The Anatomy Of MSW Odor Sources And Reducation Of Odor Emission At Source

MSW was an important source for odor emissions, and the MSW generation rate increased greatly due to the rapid urbanization process and the special living habits of the local citizens. Odor emissions were the main cause from the local resident complaints, since a short distance was often observed between the MSW facilities, such as the rubbish bins, the waste transfer stations, vehicles and the local resident communities. Moreover, the complexity of odorous components and concentration, non-uniform of determined methodology and evaluation methodology resulted in the poor performance of odor control. In this work, the odor emission processes from MSW was investigated, and the main odor components were identified and screened from the different degradation stage of MSW. Odorants from different waste disposal facilities, i.e. Laogang Refuse landfill, Guoqing composting plant, and Xupu transfer station, were sampling and compared. Besides, the odor concentration of these disposal facilities were tested and compared. Some inhibiditors were chosen for the odor emission control from the MSW by the reduction of the MSW degradation process. The detailed conclusions were show as bellows:(1) Odor concentration from the simulated lysimeters were around 3000 and 6000 after the 5 operation days under the anaerobic and aerobic condiction, respectively, while H2 S and NH3 in anaerobic condition were lower than that in aerobic condition. H2 S was found to released from day 5 to day 10, and NH3 was released from day 10 to day 20. The VOCs(volatile organic compounds) in biogas were mainly Alkanes, Aromatics, Oxgyenated compounds, Chlorobenzene and sulfide. The concentration of total volatile organic compounds(TVOCs) was rising from the startup to the ninth day, and then declined, with the highest concentration of 3600 mg/m3 in anaerobic condiction and 2000 mg/m3 in aerobic condiction. According to the TOC method(theory odor concentration), Sulfide, Oxygenated compounds and Aromatics were the main components of VOCs.(2) As the biggest transfer station,Xupu tansfer station could treated 3500 ton MSW per day, and 92 species odorants were founded here, including H2 S, NH3, alkanes, aromatics, oxygenated compounds, halogenated compounds and CS2. The concentration of NH3 was the higest one(1334~3802 ppb), followed by Alkanes(131~224 ppb), Oxygenated compounds(10~100ppb) and H2S(15~40 ppb). The concentrations of others were all less than 1 ppb. A list including 20 species of odour pollutant for priority control has been advanced, i.e. H2 S, toluene, NH3, ethyl benzene, o-xylene, dichloromethane, propane, benzene, m,p-xylene, cyclohexane, carbon disulfide, acetone, butane, heptane, 3-methylhexane, acetic ether, ethane, butanone, methyl isobutyl ketone, styrene.(3) The odor concentrations of all 9 sampling points in Laogang landfill were greater than 3500(non-dimensional), and the average concentrations of H2 S and NH3 were 0.24 mg/m3 and 0.34 mg/m3, respectively. The percentages of total chemical concentrations of individual odor families were 34%(Oxygenated compounds), 30%(Alkanes), 16%(sulfide), 11.4%(Aromatics), and 1%(others). Sulfide and Oxygenated compounds were the main contributors to the odor concentration due to their low threshold concentrations.(4) The average odor concentration was 6062 in Guoqing composting plant of MSW. The chemical concentration of NH3 was lower than the limited concentration under Chinese Nation Standards for emission of odor pollutants(GB14554-93). And H2 S was only determined in the FWDP(Fresh waste dumping pool). Sulfide and Oxygenated compounds were also the main contributors, which took 40%and 44% of the total odor concentration, respectively.(6) The inhibitors of sodium benzoate, sodium sorbate, dehydroacetic acid, Nipaqin esters, sodium nitrate, natamycin were selected to reduce the biodegradation process of the MSW, and solium nitrate and natamycin were the two best inhibitors for the MSW degradation during the the early stage of waste degradation. S1 and N1 have good performance for the odor control after 160 hours under the test conditions.