BioPRS™ – BioDISC™ Phosphorous Removal System
The BioPRS™ is a new approach to solving the problem of meeting lower regulatory limits on effluent total phosphorous. This innovative approach combines chemical phosphorous removal with cloth media tertiary filtration but in a way that does not decrease the capacity of the main biological treatment process and secondary clarifiers. This is accomplished by providing for the chemical treatment of the clarified wastewater after the secondary clarifiers before final polishing by the BioDISC™ cloth media tertiary filtration system. The resultant concentrated high-solids backwash from the BioPRS™ can then be discharged back to the front of the plant, same as conventional filtration, or discharged directly to the sludge handling system.
The process consists of metal salt addition which bounds with the orhto-phosphate to form an insoluble particle. This metal salt addition has a second benefit where it acts as a coagulant and pulls other material out of solution and starts to form small pin floc which helps to remove the phosphorous containing biological cell material thus helping lower total phosphorous. After high energy mixing to ensure complete contact of the metal anions with the ortho-phosphate, an activated diluted polymer solution as added with gentle mixing to start entraining the pin flocs into large floc particles. The flow then enters a quiescent zone where the floc chains are allowed to fully form before introduction into the BioDISC™ clothe media filtration area where this material is entrained on the cloth. As with cloth media filtration, as the schmutzedecke builds up the filtration efficiency increases, thus increasing total phosphorous removal.
