very short chain fatty acids therein which are thereafter returned to the first anaerobic region so that biomass therein takes up the very short chain fatty acids. The contents of the first anaerobic region thereafter flow downstream into an aerobic region wherein the biomass takes up phosphorus. A portion of the biomass is returned to the first anaerobic region and a second portion of the biomass is wasted with phosphorus therein, thereby removing phosphorus from the wastewater being treated.

Abstract: A process and installation for the removal of organic matter, phosphate ions and nitrogenous compounds from sewage wastewater. The installation comprises a raw sewage feed line 12 shown feeding into a primary separation basin 14. The primary separation basin 14 has an overflow flow line 16, discharging separated effluent to an attached growth fermentation vessel or fermenter 18. The fermenter 18 is filled with solid supports 20 with sufficient voids therebetween to allow the effluent to pass through the supports 20 and to allow for the growth of fermenting bacteria (not shown) on the supports 20. The supports 20 are shown diagrammatically in the drawings, and can be in the form of rotating discs, hanging or suspended ropes which move as the liquid is passed through the system, a fluidized bed in which the solids are kept in suspension by upward movement of the liquid, rings, slats or plates. The liquid effluent then passes out of the fermenter 18, through flow line 26, for further processing.