Study On UASB Reactor For Treatment Of Swine Wastewater

The pollution of the livestock industry comes along with its rapid development, and it is on the rise over the last few years. The poultry emissions and the massive waste water haven't been proper managed and recycled but folet directly, which have become a new pollution source in our urban and rural areas. Therefore, it has already become the hot and difficult point in the present wastewater treatment field to explore economic and effective technology to treat swine wastewater.Upflow Anaerobic Sludge Blanket (UASB) process is a high-efficiency anaerobic wastewater treatment process. It has many advantages, such as less investment, less land occupation, less energy consumption and recycling resource, which fully embodies the modern environmental thought of 3R (Reduce, Recycle, Reuse).According to the characteristics of swine wastewater (urine and black soil) with high concentration of organic matters, high concentration of ammonia nitrogen and high concentration of suspended substances, we plan to adopt UASB process. The results showed:1)The start-up process of UASB reactor experienced 207 days by adopting the way of continuous water intake.The Process of granulation was described: the stage of sludge acclimation,the stage of improving loading and the stage of stable operation. The unit operated smoothly and reliably.The anaerobic granule sludge was successfully cultured and domesticated. The average removal rate of COD was 80%.2)In processes of UASB reactor, the effluent VFA was fluctuating in 200-500 mg/L.The effluent pH was fluctuating in 6.2-7.9, which was mostly in 7.1-7.8 without apparent acidification phenomenon. The average gas production rate was 056 L/L﹒d, which has the better environmental and economic benefits.3)Different COD volume load ,pH,temperature and reflux ratio, were important factors influencing the reactor performancein in different degree .The results showed that when the COD volume load was 5.64 kgCOD/(m~3·d), temperature between 30～35℃,pH=7,it can help to improve both the treatment capacity of reactor and the percentage of COD removal. Meanwhile, the reflux ratio can also help to improve the start-up process of UASB reactor.4)In the stage of stable operation, the effluent and removal rate of BOD are 145 mg/L and 90.61% respectively. The effluent and removal rate of SS are 145 mg/L and 90.12% respectively.But it has no effect on nitrogen and phosphorus removal of UASB.Therefore, it's necessary to improve the anaerobic effluent by the post-treatment process.5)In processes of UASB reactor, it can form anaerobic granular sludge of excellence subsidence performance.The most of the particle size of anaerobic granular sludge is 1-2mm,which more than 1mm is 70%.The density is 1.045g/cm~3, settlement rate is 80±10 m/h,and MLSS is35g/L. The inside of the granular sludge was black, surrounded by filamentous bacteria. Granular sludge exis stable.