A Research In Treatment Of Slaughterhouse Wastewater

The slaughterhouse wastewater is a kind of typical industrial wastewater with the characters:high concentration of organic matters;high concentration of ammonia and high concentration of suspended substances.If directly discharged it may have a seriously bad influence on the environment so it must be treated to meet the criterion before discharged.After collected concerned information,analyzed the sourse,the flux and the feature of the slaughterhouse wastewater and compared domestic wastewater disposal technology with the overseas,we decided to use ABR(Anaerobic Baffled Reactor)as the anaerobic treating reactor and CASS(Cyclic Activated Sludge System) as the aerobic treating reactor.As we control the influent COD at 5000mg/L,HRT (Hydraulic Retention Time) at 50h,temperature at 35℃and the ratio of Alkalinity to COD at 1:1,we get 40mgCOD/L and ammonia was 11mg/L in the effluent,also it can meet the effluent standard in China.As we want to reduce construction and operating costs,we change the conditions of ABR in the experiment:1.HRT at 50,40,30h,respectively,the efficiency of treatment ABR reactor is basically the same,and when HRT were at 20,10 h,the efficiency of treatment has a obvious decline,for the ABR-CASS system,when HRT was 50,40,30,20,10h,COD removal rate was 99%,99%,97%,89%,79%, ammonia removal rate was 88%,84%,80%,68%,44%.As we can see,when the HRT were 50,40,30 h,the system has a good efficiency of treatment.2.When temperatures was at 35℃,30℃the efficiency of treatment the reactor is basically the same,when temperature was 25℃,the treatment efficiency of reactor had a small drop,and when temperature is 20℃,15℃,COD removal rate had got a obvious decline,for the ABR-CASS system,when ABR temperature was 35℃,30℃,25℃, 20℃,15℃,COD removal rate was 99%,99%,98%,93%,79%,and ammonia removal rate was obviously the same,at around 89 percent.3.when the influent alkalinity and COD ratio was 2:1,1:1,0.5:1,0.25:1,ABR reactor COD removal rate and VFA changed little,while the pH change is obvious.For the ABR-CASS system, COD and ammonia removal rate did not change much,about 99%removal rate of COD,and 89%of ammonia can be reached.Taking into account the construction and operation costs,we recommend that of HRT for engineering is 30h,temperature 25℃, alkalinity and influent COD ratio around 0.5:1.