The Test Research Of Coke Plant Wastewater Biological Treatment By The A₁ And A₂ Stage Of A₁-A₂-O-M Process

Taking the coke plant wastewater as the study subject, the activated sludge was fostered and tamed for the A₁ and A2 reactor of anaerobic-anoxic-aerobic-fixed biofilm Process firstly , the task researched the biodegradation property of microbe to COD and NH₄⁺ -N in the A1 and A2 reactor and how environment element effected the biodegradation process. Based on the test, the optimum process conditions and operating parameters were summarized for the A1 and A2 reactor. In combination of the O and M stage of A1-A2-O-M process, the average effluent concentration for COD and ammonia nitrogen was less than 150mg/L and 15mg/L each, the two indices of which had attained the secondary and primarynational standard about wastewater discharge standard ?GB8978-1996? respectively.Based on the analysis of the experiment result, the optimum operating parameters were summarized for the A1 as follows: the pH value of the anaerobic reactor was maintained at 6.5⁷.5, The hydraulic retention time was 9 hours, the temperature was maintained at 28.0³2.0,the influent COD was 1100mg/L,and DO should less than 0.5 mg/L.The optimum operating parameters were summarized for the A2 as follows: the pH value was maintained at 7.0-7.5, The hydraulic retention time was 10 hours, the temperature was maintained at 25.0-30.0 ,the influent COD was 800 1100mg/L,DO should less than 1.0 mg/L.The experiment result also indicated that anaerobic hydrolytic pretreatment raise the biodegradability of coke plant wastewater greatly , and that the ratio of BOD5/COD'was raised from 0.348 to 0.440. Anaerobic hydrolytic acidification could buffer effect of influent load,and alleviated the inhibition of the poisonous and difficult degradation material to microbe ,and offered the betterinfluent condition for follow-up reactor. Anaerobic hydrolytic reactor also could change the chemical formation and characteristic of organic compound for coke plant wastewater, and offered the carbonaceous organic material degraded easily for denitrifying bacteria , and converted the organic nitrogen into NH3 - N ,and raised the denitrification effect. The test used the glucose and coke plant wastewater as the carbon source. The result demonstrated that the denitrifying effect was good yet,and the removal rate of COD in the A2 reactor and system was not changed clearly,when the carbon source was not thrown into the A? reactor.