A biological phosphorus removal potential test for wastewaters

A simple test was proposed to assess whether phosphorus in a wastewater can be removed using a biological phosphorus removal (BPR) process. The test i ncludes the measurement of phosphorus release during 2 hours of the anaerob ic stage in a batch reactor containing phosphorus-accumulating organisms (P AOs) and estimation of the effluent phosphorus concentration using biochemi cal relationships. The BPR potential test developed allowed for the success ful evaluation of BPR feasibility for five wastewater samples. The BPR pote ntial test was validated by comparing the test results with the effluent ph osphorus concentrations measured in a sequencing batch reactor (SBR). An ef fluent phosphorus concentration of 1.9 mg P/L predicted for the BPR potenti al test performed was close to the effluent phosphorus concentration of 1.8 mg P/L obtained from an SBR on the same day. During the anaerobic stage, p hosphorus release was significantly affected by the sludge concentration in itially, but became insignificant after 2 hours. The initial sludge concent ration affected the phosphorus release rate; thus, it is recommended that t he BPR potential test be conducted at a target mixed liquor volatile suspen ded solids concentration. It is also recommended that the BPR potential tes t be conducted at the site where the PAO-containing sludge is available and the wastewater sample can be delivered at 4 degreesC in less than 24 hours . The PAOs in different sludges had almost identical phosphorus release aft er 2 hours: however, the characteristics of facultative bacteria in sludges affected the phosphorus release. If the wastewater is prefermented for at least 3 days before the BPR potential test, the amount of phosphorus releas ed by various PAO-containing sludges is expected to be identical.