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微氧活性污泥-Fenton-AF-BAF组合工艺对垃圾渗滤液处理的研究

Limited Oxygen Activated Sludge Cooperated with Fenton-Anaerobic Filter-Biological Aerated Filter for Treating Landfill Leachate

【作者】 陈志伟

【导师】 汪晓军;

【作者基本信息】 华南理工大学 , 环境工程, 2011, 硕士

【摘要】 根据杭州天子岭垃圾填埋场垃圾渗滤液有机成分复杂、氮含量高、毒性大、可生化性差等特点,采用“微氧活性污泥/两级Fenton-AF-BAF”组合工艺处理垃圾渗滤液。微氧活性污泥以短程硝化-反硝化为理论基础,通过对溶解氧的控制来实现短程硝化反硝化。其中1#生化池DO在0.1mg/L左右,2#生化池DO在1 mg/L左右,3#生化池DO在0.5 mg/L左右,4#生化池DO在0.1mg/L左右,形成缺氧/兼氧/兼氧/缺氧工艺。通过出水和污泥回流稀释进水的氨氮和有机物浓度和增加反应器中的MLSS,以增强处理能力和抗冲能力,形成了高效的脱除有机污染物、NH3-N和TN的系统,其对COD、NH3-N和TN的平均去除率分别达到90%、99.8%和90%。C/N比是短程硝化-反硝化反应非常重要的影响因素之一,它是NO2--N和NH3-N转化为N2的重要限制因素之一。C/N≥4时能取得较好的短程硝化-反硝化效果。微氧活性污泥出水仍含有一部分总氮和难生物降解的有机物,采用两级Fenton-AF-BAF深度处理组合工艺进行处理。Fenton氧化反应能有效去除废水中难以生物降解的有机物,在提高废水可生化性的同时很好的降低色度。Fenton氧化反应的小试结果表明,Fenton氧化反应处理微氧活性污泥出水的最佳条件是:H2O2/COD=1.5,n(Fe2+) / n(H2O2)投配比为1,初始pH值=4,反应时间为2 h,则能把废水COD从740 mg/L降到240 mg/L,COD去除率达到68%。根据随着某一反应条件的变化,COD的去除率变化范围可知,n(Fe2+) / n(H2O2)投配比和废水初始pH值,对处理效果影响最大,H2O2/COD次之,反应时间影响相对最小。经Fenton氧化后,通过补充碳源甲醇,使废水C/N在3-5之间,AF-BAF反应器通过硝化-反硝化反应去除废水中的总氮和有机物,使出水满足《生活垃圾填埋场污染控制标准GB16887-2008》规定的相关标准。

【Abstract】 Landfill leachate in Hangzhou Tianziling landfill contains complicated organic component, high nitrogen, so the wastewater is high toxic and hard to biodegrade. According to the characteristic of the landfill leachate, limited oxygen activated sludge cooperated with the two stage Fenton -anaerobic filter (AF)- biological aerated filter(BAF) processes were applied.The theoretical principle of limited oxygen activated sludge is short-cut nitrification and denitrification. The DO value of the bioreactor is the main control method to achieve short-cut nitrification and denitrification reaction. The DO values of 1#, 2#, 3#, 4# bioreactor were about 0.1 mg/L, 1 mg/L, 0.5 mg/L, 0.1 mg/L respectively basing on the pilot plant study. The measure made the four bioreactors into the anaerobic/ facultative/ facultative/ anaerobic bioreactor. In order to strengthen the treating capacity and anti impact load, the effluent and sludge of bioreactor were backflowed to dilute pollutant concentration and increase mixed liquor suspended solid(MLSS). It helped to form high efficient organic, ammonia nitrogen and total nitrogen treatment process. Therefore, the average COD, ammonia nitrogen and total nitrogen removal rate reached 90%、99.8% and 90% separately. The C/N ratio was one of very important influencing factors in short-cut nitrification and denitrification. And it was significant restricting factor of nitrate nitrogen and nitrite nitrogen transforming into nitrogen. It was able to achieve favorable result in the condition of C/N ratio≥4.Because the effluent of limited oxygen activated sludge still contained a portion of total nitrogen and refractory organic, the two stage Fenton-AF-BAF advanced treatment process was applied. Fenton oxidative reaction was capable of removing refractory organic and colour in wastewater effectively. The experimental result showed that the optimal operational condition of Fenton oxidative reaction treating effluent of limited oxygen activated sludge was: H2O2/COD= 1.5, n(Fe2+) / n(H2O2)= 1, the initial pH of wastewater= 4, the retention time= 2 h. In the condition, the COD declined from 740 mg/L to 240 mg/L and the COD removal rate was 68%. In the light of the varieties of the reaction condition and COD removal rate, n(Fe2+) / n(H2O2) ratio and the initial pH of wastewater were the most significant factor of treatment effect. H2O2/COD ratio took the second place. And the retention time was the least important factor.And then increase C/N ratio to 3-5 through adding carbon source methanol. Through nitrification- denitrification reaction, AF- BAF process could remove total nitrogen and organic in wastewater. And it made the effluent meet the the requirement of national landfill leachate discharge standard (GB-16889-2008).

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