Comparison Study On Phosphorus Removal Between Single-stage Oxic Process And Anaerobic/Aerobic Process

The need to decrease anthropogenic nutrient （especially nitrogen and phosphorus）inputs to aquatic ecosystems in order to control eutrophication. The single-stage oxicprocess is a new type of enhanced biological phosphorus removal approach. Toinvestigate the application foreground of single-stage oxic process performingphosphorus removal. Two SBRs were conducted using acetate and propionate as thesole carbon source, which are the most extensive substrates in the municipalwastewater. The two SBRs were respectively applied with A/O process（SBR1）andsingle-stage oxic process （SBR2）.The two SBRs were conducted using acetate as the sole carbon source, which isthe most extensive substrate in the municipal wastewater. The results obtained duringthree months showed that the phosphorus removal efficiency and the TP removed on aunit MLSS were respectively91.72%and3.23mg·g-（1SBR1）versus71.70%and2.91mg·g^-1（SBR2） during steady operation. The further study found that a substantialincrease of PHA was associated with an obvious decrease of glycogen in SBR1whilea substantial synthesis of PHA was going with an obvious accumulation of glycogenin SBR2, indicating glycogen was not essential for the synthesis of PHA insingle-stage oxic process. Furthermore, obvious phosphorus release was observed inboth SBRs during idle period, but the content of phosphorus released in SBR2wasmuch higher than that in SBR1(13.28mg·L^-1versus2.6mg·L^-1).The possible reasonfor SBR1and SBR2exhibiting different efficiency of phosphorus removal was thatmicroorganisms in both SBRs had a dissimilar cyclic storage and consumptionprocess of energy storages during metabolic process. Besides，the COD/P ration is lowto the single stage oxic process, so SBR1contained less glycogen accumulatingorganisms activities than that by SBR2.When study the propionate as the sole carbon source on biological phosphorusremoval, The results showed that the SBR1and SBR2removed3.25versus3.36mgof phosphorus per g of MLSS during the course of the steady operational trial, and theeffluent phosphorus content was reached0.81±0.17mg·L^-1versus0.53±0.11mg·L^-1,demonstrating the good performance of phosphorus removal. The efficiencies weremaintained around93.6%（SBR1）, versus95.9%（SBR2）. The facts clearly showedthat SBR2could be enhanced by the single-stage oxic process using propionate as the carbon source.The comparison study on phosphorus removal between single-stage oxic processand anaerobic/aerobic process revealed that the single-stage oxic process can developa potentially simple and effective approach for enhanced biological phosphorusremoval.