Study On Treatment Of Domestic Animal Breeding Wastewater By Anaerobic Sequencing Batch Reactor

A study was carried out to assess the efficiencies of anaerobic sequencing batch reactor to treat animal breeding wastewater. The main objective of the study was to assess the effect on a pilot scale reactor, while studying the behavior of the system at different organic and hydraulic loading rates. The results of the study show that:(1) After more than 70 days, the final organic loading was 7.5 kgCOD/(m~3·d). The average COD and BOD5 removal efficiency were respectively 80.91% and 93.72% when the organic loading was between 5 and 7.5kgCOD/(m~3·d). In the normal runtime of ASBR, the rate of methane output was between 1.0 and 2.1m~3/(m~3·d), the maximal rate of one-day output can be reached to 2.8m~3/(m~3·d).(2) With the gradual rising of the OLR of influent, the SS of effluent was increased. But it was mostly under 800mg/L, and the average removal efficiency was 78.34%. When the OLR was between 5 and 7.5kgCOD/( m~3·d), the SS removal was lower. Delaying the sedimentation time can make for improving SS removal efficiency.(3) The VFA of effluent was fluctuated between 200 and 500mg/L during the experimental process. On the 38th day, the VFA of effluent was reached to 1100 mg/L due to the OLR over increase. After adding NaHCO3 properly, the VFA of effluent was gradually reduced to 400mg/L. With the rising of OLR, the pH of effluent also declined. But after few days, it can be stabilized mostly without obvious acidification.(4) A treatment cycle of ASBR can be divided into two parts. In the first parts, an increase in the concentration of VFA was observed. Concentration of VFA peak at the end of the first phase, decreasing regularly thereafter during the second phase at a constant rate. SCOD concentration decreased at a lower rate in the second part compared to the first.(5) A dynamic model for microbiological process occurring within an ASBR has been developed and experimentally validated for a animal breeding wastewater-fed ASBR. The model simulation indicated that increasing fill-cycle length for a giving total cycle time improved VFA removal for one cycle. The sequencing batch mode of ASBR can achieve the goal of separating SS from the wastewater. The reactor is fit for treating the wastewater that including higher SS concentration.