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The Operation Of Multi-stage Bio-chemical Process For The Landfill Leachate Treatment In Hangu Landfill Disposal Plant

Posted on:2008-05-23Degree:MasterType:Thesis
Country:ChinaCandidate:T YangFull Text:PDF
GTID:2121360245493218Subject:Environmental Engineering
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This paper relied on the analysis and operation of multi-stage bio-chemical physico-chemical process (MBP) for the landfill leachate treatment of Hangu landfill disposal plant in Tianjin Binhai New Area. This process includes multi-stage bio-chemical unit and advanced physico-chemical unit. The multi-stage bio-chemical unit includes vertical encircled oxidation ditch,biological sedimentation tank, pure oxygen intensified aeration tank, ozone catalyzed schizolysis tank and physico-chemical sedimentation tank. The advanced physico-chemical unit includes multi-medium filter, continuous micro filter(CMF) and two-stage reverse osmosis(RO).Hangu landfill leachate has the characteristics of high-salinity, high-toxity, hardly COD. The bio-chemical system has been operated from April 2006 to the middle ten-day of November 2006. During the operation, the range of COD, ammonia-nirtogen and total-phosphorous in influent were 135~28087mg/L, 37.5~5210mg/L, 0.5~15.8mg/L, respectively. The average removal efficiency of COD and ammonia-nirtogen at an overall HRT of 6d reached 92.1%, 88.8%, respectively. The vertical encircled oxidation ditch has the great contribution to the removal. Its removal of COD and ammonia-nirtogen reached 89%, 83.8%, respectively. The pure oxygen intensified aeration tank has bad results of biofilm attachment, so its removal effect is bad. The influent of the ozone catalyzed schizolysis tank is the effluent of oxygen intensified aeration tank. The suspended solids of the effluent influence the oxidation effect of the ozone catalyzed schizolysis tank to soluble organic matters. Those result in the bad performance of the two tanks. These two tanks only remove 3.1% of COD and 4.9% of ammonia-nirtogen. Because of the lacking of regulating tank, the quality and quantity of the influent results in great shock to the bio-chemical system and stable operation of system. In addition, The high-salinity of the water inhibit activity of the activated sludge badly and removal performance.The problems such as deterioration of sedimentation performance of activated sludge and foam that occurred during the operation are discussed. The problem caused mainly by several reasons: The landfill leachate has bad-biodegradable performance; The vertical encircled oxidation ditch always operates at low-loading, The activated sludge loading is 0.45 kgCOD/kgMLSS·d; The aeration intensity is high; There are a lot of filamentous fungus in the system; It has long-time anaerobic situation because of breakdown of air blower; The landfill leachate contains lots of surface active agent and hydrophobic nature matter; The long SRT of vertical encircled oxidation ditch is good for the growth of filamentous fungus. The problem can be resolved by several methods: Adding halotolerant bacteria to the system in order to inhibit growth of filamentous fungus; Adding glucose and other biodegradable matter to the system for the growth of activated sludge; Maintain the stability of the system and water quality; Reduce the mechanical failure; It can add baffle and fair water fin at the top of the tank to collect foam and lead the foam to the sludge tank in order to backfill the foam to the landfill with the sludge; At the same time ,it can also add hydraulic spray to eliminate foam.This paper also give some advice to the process problems during the operation. Suggestions: Adding regulating reservoir; improving pure oxygen intensified aeration tank and ozone catalyzed schizolysis tank. Adjusting the pipeline of the ozone catalyzed schizolysis tank and refit the oxidation pond.
Keywords/Search Tags:landfill leachate, bio-chemical reactor, oxidation ditch
PDF Full Text Request
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