Measurement of post-treatment efficiency for anaerobic digestion effluent from swine wastewater treatment

There are some difficulties to treat high concentration anaerobic digestion effluent from swine wastewater treatment plant. In this study, the treatment efficiencies of lime coagulation and anaerobic lagoon were measured. In lime treatment experiment, two doses of lime coagulation were 1 and 5g／L respectively, the sedimentation time was 1, 2, 3, 4, 5 and 6hr. In the same term, the measurements on removal efficiency of anaerobic lagoon were made at 2 times per day and (i.e., six measurement episodes) 72hr measurement episode. The result showed that average COD removal of lime coagulation treatment was 57.8% when the dose of lime was 5g／L with 5hr sedimentation time. The removal efficiency was better than 1g／L doses and anaerobic lagoon. The NH⁺₄-N removal of lime coagulation treatment was lower than the removal efficiency of anaerobic lagoon. The capital construction investment of the lime coagulation may be low because of short retention time and required volume, so it is a possible process for high concentration anaerobic digestion effluent before second grade or advanced treatment.