Full-scale Test On The Treatment Of Landfill Leachate By The Combined Process Of Two-stage AO, Fenton Oxidation And BAF

Landfill leachate is a kind of wastewater generated by garbage in a sanitarylandfill under the effect of complex pHysical,chemical and external factors.How tomake it meet the discharge standards is a big problem in the field of environmentalprotection around the world. On current, the combined process has become theinevitable choice for the landfill leachate treatment. This paper conductedexperimental study of the combined process of two-stage AO+Fenton+BAF in severallandfills in Hunan province,explored the effect and characteristic of combination withbiological method and chemical oxidation method in the treatment of landfillleachate.The main conclusions are listed as follows:(1)Through the operation of Shimeng landfill leachate treatment plant(whichuses the combined process of two-stage AO+Fenton+BAF) and water quality, wefound that:when leachate’s influent contained997.1~1100mg-COD/L and294~295.2mg-NH3-N/L,about93.33~95.6%of COD and96.9~99.6%of NH3-N wasremoved under the condition that the dissolved oxygen is2~4mg/L in the Oxic andis less then0.5mg/L in the anaerobic of biochemical systems. The process isoperating steadily, and the water quality of outflow absolutely reaches the criterionfor normal region in “Solid Waste Landfill Pollution Control Standard”(GB16889-2008).(2) Through the operation of Xinhua landfill leachate treatment plant(which usesthe combined process of two-stage AO+Fenton+BAF)for early landfill leachate underdifferent temperature conditions, the author finds: temperature has impact on both theAO biochemical system and the Fenton reaction.In high-temperature season,biochemical system is efficient, the combined process system can operate in the highinfluent load; in low-temperature season, the effect of biochemical systems andFenton advanced oxidation system is limited, but the water quality of outflow canalso reach the criterion for normal region in the situation of low influent load.(3) The concentration of pollutants in the late landfill leachate is high, and isdifficult to purify. So the combined process of two-stage AO+Fenton+BAF should beimproved.The method is to add the polymeric ferric sulpHate(PSF) flocculationinstallation in the combined process which can reduce the concentration of effluentpollutant.The improved combined process is used in ZhiJiang landfill leachatetreatment plant, through the operation, we find the water quality of outflowabsolutely reaches the criterion for normal region in “Solid Waste Landfill PollutionControl Standard”(GB16889-2008). (4) By the analyse of technology and economy, it is sure that the combinedprocess of two-stage AO+Fenton+BAF has many advantages in efficiency, such asstability of outflow quality, high degree of automation, low cost both in constructionand processing, simple operation and easy maintenance, and it is suitable for small-scale landfill leachate treatment project.This study made comprehensive introduction and analyse on the combinedprocess of two-stage AO+Fenton+BAF. The conclusion is that the outflow throughthe combined process can meet the criterion for normal region in “Solid WasteLandfill Pollution Control Standard”(GB16889-2008).The operating characteristicsin the high and low temperature and measures to deal with late landfill leachate isalso clear, with certain significance in guiding and reference for landfill leachatetreatment engineering, and it lays foundation for two-stage AO+Fenton+BAFProcess’ popularization and application.