Pilot-scale test of partial nitrification-denitrification-based AO-SBR process for landfill leachate pretreatment
ZHAO Qing1,, ZHOU Hao1, LYU Hui2,3,,, ZHANG Xin4, MENG Liao5, DIAO Xingxing6 1.School of Civil Engineering, Guangzhou University, Guangzhou 510006, China 2.School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China 3.Shenzhen Research Institute of Sun Yat-Sen University, Shenzhen 518057, China 4.School of Civil and Architecture Engineering, Heilongjiang Institute of Technology, Harbin 150050, China 5.Shenzhen Xiaping Municipal Solid Waste Landfill Site, Shenzhen 518047, China 6.Shenzhen Lisai Development Co. Ltd., Shenzhen 518029, China
Abstract:When ammonia stripping is used as pretreatment process of a landfill leachate treatment plant, the problems such as poor denitrification effect, high operation cost and secondary pollution will occur. A pilot study of partial nitrification-denitrification based AO-SBR process for landfill leachate pretreatment was carried out to solve the above problems. Its nitrogen removal efficiency was investigated, the nitrogen migration and transformation path of a typical cycle in the reactor was analyzed, the final effluent water quality and operation costs of pretreatment process were also calculated. The results showed that when the influent ammonia was 1000~2500 mg·L?1, the pH of SBR tank was 6.5~7.5, DO was 1~1.5 mg·L?1, the ratio of carbon to nitrogen was adjusted to 1.4~2.0 by adding methanol, the start-up and stable operation of the partial nitrification-denitrification pilot system were realized. At the stable stage, the nitrification rate of the system reached above 90%, the removal rates of ammonia and total nitrogen were above 80% and around 50%, respectively. The nitrogen balance analysis indicated that 74.8% and 13.5% nitrogen loads were removed by the partial nitrification-denitrification and the complete nitrification-denitrification pathways, respectively. The effluent of partial nitrification-denitrification-based AO-SBR can meet the water inlet requirements of the subsequent processes, and the final water output can meet the pipe receiving standard. The main operating cost of AO-SBR was about 30% less than that of ammonia stripping process. It is technically and economically feasible to pretreat landfill leachate by partial nitrification-denitrification instead of ammonia stripping. This study provides technical support for upgrading the pretreatment process of landfill leachate treatment plant. Key words:landfill leachate pretreatment/ pilot-scale/ AO-SBR/ partial nitrification-denitrification.
图1AO-SBR示意图和现场照片 Figure1.Schematic diagram and site photo of the AO-SBR reactor
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1.School of Civil Engineering, Guangzhou University, Guangzhou 510006, China 2.School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China 3.Shenzhen Research Institute of Sun Yat-Sen University, Shenzhen 518057, China 4.School of Civil and Architecture Engineering, Heilongjiang Institute of Technology, Harbin 150050, China 5.Shenzhen Xiaping Municipal Solid Waste Landfill Site, Shenzhen 518047, China 6.Shenzhen Lisai Development Co. Ltd., Shenzhen 518029, China Received Date: 2020-04-23 Accepted Date: 2020-05-22 Available Online: 2021-02-22 Keywords:landfill leachate pretreatment/ pilot-scale/ AO-SBR/ partial nitrification-denitrification Abstract:When ammonia stripping is used as pretreatment process of a landfill leachate treatment plant, the problems such as poor denitrification effect, high operation cost and secondary pollution will occur. A pilot study of partial nitrification-denitrification based AO-SBR process for landfill leachate pretreatment was carried out to solve the above problems. Its nitrogen removal efficiency was investigated, the nitrogen migration and transformation path of a typical cycle in the reactor was analyzed, the final effluent water quality and operation costs of pretreatment process were also calculated. The results showed that when the influent ammonia was 1000~2500 mg·L?1, the pH of SBR tank was 6.5~7.5, DO was 1~1.5 mg·L?1, the ratio of carbon to nitrogen was adjusted to 1.4~2.0 by adding methanol, the start-up and stable operation of the partial nitrification-denitrification pilot system were realized. At the stable stage, the nitrification rate of the system reached above 90%, the removal rates of ammonia and total nitrogen were above 80% and around 50%, respectively. The nitrogen balance analysis indicated that 74.8% and 13.5% nitrogen loads were removed by the partial nitrification-denitrification and the complete nitrification-denitrification pathways, respectively. The effluent of partial nitrification-denitrification-based AO-SBR can meet the water inlet requirements of the subsequent processes, and the final water output can meet the pipe receiving standard. The main operating cost of AO-SBR was about 30% less than that of ammonia stripping process. It is technically and economically feasible to pretreat landfill leachate by partial nitrification-denitrification instead of ammonia stripping. This study provides technical support for upgrading the pretreatment process of landfill leachate treatment plant.