Phosphorus And Nitrogen Removal Process Optimization And Analysis Of A Sewage Plant In Wuhan

In view of the current domestic situation that the effluent implementation ofurban-area sewage treatment plant is Grade I, Standard B of Discharge standard ofpollutants for municipal wastewater treatment plant (GB18918-2002), however, theeffluent of water-body potable water shall attain Grade I, Standard A. Hence theupgrading and transformation of existing urban-area sewage treatment plant haveimportant significance of water-environment protection.Based on problems arising in the Phase I operation period of a sewage treatmentplant in Wuhan, model test is utilized to make contrastive analysis of advantages anddisadvantages of A2/O technology and inverse A2/O technology under low-loadcondition, explore the approaches of low-temperature high-effective denitrogenationand denitrifying dephosphatation and provide theoretical basis and technical supportfor the later-period debugging operation of the sewage treatment plant.Under the same low-load condition of water-inflow water quality, the researchshows that A2/O technics is more likely to generate aging of sludge comparing withinverse A2/O technics while NH3-N average effluent amount of inverse A2/O technicsand A2/O technics are8mg·L-1and2mg·L-1separately. Therefore, the plant’sextension technics selected reverse A2/O technics. In the meanwhile, in order toimprove denitrification efficiency, through experimental research, when watertemperature is less than or equals to5degrees Celsiu, adjust DO to4.5~5.5mg·L-1,decrease sludge load to0.06~0.08kgBOD5/(kgMLSS·d), increase sludge thickness to3500~4000mg·L-1and internal reflux ratio to180%, then removal rate of NH3-Nincreased from58.8%to69.7%with average effluent amount of13.9mg·L-1and theremoval rate of TN increased from12.5%to25.2%with average effluent rate of17.4mg·L-1. In the denitrifying dephosphatation test, through the analysis of phosphorusremoval rate at anoxic zone and aerobic zone, the research demonstrates thatdenitrifying dephosphatation phenomenon is indeed existed. In addition, when refluxratio is adjusted to260%, the TP effluent ratio is0.07mg·L-1and phosphorus removalrate attains92%. In the meantime, Phase I technology transformation, technology selection ofPhase II expansion, advanced treatment plan of the factory are proposed from theperspective of engineering construction. After sludge acclimatization test, the effluentratio of this factory attains Grade I Standard A of Discharge standard of pollutants formunicipal wastewater treatment plant (GB18918-2002). The research conclusion hasreference significance on the domestic urban-area sewage treatment plant which iscurrently required to upgrade grade and standard to Grade I Standard A.