城市生活排水系统废气产排污系数核算研究

发布时间：2018-07-12 12:07

本文选题：排水系统 + 废气　；参考：《昆明理工大学》2013年博士论文

【摘要】：城市生活排水系统主要由化粪池、输送管道、各类检查井、泵站和污水处理厂等单元组成,是城市的一项基础设施,为城市的正常运转提供了重要支撑。它作为城市生活污水收集、输送和处理系统的同时,也成为一个巨大的生化反应系统,其间产生的CH4、H2S等废气一直威胁着市政工人的正常作业和生命,影响着城市居民生活和健康。这些有毒、有害气体的监测和控制已引起政府和公众的关注。国外在这方面的研究工作起步较早,国内则对污水处理厂废气的研究较多,而对收集和输送系统废气的研究很少,尤其是产排污系数方面的研究尚属空白。本论文以昆明城市生活污水排放系统中化粪池和各种检查井废气产生与排放为主要研究对象,结合课题组提供的广州、兰州城市生活排水系统废气产排放系数,开展了以下研究工作： (1)在文献调研、专家咨询和初步实测的基础上,确定城市生活排水系统废气的特征污染因子,通过开展城市生活排水系统废气产生、排放规律研究,系统分析城市生活污水排放系统废气的组成及其影响因素； (2)通过实验室模拟研究,获取分功能区城市生活污水在不同条件下的污染物降解和废气产生量数据,采用模型分析工具软件等手段,研究其动力学规律； (3)采用现场实测与实验室模拟相结合的研究方法,初步建立基于可获取统计量(如居民人口、生活污水排水量、城市生活排水管线长度或单位污染负荷等)的城市生活排水系统废气产排放系数,构建特征废气排放量核算方法,初步估算主要废气污染指标的排放量。通过对昆明城市生活污水排水系统现场实测和开展模拟实验,研究排水系统废气产生、排放规律,测算城市生活污水排水系统中特征废气的产排污量,主要得出以下结论： (1)特征废气的产排具有时段性,体现在一天之内的用水高峰时段和低峰时段,也体现在一周之内工作日和非工作日的区别：在用水高峰时段,各种特征废气的产排量要明显高于用水低峰时段；降雨对合流制排水系统中特征废气的产排具有较大影响,而对分流制排水系统无影响；排水系统中跌水井内因污水紊流程度较高,有利于废气从液相到气相的扩散,导致排水系统中废气的产排量增大。 (2)城市生活排水系统的废气产生与排放单元主要集中在化粪池和各种检查井,尤以化粪池的产生和排放占主要比例,一般在检查井(包括沉沙井、沉泥井和跌水井等)中只能监测到H2S和C02气体,而化粪池能监测到H2S、CO2和CH4,化粪池和检查井相比,其厌氧程度要高,化粪池中C02浓度高于检查井,这是因为污水在化粪池停留时间一般为12-24h,停留时间长有利于污水有机物的厌氧降解反应和提高废气累积量,化粪池底部由于长期淤积,会沉积大量的底泥,有利于CH4气体的产生。 (3)各个功能区由于水质水量不同导致各区排水系统特征废气的产排有所差异,餐饮区污水中COD浓度要明显高于其他三个功能区,餐饮区H2S和C02气体的排放速率要高于居民区。 (4)通过模拟实验得出影响生活污水在排水系统中生化反应产气的主要因素有水力停留时间(Hydraulic Retention Time, HRT)、有机物浓度、pH值和水温；影响其排放进入城市大气环境的主要因素则是水力湍流程度；排水体制对废气的产排影响主要体现在合流制排水系统在雨季时因管道充满度的增大而使气体排放量增大。 (5)根据居民生活污水模拟实验结果,得出污水中COD降解和CH4产量之间的关系,并用一级动力学方程获得底物的降解系数常数为KH=0.0164h-1,拟合方程为-1n(X0/Xt)=0.0164t-0.21；pH为6.9时,CH4的最终浓度最大为5.80g/m3；温度为25℃时,居民生活污水CH4的最终浓度9.18g/m3。 (6)对比研究城市生活污水排水系统CH4的产排系数与IPCC清单指南中的建议值可以发现,由IPCC指南提供的CH4的最大产生系数为0.25gCH4/gCOD,化粪池CH4排污系数为0.125gCH4/gCOD。此产污系数是兰州产污系数的3.6倍,排污系数是兰州产污系数的10.7倍；IPCC提供的CH4排污系数是昆明化粪池排污系数的43倍,是广州化粪池排污系数的33倍。估算昆明市排水系统中2011年产生的H2S气体产生量为7.96t/a,排放量为1.46t/a,排放率为18.30%,CH4气体产生量为109.52t/a,排放量为44.63t/a,排放率为40.74%,C02气体产生量为957.69t/a,排放量为300.13t/a,排放率为31.00%。本论文的研究成果不仅提供了昆明市城市生活排水系统废气的产排污系数,而且实证了IPCC清单指南中给出的城市废水处理CH4排放系数建议值偏大,为城市温室气体核算提供了基础数据,具有重要意义。本论文部分研究成果已经在昆明市排水系统管理中得到了应用,对国内其他城市生活污水排水系统废气产排污系数核算研究和废气控制具有较好的指导和借鉴意义。
[Abstract]:Urban living drainage system is mainly composed of septic tank, pipeline, all kinds of inspection wells, pumping stations and sewage treatment plants. It is a basic infrastructure of the city. It provides important support for the normal operation of the city. It is also a huge biochemical reaction system as the municipal sewage collection, transportation and processing system. The waste gases, such as CH4 and H2S, have been threatening the normal operation and life of municipal workers, affecting the life and health of urban residents. The monitoring and control of these toxic and harmful gases have attracted the attention of the government and the public. In this paper, the production and discharge of waste gas from the septic tank and various inspection wells in Kunming municipal sewage discharge system are mainly studied in this paper, and the emission coefficient of exhaust gas production of urban living drainage system in Guangzhou and Lanzhou is combined with the project group. The following research work has been carried out:
(1) on the basis of literature survey, expert consultation and preliminary measurement, the characteristic pollution factors of urban living drainage system waste gas are determined, and the emission rules of urban living drainage system waste gas are studied, and the formation of waste gas in urban sewage discharge system and its influencing factors are systematically analyzed.
(2) through the laboratory simulation study, the data of pollutant degradation and waste gas production of municipal sewage in the functional area under different conditions are obtained, and the dynamics law of the sewage is studied by means of the model analysis tool software.
(3) using the method of combining field measurement and laboratory simulation, the number of exhaust emissions of urban living drainage system based on the acquisition of Statistics (such as population, sewage drainage, length of urban life and drainage pipeline length or unit pollution load) is set up, and the calculation method of characteristic exhaust emission is constructed, and the preliminary estimate of the principal is made. The emission of the exhaust pollution index.
Through the field measurement and simulation experiment of Kunming municipal sewage drainage system, the production and discharge laws of the waste gas in the drainage system are studied, and the quantity of the characteristic waste gas in the urban sewage drainage system is calculated. The following conclusions are drawn.
