Patent ID: 7252765

Claim:
A process for biologically treating wastewater comprising the steps of: a) flowing influent wastewater with organic components therein into a first anaerobic region; b) measuring the average phosphorus content by weight of said influent wastewater; c) measuring the average short chain fatty acid content by weight of said influent wastewater; d) mixing the influent wastewater in said first anaerobic region with a microorganism biomass to form a mixed liquor; e) 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; f) ensuring that the flow of mixed liquor to said second anaerobic region is sufficient to produce enough short chain fatty acids in said second anaerobic region that when combined with the short chain fatty acids in said influent wastewater the total is greater than four times the amount of phosphorus in said influent wastewater by weight; g) 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; h) thereafter flowing mixed liquor from said first anaerobic region to an aerobic region wherein said short chain fatty acids are metabolized by the microorganisms in said biomass and phosphorus is absorbed by said microorganisms; I) thereafter transferring said mixed liquor to a clarifier region wherein clarified liquid is separated from said biomass; and j) returning at least a portion of the separated biomass with phosphorus therein to said first anaerobic region.