| This topic is based on the Ganghui sewage treatment plant, which erratically receive jeans processing waste water containing high concentration of KMnO4. Strong oxidability and poisonous effect of Mn(Ⅶ) and Mn(Ⅱ) makes the concentration of activated sludge in biological treatmen system reduced severely. The effluent quality is unstable.In order to reduce and eliminate the toxic action of biological treatment system about which jeans processing wastewater with high concentration KMnO4brought, some research were studied adopting simulation sequencing bath reactor. The MLSS was2000mg/L, COD in inflow was500mg/L, NH4+-N in inflow was23.5mg/L and inflow containing various concentrations of MnO4-or Mn2+. The research were studied as follows:the effect of KMnO4in jeans processing wastewater on biological treatment and its solve method, the degradation rule of COD and NH4+-N about wastewater containing MnO4-and Mn2+, the inhibitory action of MnO4-, Mn2+in wastewater on COD, NH4+-N dislodging and the effect of MnO4-, Mn2+on activated sludge activity and specific growth rate.Results shows that:(1) concentration of Mn2+less than10mg/L can promote the removal efficiency COD, NH4+-N and can increase the activated sludge activity within36hours before it access to activated sludge treatment system.(2) concentration of Mn2+in waste water is greater than10mg/L,4hours of aeration time can not meet the demand for removal of organic matter, when the aeration time was8hours and concentration of Mn2+below40mg/L,there had a good removal efficiency of COD and NH4+-N.(3) concentration of MnO4-(by Mn) more than20mg/L had greater inhibition ratio to removal of NH4+-N than removal of COD.(4) In processing of Activated sludge system containing MnO4wastewater, the removal rate of COD and NH4+-N were positively related to the dehydrogenase activity, respectively, and meet the exponential function respectively.(5) relative specific COD removal rate(q’/q) and relative specific NH4+-N removal rate(q’/q) have a good linear relationship with concentration MnO4-in wastewater.(6) Using E-Monod can describe the relationship between growth rate and substrate concentration more effectively when activated sludge system inhibited by MnO4-.Therefore, The actual situation for the Jun’an sewage treatment plant suggestions can be summed up as follows:(1) By increasing dosing facilities before wastewater access to biological treatment process can deoxidize Mn(Ⅶ) into Mn(Ⅱ). By dosing oxalic acid or hydrogen peroxide in wastewater can deoxidize MnO4-into Mn2+or Mn4+, Mn4+was normally excreted in the form of MnO2precipitation.(2) The concentration of the Mn2+in the wastewater was controled by installing a real-time of Mn2+monitoring devices before wastewater access to biological treatment system. when the concentration of Mn2+in the wastewater was greater than40mg/L,making use of waste water without manganese diluted wastewater before it entering the biological treatment system.(3) when the concentration of Mn2+in the wastewater is less than10mg/L, it can be access to the biological treatment system directly, but must ensure that the residence time of Mn2+in the activated sludge was no more than36hours;, process aeration time should be increased when the concentration of Mn2+was greater than10mg/L.(4) As experimental results showed:Biological treatment system can withstand the concentration of Mn2+is not greater than30mg/L of wastewater by domesticating Sewage sludge, meanwhile COD and NH4+-N effluent under standards.For other wastewater treatment plant adopted activated sludge treatment process, the recommendations as following:In actual operation, intermittent dosing Mn2+with low concentrations (less than10mg/L and exclude manganese pollution) to increase the COD removal rate, just make sure that the residence time of dosing Mn2+in the activated sludge less than36hours. If only consider the effect of NH4+-N effluent, continuous dosing divalent manganese salt with low concentrations to improve the removal rate of NH4+-N. |
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