Treatment Of High Concentration Methanol Wastewater Using An Anaerobic Sequencing Batch Reactor

The primary pollutant in our country is the high concentration organic wastewater, such as methanol wastewater. At present, high concentration methanol wastewater is treated by virtue of UASB. The distribution system and solid-liquid-gas separator account for 50 percent of the total cost of UASB, which make many factories couldn't afford to build it and thus the percentage of the treatment of methanol wastewater is small. In this experiment, anaerobic batch sequencing reactor is adopted to treat high concentration methanol wastewater, which have characteridtics such as simple structure, high efficiency, saveing energy and money, running stabilization. This paper is focused on run parameters and influencing factors of ASBR pocess, and the anaerobic inhibition of methanol. wastewater as well.The results of the anaerobic inhibition experiment showed that the activity of methnogenic bacteria wouldn't be inhibited by methanol wastewater when the concentration of CODCr ranged from 3000 to 30000mg/l.Continuous experiment results showed that the system of ASBR was running normally when the system volume loading reached 9.1kgCOD/(m3.d) and CODcr removal rate was over 90%. On the contrary, when the system volume loading was declining to a very low level, the function of ASBR could not be exerted fully.In the process of operating, many influencing factors were quantified and controlled so as to obtain regularity and characters of the system. Firstly, pH was demonstrated to be the important limiting factor. The variation of pH from 6.5 to 7.0 was cracial to the stable operation of the system. Secondly, The system run at 33癈,and fluctuation of temperature would influence the system greatly. Thirdly, ALK in ASBR is low, when the system run normally, ALK of influent and effluent was between 130~450mg/l and 80~350mg/l, which illuminated that the capabilitycushioning system's acdith was weak. Finally, HRT had great influence on removal rate. When CODCrwas less than 8000mg/l, and HRT was 21h, the removal rate of ASBR reached 95%. When CODCr was between 8000~12000mg/l, and HRT was not less than 36h, the removal rate reached 90%.The direct convertion from methanol to CH4 predominated over the production of CH3COOH when the system volume loading is less than 9.1kgCOD/(m3.d). Under the opposite condition, the amount of VFA would accumulate, which made pH decline and inhibit the activity of methnogenic bacteria, reduce the removal rate.In conclusion, it is feasible and practical using an anaerobic batch reactor treats high concentration methanol wastewater.