Patent ID: 7285215

Claim:
A process for biologically treating wastewater comprising the steps of: a) collecting wastewater for treatment in a waste water influent region; b) flowing influent wastewater from said waste water influent region with organic components therein directly into a first anaerobic region and mixing the wastewater therein with a microorganism biomass to form a mixed liquor; c) flowing a portion of the mixed liquor into a second anaerobic region wherein said biomass ferments portions of said organic components so as to produce short chain fatty acids; d) producing sufficient short chain fatty acids in the second anaerobic region, such that when combined with short chained fatty acids in the influent wastewater, the total short chain fatty acids are greater by weight than phosphorous in the influent wastewater; e) returning liquid from said second anaerobic region with said short chain fatty acids therein to said first anaerobic region wherein phosphorus is released from microorganisms in said biomass in said mixed liquor and short chain fatty acids are taken up by the microorganisms in said biomass; f) thereafter flowing the mixed liquor from said first anaerobic region to an aerobic region wherein said short chain fatty acids are metabolized by said microorganisms in said biomass and phosphorus is absorbed by said microorganisms; g) thereafter transferring said mixed liquor to a clarifier region wherein clarified liquid is separated from said biomass; and h) returning at least a portion of the separated biomass with phosphorus therein to said first anaerobic region.