| Eutrophication caused by phosphorus pollution has caused serious harm to the livingenvironment of mankind, and become one of the most important issues of the waterenvironment. Urban sewage is the main source of phosphorus of water body, and controllingof phosphorus emission of urban sewage has become an important way to solve the problemof eutrophication. The traditional biological phosphorus removal process faces so manyproblems in treatment of low COD/N sewage that the development and application of newbiological phosphorus removal process is very necessary.The experiment selected ABR&biological contact oxidation process as treatmentmeasure. On the basis of summing up the results of previous studies, the performance ofphosphorus removal of ABR&biological contact oxidation process was researched with lowCOD/N artificial sewage as object. The experiment content included the study on the startupof the reactor, the optimization of operating parameters, the analysis of performance andmechanism of phosphorus removal and so on. The experiment results showed that:(1) ABR&biocontact oxidation process organically combines with the ABR process andbiocontact oxidation process. Compared to the traditional A/O process, it effectively improvesthe utilization of carbon sources and strengthens the performance of phosphorus removal withhigh removal rates of COD and TN.(2) The influence factor of starting up of ABR-biological contact oxidation reactorincludes COD/TP, SS, pH, DO, SRT and so on. The reactor started up with low andcontinuous influent load, in which the condition is that the COD/TP≈30, pH=6.5~8.0, theDO of ABR section≈0.5mg/L, the DO of aerobic section≈2.0mg/L, SRT≈10d. HRT wasgradually reduced to increase the influent load so that startup period could be shortened andthe startup period lasted for32d. In the end of startup period, the removal rate of CODreached90%, the removal rate of TP reached55.7%and the removal rate of TN reached56.1%.(3) When the HRT ranged from4to12h, the removal rate of TP increased and thendecreased as HRT increased. When HRT was8h, the removal rate of TP reached the topwhich was62.8%with the effluent TP concentration of3.5mg/L. When the reflux ratioranged from1to3.5, the removal rate of TP increased and then decreased as reflux ratio increased. When the reflux ratio was2.5, the removal rate of TP reached the top which was82.5%with the effluent TP concentration of1.8mg/L. When the temperature ranged from15to30℃, the removal rate of TP happened a tiny change as temperature increased. The averageremoval rate of TP was82.1%with the average effluent TP concentration of1.8mg/L. Whenthe HRT was8h, the reflux ratio was2.5and the temperature was30℃, the phosphorusremoval of the reactor showed the satisfactory performance, while the system also achievedoptimal deployment of carbon source.(4) When the COD/N≈5and TP≈10mg/L, under the best operating conditions of thereactor, the average removal rate of TP reached83.0%, better than traditional A/O process,with the average effluent TP concentration of1.7mg/L. Besides, the average of COD removalrate was95.4%with the average effluent COD concentration of13.9mg/L. The averageremoval rate of TN was74.8%, with the average effluent TN concentration of15.3mg/L.The removal rate of NH+4-N was90.2%with the average effluent NH+4-N concentration of5.8mg/L. The contentration of COD, TN and NH+4-N of the effluent meet the first B standard ofDischarge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB18918-2002).(5) When the COD/N of the influent ranged from5to10, the average removal rate of TPincreased as the COD/N increased slowly. When the COD/N was about10, the removal rateof TP reached91.1%with the effluent TP concentration of less than1.0mg/L which meet thefirst B standard. When the COD/N of the influent was less than5, the average removal rate ofTP increased as the COD/N declined because of strengthening of denitrifying phosphorusremoval. |
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