Experimental Study On Treatment Of High Concentration Jujube Processing Wastewater

The processing wastewater of jujube mainly includes the washing wastewater of fresh jujube and the soaking,sugar boiling wastewater and the washing water of equipment and ground during the processing of fresh jujube.The organic concentration of jujube wastewater is high.The direct discharge of jujube wastewater without treatment will cause serious environmental pollution.In this study,coagulating sedimentation-UASB-anoxic-contact oxidation process was used to treat high concentration jujube wastewater,the purification mechanism of coagulating sedimentation,UASB and anoxic-contact oxidation processes were studied in depth.The removal effect and influencing factors of each unit were analyzed.The research results can provide reference for the treatment of similar wastewater.In this experiment,coagulating sedimentation was used as a pretreatment process for high concentration jujube wastewater to remove the suspended substance and colloids in the wastewater and reduce the processing load of the subsequent treatment unit.PAC was determined as the best coagulant by small test.The optimal coagulation conditions are:at room temperature,PAC is 120mg/L,PAM is 15mg/L,pH is 7,and coagulation time is20min.The removal rate of outflow COD reached 54%and turbidity removal rate reached88%.The processing wastewater of jujube after coagulating sedimentation pretreatment was treated by UASB process.In this experiment,the high concentration jujube processing wastewater prepared in the laboratory was used as water inlet,and the simple UASB device was used as the reactor and the effects of inoculation sludge,inlet temperature,inlet pH and HRT on reactor start-up and stable operation were analyzed.The test results show that:The anaerobic pond sludge of sewage treatment plant was used as inoculation sludge.The optimal operating condition of UASB reactor is:HRT 18h,inflow water pH 9,inflow water temperature 40?.Under optimal operating conditions,the removal rate of COD from the reactor can reach 59%.Water discharge from UASB reactor was further treated by anoxic-contact oxidation process.In this experiment,anaerobic tank and aerobic tank sludge of sewage treatment plant were used as inoculation sludge respectively,domestic sewage was taken as the membrane stage to inlet water,domestic sewage and jujube processing wastewater were mixed inlet water for the domestication stage,in order to complete the reactor membrane hanging start.The changes of biofilm and biofacies during biofilm culture and domestication were observed and analyzed.The influence of different inlet COD concentration on the effluent indexes of the reactor was studied,and the effluent reflux ratio was determined.After commissioning,the system effluent COD is less than 300mg/L,NH₄⁺-N is less than 4mg/L,TP is less than 4mg/L,TN is less than 23mg/L,and effluent can achieve?wastewater quality standards for discharge to municipal sewers??GB/T31962-2015?under the ratio of jujube wastewater to backflow effluent 3:7,the optimal HRT 16h.The high concentration jujube wastewater was treated by coagulating sedimentation-UASB-anoxic-contact oxidation.The outflow was stable.The combined process has the technical feasibility and strong impact resistance,and is an effective method to treat high concentration jujube wastewater.