(1) the production and discharge of the characteristic exhaust gas has a period of time, which is reflected in the peak period of water use and the low peak period within one day. It also reflects the difference between the working day and the non working day in one week. In the peak period of water use, the output of various characteristics of the exhaust gas is obviously higher than that of the low peak period of water. The drainage system has great influence, but has no influence on the drainage system. In the drainage well, the level of the sewage flow is high, which is beneficial to the diffusion of the waste gas from the liquid to the gas phase, which leads to the increase of the discharge of the exhaust gas in the drainage system.
(2) the waste generation and emission units of urban living drainage systems are mainly concentrated in septic tanks and various inspection wells, especially in the production and discharge of septic tanks. In general, the H2S and C02 gas bodies can only be monitored in the inspection wells (including sanded wells, slime wells and plunge wells, etc.), and septic tanks can monitor H2S, CO2 and CH4, septic tanks and inspection. Compared with the well, its anaerobic degree is higher, the concentration of C02 in the septic tank is higher than that of the inspection well, which is because the waste water in the septic tank is generally 12-24h. The long residence time is beneficial to the anaerobic degradation reaction of the sewage organic matter and the increase of the waste gas accumulation. The sediment will deposit a large amount of sediment in the bottom of the septic tank, which is beneficial to the production of CH4 gas.
(3) due to the different water quality and water in each functional area, the discharge of the exhaust gas of the drainage system in each district is different. The concentration of COD in the wastewater in the catering area is obviously higher than that of the other three functional areas, and the discharge rate of the H2S and C02 gas in the catering area is higher than that in the residential area.
(4) through the simulation experiments, the main factors affecting the biochemical reaction of domestic sewage in the drainage system are the hydraulic retention time (Hydraulic Retention Time, HRT), the concentration of organic matter, the pH value and the water temperature, and the main factors affecting the discharge into the urban atmosphere are the degree of hydraulic turbulence, and the influence of the drainage system on the production and discharge of the exhaust gas. This is mainly reflected in the increase of gas emission in the combined sewer system due to the increase of pipeline fullness in the rainy season.
(5) according to the simulation experiment results of domestic sewage, the relationship between COD degradation and CH4 production in sewage is obtained. The degradation coefficient constant of substrate is KH=0.0164h-1 and the fitting equation is -1n (X0/Xt) =0.0164t-0.21 with the first order kinetic equation; when pH is 6.9, the maximum final concentration of CH4 is 5.80g/m3, and the resident living pollution is 25 degrees C. The final concentration of water CH4 9.18g/m3.
(6) a comparative study of the production and discharge coefficient of CH4 in urban sewage drainage system and the recommended values in the IPCC list guide can be found that the maximum production coefficient of CH4 provided by the IPCC guide is 0.25gCH4/gCOD, and the septic tank CH4 emission coefficient is 0.125gCH4/gCOD., the pollution factor is 3.6 times of the pollution factor of Lanzhou, and the pollutant discharge coefficient is 10 of the pollution factor of Lanzhou. The CH4 discharge coefficient of the IPCC is 43 times the discharge coefficient of Kunming septic tank and 33 times the sewage discharge coefficient of the septic tank in Kunming. It is estimated that the production of H2S gas produced in the drainage system in 2011 is 7.96t/a, the emission is 1.46t/a, the emission rate is 18.30%, the CH4 gas production is 109.52t/a, the emission amount is 44.63t/a, the emission rate is 40.74%, C02 gas production is 957.69t/a, emission is 300.13t/a, and emission rate is 31.00%.
The research results of this paper not only provide the sewage discharge coefficient of urban living drainage system in Kunming, but also show that the proposed value of the CH4 emission coefficient of urban wastewater treatment in the IPCC list guide is rather large, which provides basic data for the accounting of urban greenhouse gas. The management of municipal drainage system has been applied, which has good guidance and reference for the research of waste gas production and pollution control and exhaust control in other domestic sewage drainage systems.
【学位授予单位】：昆明理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：X701;TU992

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