老龄垃圾渗滤液PND-SdAD耦合工艺深度脱氮

Advanced nitrogen removal from mature landfill leachate by coupled pilot PND-SdAD process

针对老龄垃圾渗滤液具有低碳/氮比(C/N)水质特征和传统生物硝化反硝化工艺存在的高曝气能耗与碳源投加量大的问题,本研究通过构建中试规模短程硝化反硝化(partial nitrification and denitrification,PND)-硫驱动自养反硝化(sulfur-driven autotrophic denitrification,SdAD)耦合工艺,以期实现老龄垃圾渗滤液在低曝气能耗和零碳源投加条件下的深度脱氮。中试试验结果表明,PND工艺单元稳定运行阶段可对老龄垃圾渗滤液原液实现(86.0±0.8)%的总氮(total nitrogen,TN)去除效果,随后SdAD自养工艺单元可进一步去除老龄垃圾渗滤液原液(12.9±0.4)%的TN。耦合工艺出水渗滤液TN质量浓度为(38.7±4.6) mg·L^(-1),满足国家生活垃圾填埋场污染物控制标准(GB16889-2008)中TN的排放要求。同时,PND-SdAD耦合工艺出水渗滤液生物毒性降低约64.6%,毒性等级可由高毒降至低毒,有效降低了老龄垃圾渗滤液的排放风险。此外,综合运行成本分析表明,该耦合工艺垃圾渗滤液吨水综合处理成本仅为24.4元。

Aiming at the water quality characteristic of mature landfill leachate with a low carbon-to-nitrogen ratio(C/N),and the challenges faced by the conventional biological nitrification and denitrification processes such as high aeration energy consumption and large amount of carbon source dosage,a pilot-scale partial nitrification and denitrification coupled with sulfur-driven autotrophic denitrification(PND-SdAD)process was implemented to achieve advanced nitrogen removal from mature landfill leachate under the conditions of low aeration energy consumption and zero carbon source addition in this study.The results of the pilot experiment showed that the PND process could achieve a total nitrogen(TN)removal efficiency of(86.0±0.8)%from mature landfill leachate during the stabilized operation stage.Subsequently,the SdAD autotrophic process could further remove TN by(12.9%±0.4)%from the mature leachate.The TN mass concentration of leachate effluent from the coupled PND-SdAD process was only(38.7±4.6)mg·L^(−1),meeting the TN discharge standard of the pollution control standard for the domestic landfill(GB16889-2008).Meanwhile,the biological toxicity of leachate effluent from the coupled PND-SdAD process decreased by approximately 64.6%,and the toxicity level of leachate decreased from high to low,which effectively decreased the risk of leachate discharge.Moreover,based on the economic analysis,the comprehensive operating cost for advanced nitrogen removal from mature landfill leachate by this coupled process was only 24.4 RMB/m^(3).