TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The chemical is one of an aluminum salt, iron salt and polymer. The quantity of the chemical added to (I) is selected to cause at least one of a desired decrease in phosphorus/nitrogen concentration and a desired increase in the quantity of primary sludge removed in the removing step. The chemical is aluminum sulfate and the quantity of chemical added to (I) is selected to attain a molar ratio of aluminum to phosphorus between 0.1-20 in (I), after the chemical addition or ferric chloride and aluminum sulfate and the quantity of the chemical added to (I) is selected to attain a reduced level of colloidal material in (I), after the chemical addition. The volatile fatty acid enriched effluent has a ratio of volatile fatty acid content to ortho-phosphate content by weight equal to or greater than 7-1. (A) is fermented for 2-8 days to produce greater than 0.1 pounds of a volatile fatty acid for each pound of primary sludge fermented.Preferred Components: The apparatus further comprises a biological phosphate removal system receiving the volatile fatty acid enriched effluent, a biological nitrogen removal system receiving the volatile fatty acid liquor enriched effluent. The means for fermenting comprises a gravity thickener in fluid communication with the primary treatment vessel; and a fermentation tank in fluid communication with the gravity thickener. The biological phosphate removal system comprises an anaerobic zone receiving the volatile fatty acid enhanced effluent, the anaerobic zone having organisms within it which release bound phosphorus and uptake volatile fatty acids to produce energy stores; an anoxic zone receiving an effluent from the anaerobic zone, the anoxic zone having organisms which metabolize the stored energy and uptake phosphorus; and an aerobic zone receiving an effluent from the anoxic zone, the aerobic zone having organisms which metabolize the stored energy and uptake phosphorus. The biological nitrogen removal system comprises an anoxic zone receiving the volatile fatty acid enhanced effluent, the anoxic zone having organisms within it which uptake the volatile fatty acids and reduce nitrate to nitrogen gas; an aerobic zone receiving an effluent from the anoxic zone, the aerobic zone having organisms which convert ammonia to nitrate; and a recirculation loop of a nitrate rich liquor from the aerobic zone to the anoxic zone.