摘要
采用O3／BAF和BAF／O3两种组合工艺对石化废水二级出水进行深度处理，探讨了在不同的臭氧投加量下，两种工艺对COD和NH3-N的去除效果，以及处理过程中废水中有机物分子质量分布的变化。结果表明，O3投加量为15mg／L时，O3／BAF组合工艺对COD的去除率最高为32．8％，此时进、出水COD平均浓度分别为68．82、46．22mg／L，但最高出水COD浓度〉50mg／L。而对于BAF／O3组合工艺而言，由于臭氧氧化后置，臭氧投加量越大，对COD的去除率越高，O3投加量〉20mg／L时，BAF／O3工艺对COD的去除率要高于O3／BAF工艺，在O3投加量为25mg／L时出水COD趋于稳定，且低于50mg／L。SUVA和分子质量分布结果表明，在O3／BAF工艺中O3可以对废水起到预处理作用，使大分子物质转化为小分子物质，提高废水的可生化性，从而增强BAF单元对COD的去除效果。O3／BAF共艺的臭氧投加量为20mg／L时，对NH3-N的去除效果最好，去除率为35．1％；而BAF／O3工艺对氨氮的去除与臭氧投加量的关系不大，试验过程中在12％左右。由于石化二级出水NH3-N平均在0．4～2．5mg／L之间，可达到《污水综合排放标准》（GB8978-1996）中一级标准的限值。从保障最终出水水质的要求来看，BAF／O3工艺更适用于石化二级出水的深度处理。
The O3/BAF and BAF/O3 processes were respectively used for advanced treatment of the petrochemical secondary effluent. The removal rates of COD and NH3 - N by the above two combined processes using different ozone dosages were investigated. In addition, the variation of the molecular weight distribution of the organics in the wastewater during the two treatment processes was also studied.The results showed that the best dosage of ozone in O3/BAF process was 15 mg/L. The influent COD concentration was 68.82 mg/L and the effluent COD concentration was 46.22 mg/L with the highest removal rate of 32.8% on this condition. However, the effluent COD concentration was over 50 mg/L under shock loading condition. As the post ozonation configuration for BAF/O3 process, more ozone dosage could result in more COD removal. The whole COD removal by BAF/O3 process was higher than that by O3/BAF when the ozone dosage was over 20 mg/L. The effluent COD concentration was stable and lower than 50 mg/L when the ozone dosage was 25 mg/L. The results of SUVA （UV254/DOC） and molecular weight distribution of the organics showed that ozone could transfer macromolecular organics into micromolecular organics. The biodegradability of the petrochemical secondary effluent was significantly improved by ozone, making it more suitable for the treatment by BAF. The removal rate of NH3 - N was the highest with the removal rate of 35.1% when the ozone dosage was 20 mg/L in O3/BAF process. However, the removal rate of NH3 - N fluctuated about 12% during the whole experiment for BAF/O3 , indicating that the relationship between NH3 -N removal and ozone dosage was not obvious. Considering that NH3 -N concentration in the petrochemical secondary effluent was 0.4 to 2.5 mg/L, meeting the first class criteria specified in the Integrated Wastewater Discharge Standard （GB 8978 -1996）, BAF/O3 can guarantee the effluent COD concentration to meet the standard so it is more suitable than O3/BAF for the advanced treatment of petrochemical secondary efflu
出处
《中国给水排水》
CAS
CSCD
北大核心
2015年第23期32-36,共5页
China Water & Wastewater
基金
国家水体污染控制与治理科技重大专项(2012ZX07201-005)
国家自然科学基金资助项目(51208484)
