| Water eutrophication is becoming more and more serious in recent years, so it leadto tighten the emission standards of wastewater treatment.It is higher request to sewagetreatment plant of year-round stable operation in cold areas. My experiment is putforward optimization methods to the stable operation of all the year round in order tosolve this situation.The experiment put forward the improved A2/O process to strengthendenitrification and phosphorus removal effect for A2/O process inherent defects.Start-up two kinds process of reactors under the condition of same water qualities andyield,it is optimized with parameters such as HRT, sludge return ratio, return mixedliquid ratio,water flow distribution. Comparison of improved and conventional A2/Oprocesses on operation advantage, One of the advantage is that the removal rate ofCODSSincreased by23%, determined the advantage of the removal rate of SS underhigh content of SS. The removal rate of TP improved9%, anaerobic phosphorus releaserate and aerobic phosphorus absorption rate respectively increased by1631.3%and3%;Content of polyhydroxyalkanoates (PHA) in anaerobic zone increased to1.6mg/gMLSS, denitrifying phosphorus removal rate is increased by32.6%, from theabove aspects to determine the of advantage of phosphorus removal.According to changes in temperature throughout the year in cold district, theexperiment put forward reinforcement measures to strengthen nitrogen phosphorusremoval in low temperature.Firstly, it is studed the influnence on the activity of sludgenitrification activity and phosphorus release rate under different temperature,toinvestigate the adverse impacts on the microorganisms in these systems. Secondly, theexperiment taked three reinforcement measures of improving operatingparameters,extending aerobic HRT and adding biological bacterium when it ran at lowtemperature.It increased the sludge concentration to about4000~4500mg/L, extend theSRT to20~25d in the operation parameters improvement, the results was that theeffluent concentration of TN,TP, ammonia were respectively14.51mg/L,0.64mg/L,6.82mg/L. The reinforcement measures of extending aerobic HRT was extend theaerobic HRT for8h, the results was that the effluent concentration of TN,TP, ammoniawere respectively14.6mg/L,0.69mg/L,7.58mg/L. Finally,adding the nitrifyingbacteria of purchasing in market to strengthen nitrification effect,but treatment effectwas not stable. If it will be used in sewage plant,it needs further investigation. On the issues that it was expensive to add the methanol or acetic acid as adenitrification carbon source under low C/N ratio of sewage water quality, theexperiment put forward investigation the utilization of waste carbon source in sewagetreatment plant. The experiment has studied the feasibility of sludge dewatering liquidand hydrolyzed sludge liquid as plus carbon source. Although the content of COD insludge dewatering liquid was very high, the SCOD was less than200mg/L, so thecontent of carbon source for using was too low,that it was not as a carbon source.Inhydrolyzed sludge,the content of SCOD, polysaccharide, protein,and volatile acids(VFAs) can completely satisfy the demand of carbon source in the low C/N ratiowastewater,and it got better treatment effect with hydrolyzed sludge as carbon source.The experiment combined with the practical operation of cold area sewagetreatment plant, and inspected year-round operation of the Harbin xinyi sewagetreatment plant.The biological pool of the plant put to use modified A2/O process,whichwas same to the small scale plot process.With changes in temperature throughout theyear,it was sampled for treatment effect of the sewage treatment plant. The treatmenteffect was stable and met the emission standard requirements. |
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