污泥与城市生活垃圾混填的力学特性及稳定性

工业污水和生活污水排放量日益增多,污水处理厂污泥产量日趋加大,污泥填埋关键技术问题已成为当今环境工程以及环境岩土工程的热点问题之一。污泥和垃圾混合填埋在其他国家已得到应用,但由于目前中国关于污泥及其城市生活垃圾混合样的基础性室内试验成果不多,对污泥与城市垃圾混合样的工程力学特性及其混合填埋的适宜比例等不甚了解,从而导致中国污泥垃圾混合填埋工程事故频繁发生。对不同配比的污泥与城市生活垃圾混合样进行了固结压缩实验、三轴固结不排水实验、无侧限抗压强度实验,得出污泥与城市生活垃圾混合样的工程力学特性;同时,用ANSYS数值模拟方法,对不同配合比的污泥城市生活垃圾混合填埋边坡的稳定性进行分析,从而对污泥与城市生活垃圾混合填埋的适宜配合比及其稳定安全问题提出理论支撑。     

Existing Situation on Disposal of Sludge from Wastewater Treatment Plant in Three-Gorges Reservoir Area

At present 18 wastewater treatment plants operateing in the Small towns of Three Gorge Areas of Chongqing Municipality, producing 132.95 tons surplus sludge everyday. As regards to the disposition of such numerous surplus sludge, the major disposition technique in these wastewater water treatment plants, i. e. , thickening and mechanical dewatering technique followed by feeding into the municipal solid waste landfill, seems to have a rather bad effect on the normal operation of the municipal solid waste landfill, due to the unstabilized sludge resulted from this technique of the sludge disposition and high moisture in the sludge, which is higher than 80%. This paper has paid some attention to this phenomenon. With respect to the small towns having the the municipal solid waste landfill, the techniques of mechanical dewatering, calcareousness stabilized etc. before feeding into the municipal solid waste landfill, seem to be feasible, while the composting and comprehensive utilization of sludge is available in the small towns which have no municipal solid waste landfills.     

Experimental Research on Municipal Solid Waste Landfill''s Strength Character in a Refuse Dump of Chongqing

With the development of economic and society,more and more waste landfill gradually threaten to the development of the city.Some special tests are done to study the relationship of the Municipal solid waste(MSW) strength and the stability of MSW landfill structure.A geo-technical test with the soil samples collected at the scene is done in the laboratory through direct sheared device and the thri-axial sheared device,the disciplinarian and factors are analyzed.The results are referenced to the design and construction of new-built MSW and finished rubbish field.It is shown that some parameters such as composition,particle magnitude,water content,compressing method,intensity and time,will greatly affect the strength character of MSW.     

One-dimensional Steady-state Model for Gas Pressure Distribution in Municipal Solid Waste Landfills

Gas pressure distribution in landfills is of great importance to control hazards and improve recovery of landfill gas. An one-dimensional steady-state model and its solving approach are presented for gas pressure distribution in layered waste landfills. The model can be used to investigate the gas pressure distribution of the landfill with horizontal gas collection layers having specified pressure or flux. The influences of layered properties, horizontal permeable layer under final cover and horizontal gas collection layers and bottom leachate drainage systems dually serving as gas collection layers on gas pressure distribution are investigated. The results of parameter analyses using the presented model show that the assumption that homogenizations of gas generation rate and gas permeability through a landfill considerably overestimate gas pressure in landfill; horizontal permeable layer under final cover and horizontal gas collection layers can effectively reduce gas pressure in landfills; the bottom leachate drainage systems dually serving as gas collection layers can significantly reduce the gas pressure in the lower portion of landfills. The presented model provides a useful tool in the designing of landfill gas collection systems, such as, the positions and spacing of horizontal gas collection layers and pump section.     

Sustainable Development and Municipal Solid Waste Disposal

Human beings are facing a lot of social, economical and environmental problems, so in 21st century, the sustainable development becomes inevitable choice of human beings. The current situation of municipal solid waste (MSW) and the merits and shortcomings of sanitation landfill, composting, incineration have been expatiated in this paper. If the MSW has been disposed according to the principle of reduction, harmless and resource transformation, the sound base for our country's sustainable development in 21st century will be set.     

