Treating Of Simulant Leather Malodorous Gas By Trickling Biofilter

Biological deodorization method is a new technology for air pollutioncontrol, it can be divided into three directions: biological absorption, biologicalfiltration and trickling biofilte. Trickling biofilte has more advantage than theother two kinds of technology, for its high treatment effect, lower pressure, lessequipment, low cost and less secondary pollution. So it becomes one of the mostimportant way to treat malodorous gas. Leather industry takes important positionin our country, at the same time, the development of national economy make itto be one of pillar industries. However, odorous gas in the leather industry，suchas volatile NH3and H2S from ammonia nitrogen and sulfide, and other toxicmalodorous gas from decomposition and decay of solid waste endanger human’shealth and result in the pollution of environment. These factors limit it’sdevelopment. Therefore, we need to strengthen the management to malodorousgas in leather process.The study focus on odour pollution problems in leather tanning and sewagedisposal process, the treatment on stimulant leather malodorous gas containingNH3and H2S was carried out in a trickling biofililter, which was filled withhacketten and zeolite. Firstly, activated sludge was domesticated with ammonianitrogen and sulfide to optimize bacteria which could treat ammonia nitrogenand sulfide effectively. Secondly, activated sludge containing the advantagebacterium was put into trickling biofilter using the method of fast dischargingsludge to form biofilm. The reactor which was filled with hacketten and zeolitewas provided appropriate conditions to make microbe grow on the surface ofstuffing. NH3and H2S simulation leather access to the bottom of tricklingbiofilter after biofilm colonization. The gas flow, inlet concentration, packinglayer height, dissolved oxygen and pH were investigated to review the treatmenteffect of the trickling biofilter.The main research results are as follows:(1) Activated sludge was domesticated by increasing ammonia and sodiumsulfide gradually, the initial concentration of the ammoniais was14.09mg/L andremoval rate was72.05%. Removal ability of pollutants was increased with the extension of time, the removal rate of ammonia nitrogen was above95.82%during the domestication of15days, then it became flattened, it turns out themicrobial has a better ability to degradate ammonia nitrogen. At the same time, asmall amount of nitrate generation was tested. The initial concentration ofsodium sulfide is2.2mg/L, its removal rate was16.82%, after17daysdomestication, the removal rate was up to94.16%. The proportion of sulfate insulfide is increaced, and its proportion was stability22.13%at15days ofdomestication. Through the above the experimental results, it was observed thatammonia nitrogen and sulfide can be degradated by domesticated microbialeffectively.(2) Sewage sludge index (SVI) of the activated sludge was82mL/g at thebegining of domestication, then added ammonia nitrogen and sulfide graduallyinto active sludge, the SVI was rised to129.33mL/g at the10th days. Becausethe ammonia nitrogen and sulfide make the bacteria micelle condenseperformance on degradation and flocculation soluted, we found filamentousfungi increased under a microscope and the performance of the sludge decline.With the extension of time, active sludge was adapt to enhance appropriate at19days, SVI reduced to70mL/g, which shows that activated sludge maintain thegood character during the process of domestication. We observe the surface ofstuffing with electronic scanning electron microscopy after15days’s packing on,which the microbial film was attached on the surface of stuffing. It showed thatbiological membrane on stuffing surface growed well, and they could be able todeal with odorous gases effectively.(3) The experimental results demonstrated: the temperature at23.9-30.8℃,pH at6.17-7.73, humidity at34%-48%, gas flow at2L/min, NH3concentrationat16.39-80.05mg/m3and H2S at0.8-68.04mg/m3, under above condition, theremoval rate of NH3and H2S could be up to99.51%and99.82%respectively atthe stuffing height of90cm. It also met the second grade of the NationalEmission Standard for Odor Pollutants GB14554-93. The height of stuffing inthis study was45-90cm. The result showed that the removal function of odorousgases in trickling biofilter was gradually strengthened with the increase of theheight of stuffing. At the same time, trickling biofilter have already had goodprocessing effect on treating ammonia and sulphide at the height of70cm, it should be considered about other factors in practical application to set the rightpacking layer height to save energy and power.(4) Trickling biofilter treating odorous gases is a comprehensive process ofphysics, chemistry and biology. The study on the mechanism shows that NH3andH2S which dissolved in the nutrition liquid could be degraded by microbes whichadhere to the stuffing through recycling repeatedly.