Study On The Operation Effect Of SBR Process And The Co-treatment Of Municipal Wastewater And Landfill Leachate

With the rapid development of society and economy, the environmentalproblems are increasingly severe. The harmless treatment of wastewater is oneof the most effective methods for protecting the water environment. To ensurethe effluent of a wastewater treatment plant in Shanxi, which adopted the SBRprocess, achieving the Class A standard of GradeⅠ Discharge standard ofpollutants for municipal wastewater treatment plant (GB18918-2002), a fieldexperiment was carried out to study the influencing factors against the operationeffect of SBR process and the co-treatment of wastewater and surplus landfillleachate from a municipal solid waste landfill.The field experiment mainly studied the influence of different feed patternson the treatment effect of SBR process and the strengthened effect ofintermittent aeration on nitrogen removal, as well as the feasibility andoperation effect on the co-treatment of wastewater and landfill leachate.The results of the study on different feed patterns showed that without theaeration being started, the time consuming of feed-step nearly had no influence on the removal efficiency of CODcrunder instant filling and restricted-aerationfilling, both of which had consistency in degradation curves of CODcr. As aresult of the sustained low-load, the degradation rate of CODcrwas less thanthose of the other two patterns, reflected by the gentle slope on the degradationcurve of CODcrduring the filling period under non-restricted aeration mode.According to the study on dynamics, instant filling and restricted-aeration filling,along with after-filling period under the non-restricted aeration pattern,presented the characteristics of a plug-flow reactor. While the filling step underthe non-restricted aeration condition had the features of acontinuous-stirred-tank reactor. Started under a high level of substracts, thereaction rate of plug-flow reactor was fast at the beginning, but then sloweddown due to the decrease of substracts’ concentration as the reaction continued.Based on the changes in time distribution towards different steps of SBRprocess, the removal efficiency of NH3-N and TN under different aerationfrequency indicated that intermittent aeration could strengthen the nitrogenremoval in a certain range of aeration frequency. The increase of the alternatingtimes of anoxic/aerobic had less influence on denitrification but evidentlyimproved the removal efficiency of TN, which achieved the highest of80.12%with the aeration frequency as5, and decreased thereafter.During the co-treatment period, the effluent CODcr、NH3-N and TP couldmeet the standard under the proportion of1‰. As the dosage of landfill leachatebeing rasied, with the progressive increase of1‰for every7-8days from2‰ to7‰, the effluent CODcrand NH3-N rised and the effluent TP showed afluctuation change. The removal rate of the indicators presented a dowantrend.Under the proportion of8‰, the effluent indexes of SBR W, which was addedat this dosage directly, could also reach the standard but higher than those ofSBR L, while the removal rate was superior to that of SBR L as well as those ofthe proportion from1‰to7‰. Above all, the optimum proportion of landfillleachate for co-treatment is8‰, which has no impact on the operation;meanwhile meet the requirement of the solid waste landfill. Therefore, thesurplus landfill leachate from the rain-abundant time can be treated at theproportion of8‰in the wastewater treatment plant. The experiment was carriedout in summer, with the higher temperature and the lower concentration ofCODcr、NH3-N and TP from raw water, which had great effect on the results aswell.