| Activated sludge process has been become one of the widely used sewage treating technologies, because it has good treatment effect, capital cost advantages and so on, but there is one major drawback-during operation large quantities of excess sludge will be produced. From source to reduce excess sludge was the purpose of the experiment in this paper, the experiment was studied mainly from two aspects, first, o-aminophenol(OAP) can be used to reduce the production of excess sludge, but the operational performance of the activated sludge process has some negative effects, nano-magnetic particles (NMPs) have the strong adsorption capacity and catalytic properties,so in this experiment uncoupler and nano-sized magnetic particles were added simultaneously to a sequencing batch to achieve the purposes that excess sludge production can be reducd and the uncoupler had little negative impact to process performance; the second, copper ions exist in urban sewage, copper ions can inhibit the activated sludge yield, in this study, the interaction of copper ions and o-aminophenol were used to achieve the purpose of reducing excess sludge production from the source.Under simulated conditions of SBR, Nano-magnetic particles and OAP, copper ions and OAP were added to the reactor for researching NMPs and OAP’s synergistic effects, copper ions and OAP’s combined effects to the characteristics of activated sludge, process performance, sludge sedimentation performance,microbial population structure,discusses the possibility to reduce the excess sludge production from the source, by adding Nano-magnetic particles and OAP, copper ions and OAP to a sequencing batch reactor. The experiment results obtained are as follows:(1) NMPs can increase the yield of the activated sludge, enhanced removal efficiency of C, N and P, improve sedimentation performance of activated sludge; OAP can reduce excess activated sludge production, but had a greater influence on the removal of C, N, less effect of the P. In the experiment, NMPS and OAP optimal dosage is0.8g/L,15mg/L (2) During the operation for36consecutive days, it was found that the production of the excess sludge was reduced by31%with only OAP, and by25%with the combination of NMPs and OAP. At the same time, the removal of COD and P were increased8%and5%, the concentration of NH3-N in effluent and the average SVI were obviously decreased58%and10%, respectively, compared with only adding OAP.(3) After a comparative experiment for lasting36days, the activity of dehydrogenase in an experimental bioreactor was found to be increased6%than that of the control bioreactor under the synergistic action of NMPs and OAP, by using an optical microscope, it was observed that there existed diversified protozoon and metazoan in the experimental bioreactor with compact sludge floc.(4) When the concentration of copper ion in the activated sludge is lmg/L, the yield of copper ion on activated sludge was inhibited; it has the same effect as OAP to reduce the production of excess sludge. After a comparative experiment for lasting36days, it was found that the production of the excess sludge was reduced by31%,22%with only OAP, respectively, and copper ion(1mg/L), and by52%with the combination of NMPs and OAP.(5) During the operation for36consecutive days, copper ion has less negative influents on the removal of C and but has greater influents on removal of P. under the combine action of copper ions and OAP, The removal rate of COD is decreased only4%than the control with the combination of copper ions and OAP, the concentration of NH3-N in effluent was0.09mg/L(the control was0.058mg/L), little impact on the removal rate of TP early, late of TP removal rate fluctuation is bigger, but average was4%lower than the control only.(6) The sludge sedimentation performance can be improved with only copper ions, the average SVI was decreased17%and10%under the combine action of copper ions and OAP, while it was increased9%with only OAP, the results demonstrated that under the combination effect of copper ions and OAP. The activity of dehydrogenase increased13%with only OAP, decreased26%,16%with only copper ions and the combine action of copper ions and OAP, it showed that OAP and copper ions have different influences on the activity of dehydrogenase, and the influence of the OAP can reduce the negative impact of copper ions.Above results indicate that, using NMPS and uncoupler or copper ions and uncoupler to limit the sludge yield from the source in the activated sludge system was feasible. |
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