Abstract:To solve subsequent treating problems of chicken farm biogas project slurry, a research was carried out on treatment processes of anaerobically digested effluent of chicken manure for meeting the discharging standard—a case study of treatment of CSTR fermentation tank effluent of a biogas project. Based on the characteristics of anaerobically digested effluent of chicken manure, bio-chemical treatment combined with physical-chemical process was used to treat the biogas slurry. In addition, effects of three different processes combination method were investigated. First, bench scale experiment was carried out to determine the optimal operation parameters, and then pilot scale devices were introduced to examine the effect of the process. Results showed when using struvite—SBR—coagulation process treating anaerobically digested effluent of chicken manure, CODCr decreased from 9200mg/L to 280mg/L, NH+4N decreased from 3200mg/L to 36mg/L, TP decreased from 270mg/L to 3.3mg/L, finally the effluent met the standard GB 18596—2001. To remove NH+4N in chicken manure slurry, pretreatment is essential. Because of inhibition of free ammonia to microorganism, NH+4N removal rate is less than 30% while using SBR directly treating chicken manure slurry. Biodegradability of anaerobically digested effluent of chicken manure is good, but the amount of refractory CODCr is considerable. Using bio-chemical treatment combined with physical-chemical advanced process can meet the discharging standard with lower cost.