| With the development of economy and the progress of the society, the stench hasbecome one of the world’s seven major public nuisance, second only to the noisepollution.Composting treatment, due to its high degree of harmlessness, minimizationand low cost, has become one of the most potential way of Municipal solid waste. butthe odor pollution problem has become the key constraints factors of waste compostingtechnology development.Among various kinds of odor control technology, biofiltrationhave many outstanding features like low cost, high efficiency, high yield and nosecondary pollution, and it has received extensive attention of all countries in the world.Biofiltration technology was chosen to remove the odor of waste composting bycomparing the existing technology, and the filters were the mixture of organic andinorganic paking. NH3and H2S, which are the typical odor in composting, were chosento be the target pollutants. The removal efficiency of gas contaminated ammoniaunderdifferent operating conditions was tested, and the efficiency of the biofilter and thechange of itsinfluence factors in steady and unsteady (reboot recovery, shock load andlow temperature) state operation was investigated. The preliminary research of thesimultaneously removal of NH3and H2S was also did. The emission of the odor fromgarbage composting and the removal efficiency of the biofilter were also investigated.the following conclusions have obtained from the experiment:①Biofiltration removing ammonia test showed thatthe reactor start-up time isabout13days, and is relatively long compared with other researchers’ results.The bestempty bed residence time is60s, the most suitable moisture content in the packingis50%-60%.②The biofilter keeps a high removal efficiency of95%-100%for inletammoniaconcentration of50-200mg/m3, In the case of temperature fluctuationsfrom20to35℃. The packing layer did not come into compaction or blocking, and the reactorcan keep stable and efficient operation.Under the condition of low temperature (7-15℃),the removal rate of basic between91%and97%for inlet concentration <100mg/m3,and the efficiency is low than the medium temperature condition, but still can achievegood removal effect.③For smaller impact load, the system can recovered removal efficiency within3hours after decrease in load, and the reactor shows strong resistance capacity to impact load. But if the shock load is too big, which can produce toxic to microbial system, it isdifficult to recover. The biofilter can recover the efficiency in72h after stops for1month,and empty load operation can reduce the recovery period.④The change of nitrogen species in filtersindicates that ammonia removalmechanism isfiller adsorption/absorption and microbial degradation.⑤The preliminary research of the simultaneously removal of NH3and H2Swas did,and NH3concentration was50mg/m3，H2Swas33.2-47.3mg/m3, and indicates highremoval efficiency of NH3(>99%)and H2S removal rate is relativelylow (92%-94%).⑥The macroscopical dynamicsofremoving NH3was evaluated based on theMichaelis-Menten model, and the two kinetic parameters were calculated withKs=26.0mg m-3，Vm=303.0g-NH3m-3d-1.⑦MSW composting experiments were conducted respectively in the environmenttemperature of22-35℃(in summer) and8-13℃(in winter). Results indicate thatNH3concentration and the compost temperature presents obvious correlation. Thehighest concentrations of NH3and H2S emitted from compostwere respectively193.2mg m-3and13.2mg m-3, and the highest concentrations of NH3emitted fromcompost in winter is smaller than in summer, were respectively102.1mg m-3and4.7mg m-3. Theremoval efficiency for the treatment of odor NH3was above97%and RE ofH2Swas100%. Result indicates that the biofilter is efficiency for the removal of odorfrom composting. |
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