| With the rapid progress of urbanization and the improvement of people's living standards,the amount of municipal solid waste(MSW)increased dramatically,leading to MSW disposal facing great environmental pressure.Odor of MSW has brought a significant impact to urban environmental management and public health,thus becoming an important reason for "Not in My Yard" phenomenon.Shanghai Laogang Municipal Solid Waste disposal base is a typical representative of China's large-scale MSW disposal facilities.In 2016,more than 12,000 tons per day of MSW is treated,of which 9,000 tons were landfilled,which ranked the first place in Asia.Given the sensitiveness of its geographical location and the density of surrounding population,odor has been a big concern of Shanghai government,Pudong government and Laogang government.This problem has also become one of the main bottlenecks of sustainable development in Laogang base.However,effective odor pollution control is difficult to achieve if only being done in solid waste disposal facilities.It is necessary to study the comprehensive control strategy of odor from the perspective of whole process management.Research in this field is of great theoretical and practical significance.This paper takes Shanghai Laogang ultra-large solid waste disposal base as the research object,considereds the characteristics of the odor which are not easy to simulate and change,on the basis of the annual and spatial analysis of the monitoring data,monitoring the 9 typical odor source on the 29.5 square kilometers of Laogang solid waste disposal base,and evaluating on the biological deodorization of 6500 tons of municipal solid waste in the 5 refuse transfer stations,and studying on the odor gas collection and treatment effect by HDPE membrane and RTO.It identifys the characteristics of odorous gas in different phases and space,uses residents' interviews,and technical research and evaluation,in order to finally make comprehensive management strategies on source reduction,process suppression and final treatment.The main research work of this paper is as follows:(1)Through the historical odor monitoring data from 2006 to 2015,study the time and space changing characteristics of odor pollution in Laogang solid waste disposal base.Meanwhile,nine sampling monitoring points were set inside and outside the Laogang solid waste base.The combination of sensory analysis and material analysis was used to identify the characteristics of odorous pollution in different areas of the base.(2)Move the MSW odor control forward;and considering that Shanghai's municipal solid waste needs 1-2 days of containerized transport before entering the Laogang solid waste disposal facilities,add spraying microbial deodorant technology in the transport process;conduct comparative analysis of odor suppression effects of spraying deodorant agents for the container,the operating point of the dumping point,landfill plant boundary etc.(3)Focusing on the odor control of landfilling operation,based on the identification of odorous route and the existing control measures,this paper designed the technology of membrane gas collection and purification technology during non-operation period.On the basis of identifying the characteristics of odorous gas under the film,assess the effect of collecting odorous gas under the film and the use of regenerative combustion purification device.(4)To solve the shortcomings of lacking surrounding public perception,the GIS-based grid analysis method was used to analyze the residents' perception of the risk of MSW disposal facilities and identify sensitive and dangerous sources of the odor around the base,and then the Conditions Value Method(CVM)was adopted to assess the willingness of residents to pay for the landfill closure project to solve the odorous pollution.The main achievements of this paper include:1 Identified main odorous pollution sources and odor substances of Laogang solid waste disposal base1)Laogang solid waste disposal base has experienced changes over the years in odor monitoring points,projects,and frequency,showing the "initial concern about hydrogen sulfide,ammonia and a few inorganic pollutants,to combined inorganic pollutants analysis and sensory smell,and finally focusing on sensory sniffing".Three stages of odor monitoring all had indicators exceeding standards,especially in 2014 and 2015.With monitoring points and frequency increasing,the odor pollution became more seriously,of which Phase 4 and 5 landfills and the leachate plant are the main sources.(2)The monitoring results of the five online monitoring inside and outside Laogang solid waste disposal base show that the odourous pollution in the site of manage building and western boundary are more serious than others.The odourous pollution often occurs between April and October,consistenting with the records of the surrounding residents' committee.Through the correlation analysis,the odor concentration and temperature have a medium correlation(r=0.446).This conlusion indicates that the odour control is important from the July to October.(3)The monitoring results of nine sampling points inside and outside Laogang solid waste disposal base show that the odor concentration of the exhaust gas in the waste cover area is the highest(6500);the odor of the sludge transshipment terminal,the container transshipment terminal,and landfill operation site were all exceeding 300.Ammonia is the most important contributor to the total material concentration of all sampling points-the average concentration is 3254.7 ppb,and the contribution rate of the total material component is more than 83.6%.Considering the effect of odor on human's smell,the highest contribution source of odor is sulfide,the average odor concentration(TOC)contribution rate is 79.3%,ammonia followed.Eleven kinds of odorous substances,such as acrolein,methyl sulfide,ammonia,ethylbenzene,inter--xylene,etc.,are the priority control substances in the working surface of the landfill site.This conclusion shows that the microbial deodorant has obvious effect on sulfur compounds.2 Identify deodorant effect of odor inhibition process and end control(1)Spraying deodorant in the container during collection and transportation process has a certain effect for reducing terminal odor pollution.After 12-24 hours of containerized transportation,odor concentration in the container with spraying microbial deodorant was significantly reduced.The landfill operating surface and the field also showed odor reduction to some extent.After forty-eight hours,the concentrations of four kinds of compounds,such as methyl mercaptan,methyl sulfide,toluene,ethyl acetate decreased significantly in the in the Xupu waste containers,and the concentrations of five kinds of compounds,such as methyl mercaptan,methyl sulfide,dimethyl sulfide,sulfur dioxide,ammonia nitrogen,toluene,decreased significantly.It indicates that this microbial deodorant has a significant effect on sulfur compounds.(2)Use "tube collection under the film + regenerative purification" odorous gas collection and treatment method on the landfill operating surface,can solve the problem of simultaneously releasing odor with high concentration.During the non-operation period,the odor gas collected by the film is regenerated by regenerative combustion.odor remove rate can achieve more than 92%and drop H2S,TVOCs and odor concentration by 75-90%.3 Quantify the public's willingness to pay for odor risk perception and environmental improvement in Laogang base(1)The public around Laogang base significantly affected by the odor.The public's concern about the odor is more intense than other problems such as leachate.Perception of the odor in the surrounding area of 3km is the most obvious and decreases with the distance.The effect of the odor at 9km was relatively small,the highest frequency of odor mainly occurred in the southeast area during summer.(2)About 51.76%the population were willing to pay for the project;the average of willingness to pay(WTP)is 56.06 RMB/month.Those unwilling to pay generally think that odor pollution control has nothing to do with the individual and the government should be solely responsible.Whether the respondents are willing to support was significantly positive related with monthly income and project support.4.Raised a comprehensive management strategy for odorous pollution,which aims at source reduction,process suppression and end control(1)Limiting degradable MSW to enter the landfill is an effective way to control the odor.The classification of MSW in Laogang base should be strengthened from the aspects of reorganization of administrative,social and market management systems and improvement of the technologies(composting and anaerobic digestion).(2)Spraying biological deodorant can effectively reduce odor problem during MSW collection and transportation process;by automatically transforming the transport stations,or by controlling amount and dilution ratio of microbial deodorant in different seasons and different processing capacity and to achieve intelligent regulation for the odor.(3)Use internal integrated prevention and control as well as external public feedback network combined to strengthen odor pollution management for the base.By strengthening risk communication and science popularization with the surrounding public,we will build a base system of odor monitoring network with dynamic monitoring and real-time response,and establish an emergency warning system for odorous pollution,and finally realize the active prevention and control for Laogang base. |
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