一体化循环式生化反应器处理皮革废水试验研究

Experimental study on treatment of tannery wastewater by integrated circulation bioreactor

针对皮革废水含凯氏氮易使出水氨氮超标的水质特点,采用新型一体化循环式生化反应器对该废水进行生物脱氮处理试验。根据生物脱氮原理,对一体化循环式生化反应器进行了分析和设计,并研究了水中溶解氧、水力停留时间、pH值和水温对该反应器生物脱氮的影响。结果表明,水中溶解氧、水力停留时间、pH值和水温对一体化循环式生化反应器的生物脱氮有显著影响。在好氧区溶解氧质量浓度为2.5-3.0mg/L、水力停留时间为25-30h、pH值为7.0-8.0、水温为30-35℃的条件下,反应器有良好的处理效果,出水COD、凯氏氮、总氮、悬浮物、总铬和色度平均值分别为84 mg/L、6.7 mg/L、12mg/L、26mg/L、0.3 mg/L和25倍,平均去除率分别为86.8%、69.5%、53.8%、68.3%、57.1%和58.3%。

This paper is to introduce its research on the way of treating tannery wastewater by means of integrated circulation bioreactor aiming to characteristic of high content of kjeldahl nitrogen（KN） and efficient for treating tannery wastewater.In proceeding with our research,we have laid out the volume ratio of aerobic zone to anoxic zone in circulation bioreactor as 2 to 3 according to the principle of biological nitrogen removal in anoxic/aerobic process（A/O process）.Then,we have made a discussion over the effects of dissolved oxygen（DO）,hydraulic retention time（HRT）,pH value and temperature on the nitrogen removal from the tannery wastewater,as well as the effect of various dissolved oxygen in the aerobic zone on the distribution of dissolved oxygen in the anoxic zone.The results of our experimental results show that DO,HRT,pH value and temperature should all be taken as the key factors affecting the nitrogen removal from the wastewater,when the DO mass concentration in the aerobic zone is 2.5-3.0 mg/L and the HRT is 25-30 h,with the pH value of 7.0-8.0 and the temperature at 30-35 ℃,the reactor enjoys a nice biological effect on the wastewater,while the average mass concentration of chemical oxygen demand（COD）,kjeldahl nitrogen（KN）,total nitrogen（TN）,suspended substance（SS）,total chromium and chromaticity in the effluent have been worked out at 84 mg/L,6.7 mg/L,12 mg/L,26 mg/L,0.3 mg/L and 25 times,respectively.In such a condition,the average removing efficiency of COD,KN,TN,total chromium and chromaticity should be 86.8%,69.5%,53.8%,68.3%,57.1% and 58.3%,respectively.In addition,we have also found that,when the DO in aerobic zone is less than 3.0 mg/L,below 40 cm of anoxic zone is anoxic.The integrated circulating bioreactor can simultaneously go on with the carbonaceous removal,with the nitrification and denitrification in an integrated unit,the running cost could be made lower with no sludge and nitration liquid being pumped for recycling.