响应面法优化负压原位碱度脱氨处理垃圾焚烧厂渗滤液AnMBR出水

Optimization of vacuum in-situ alkalinity ammonia removal from the effluent of AnMBR treating the incineration leachate by response surface methodology

针对垃圾焚烧厂渗滤液厌氧膜生物反应器(anaerobic membrane bioreactor,AnMBR)出水中仍含有高浓度氨氮,无法满足现行排放标准的问题,采用负压原位碱度脱氨工艺对AnMBR出水进行进一步处理;考察了温度、真空度和脱氨时间3个因素对负压原位碱度脱氨工艺氨氮去除率的单独作用,分析了不加碱前提下脱氨过程中体系pH的变化,并利用响应面学的方法对3因素的交互作用进行了探讨和分析。单因素实验结果表明:各因素在响应范围内对氨氮的去除有显著性影响,在温度为60℃、真空度为−0.08 MPa、脱氨时间为2 h时,氨氮去除率达到75.5%;在负压原位碱度脱氨过程中,AnMBR出水中自有碱度对pH具有显著调控作用,碳酸氢根水解致使反应体系pH上升进而促进氨氮脱除;利用响应面法探讨了各因素对氨氮去除率的影响,其对于氨氮去除率的贡献排序为温度>真空度>脱氨时间;确定负压原位碱度脱氨的最佳时间为3.5 h,温度为59℃,真空度为−0.079 MPa,该条件下氨氮去除率为92%以上,并对该模型进行了实验验证;响应面法的预测值与实验值吻合较好。由此可知,通过负压原位碱度脱氨可以去除垃圾焚烧厂渗滤液AnMBR出水中大部分氨氮,并大幅提高C/N比,为后续与适当的生化处理工艺组合处理奠定了良好基础。该研究结果可为负压原位碱度脱氨法处理垃圾焚烧厂渗滤液AnMBR出水中氨氮的工业化应用提供参考。

Generally,the quality of anaerobic membrane bioreactor(AnMBR)effluent from incineration leachate cannot meet the discharge standard due to the high concentration of ammonia nitrogen.In this study,vacuum in-situ alkalinity ammonia removal process was used to conduct the advanced treatment of AnMBR effluent.The respective effect of temperature,vacuum degree or time on ammonia nitrogen removal rate was investigated.Then the change in pH in the system without adding alkalinity was analyzed during the ammonia removal process.Furthermore,the interaction of three factors was discussed and analyzed by response surface methodology(RSM).The results of single factor experiment showed that each factor presented a significant effect on ammonia nitrogen removal rate.At 60℃,the vacuum degree of−0.08 MPa,and the deamination time of 2 h,the ammonia nitrogen removal rate reached 75.5%.The own alkalinity in AnMBR effluent had a significant regulation effect on pH during the vacuum in-situ alkalinity ammonia removal process.Bicarbonate in the AnMBR effluent hydrolyzed under the conditions of vacuum and heating,and the produced carbon dioxide volatilized from the system.This process could lead to a pH increase and promote ammonia nitrogen removal.In addition,the effects of temperature,vacuum degree and time on ammonia nitrogen removal rate were investigated by RSM.The order of contribution of three factors to ammonia nitrogen removal rate was as follows:temperature>vacuum degree>time.Under the optimum conditions as follows:time of 3.5 h,temperature of 59℃and vacuum degree of−0.079 MPa,the ammonia nitrogen removal rate was over 92%.Then the model was further verified by experiments.The results showed that the predicted values were in agreement with the experimental values.Therefore,most of ammonia nitrogen in AnMBR effluent could be removed by vacuum in-situ alkalinity ammonia removal process,and the C/N ratio of the incineration leachate increased substantially.The results of this study can provide a reference for the industrial application of vacuum in-situ alkalinity ammonia removal process treating the AnMBR effluent from incineration leachate.