| Corn starch comprehensive processing wastewater is a kind of high-concentration organic wastewater which is difficult to treat.Its composition is complex and the content of organic matter is high.The wastewater is mostly anaerobic and aerobic multi-stage treatment process,and the focus of current attentionits is sewage treatment process runs efficiently and economically.Hei long jiang Corn Starch Processing corporation is a corn deep processing enterprise that produces corn starch,dextrin and lysine.The production wastewater of the enterprise adopts IC anaerobic and A/O combined sewage treatment process,which is a conventional treatment method of corn starch wastewater comprehensive processing,but the treatment process is constructed earlier,the operation time is long,and the production wastewater of the enterprise changes,the wastewater treatment process has a poor effect.Through one month of on-site operation and experimental determination,this paper analyzes the purification effect of COD and ammonia nitrogen under different operating conditions of IC anaerobic and A/O process,and determines the optimal operation control technical parameters of the whole process.The current operating status of the wastewater treatment plant was studied:the volumetric load of the IC anaerobic reactor was about 6.21 kg(COD)/(m~3·d),the hydraulic retention time was about 10 h,the rising flow rate was 1.55 m/h,and the COD removal rate was 89%.Left and right;A/O process influent pH is 6.3~7.5,reflux ratio is 210%,aerobic tank DO is 2.5~3,COD removal rate is 85%,ammonia nitrogen removal rate is 92%,total nitrogen removal rate is 80%.There is an IC process that does not reach optimal operation,and the total effluent total nitrogen is above 25mg/L,and the concentration is relatively high,due to high aerobic pool DO and high reflux.At the same time,the optimization of IC anaerobic reactor was carried out.HRT increased from 10 h to 11 h,and the volumetric load decreased from 6.21 kg(COD)/(m~3·d)to 5.89 kg(COD)/(m~3·d).From 1.55 m/h to 1.45 m/h,the COD removal rate increased from 80%to 91%.As well as optimization research of A/O process,the reflux ratio of the mixture was reduced from 210%to 150%,the DO of the aerobic pool was reduced from 2.5 to 1.8,the COD removal rate was basically 82%,and the COD removal rate was increased from 83%to 84%.The ammonia nitrogen removal rate increased from 92%to 96%,and the total nitrogen removal rate increased from80%to 84%.The optimal operating state of the IC anaerobic reactor is obtained:when the HRT is 11 h,the volume load is 5.89 kg(COD)/(m~3·d),and the rising flow rate is 1.45 m/h,the effluent COD is basically below 300 mg/L.The COD removal rate reached 91%.By controlling the influent flow rate to 91m~3/h,the operating state of the IC anaerobic reactor can be optimized to improve the COD removal effect.Optimal operating state of A/O process:reflux ratio is 180%,aerobic pool DO is about 2.0,COD removal rate can reach 84%,effluent COD concentration can reach below 50mg/L,ammonia nitrogen removal rate is about 93%,effluent The ammonia nitrogen concentration is below 10 mg/L,the total nitrogen removal rate is 84%,and the total effluent nitrogen is less than 20 mg/L.A/O process aerobic tank DO is high,reflux increases the anaerobic tank DO to affect the denitrification reaction,reduces the aerobic tank aeration time to make DO reach 2.0,and reduces the mixture reflux ratio to 180%,the total nitrogen removal rate Increase by 3%,the total nitrogen in the effluent can be reduced to below20mg/L. |
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