MSW Treatment Techniques Informative for Chongqing

On the basis of the geographic, climatic characteristics and air pollution conditions of Chongqing city, referring to the application and development of Municipal solid waste (MSW) treatment techniques developed recently in advanced countries and other domestic cities, Varieties of MSW treatment techniques, incineration, landfill, composting, and comprehensive utilization, are analyzed in comparison. Their applying prospects and limitations in Chongqing are marked out.     

生活垃圾卫生填埋甲烷排放及减排研究进展

卫生填埋是生活垃圾最主要的处理方式,生活垃圾卫生填埋场产生甲烷(CH₄)等温室气体,加快全球气候变暖进程,引起各国政府的高度重视。笔者探讨了影响生活垃圾卫生填埋场CH₄产生的因素,对CH₄减排技术进行了总结。目前,生活垃圾卫生填埋场CH₄减排技术主要包括填埋层原位减排、资源化利用和末端控制技术等。为了控制和减少CH₄排放量,中国需要增加技术和设施投入,加强生活垃圾卫生填埋场气体排放的管理,开发有效的CH₄抑制技术,建立适合中国国情的CH₄等温室气体减排技术体系。     

固化污泥对渗滤液中氟阻滞作用的数值分析

固化污泥是一种新型填埋场底部防渗阻滞材料,为论证其防渗阻滞作用的有效性,需进行典型污染物的穿透试验,但由于固化污泥渗透性很低,采用常规土柱试验很难得到污染物透过其迁移时的相关参数。为解决该问题,用柔性壁渗透试验代替传统土柱试验。渗滤液中污染成分较多,取含量较高且较易穿透的污染物即氟离子作为典型污染物,首先进行穿透试验获得迁移参数,然后结合二维有限元法研究分析其在防渗阻滞层及周边岩土环境中60 a内的运动迁移范围、浓度分布情况,并对比分析未设防渗阻滞层的情况。研究表明,在填埋场底部设置固化污泥防渗层对于以氟为代表的阴性污染物有较好的延迟阻滞作用。由于阳性污染物的穿透能力较阴性污染物弱,因而固化污泥防渗层对重金属等阳性污染物也应具有较强的阻滞作用,从而能进一步延迟填埋场渗滤液对周边环境的污染。     

Carbon Emission and Low carbon Strategies of Sewage Sludge Treatment

The carbon emission during sewage sludge treatment is an important source of greenhouse gas. For the carbon reduction, the emissions from common treatment technologies are calculated with the mass balance model, then their low carbon degrees are evaluated, and finally the low carbon treatment strategies are put forward for different requirements. The results show that the technologies, such as digestion for methane recovery, incineration or co incineration for power production after drying with industrial waste heat, are the ones with the lowest carbon emission. Their low carbon degrees are 89.6%, 80.3% and 76.6% respectively. In the area where the above technologies cannot be applied, aerobic composting or landfill with aerobic stabilization pretreatment are the effective methods to reduce carbon emission. The low carbon treatment strategy, a new part of sludge treatment strategies, should be applied combining the local economy, technology and social conditions, so that it can meet the different requirements from sanitation to carbon emission reduction.     

Effects of Livestock Wastewater NH4 +-N Incubation on Landfill CH4 Oxidation by Mineralized Refuse Particle

Ammonia oxidizing bacteria was accumualted for landfill CH4 oxidation in the mineralized refuse throguh livestock wastewater NH4 +-N incubation, which would minimize the total Greenhouse gas emission equivalent from MSW landfill. Mineralized refuse was firstly incubated by livestock wastewater NH4 +-N during the 120d operation. Mineralized refuse possessed the strong nitrification capacity with the removal rate of NH4 +-N content over 60% during the 120 d operation. After 200 mg N kg -1 was inputted, NO3 --N content produced from the 120 d incubated mineralized refuse was 2.0-time and 3.8-time more than those of the original mineralized refuse and clay soil, respectively. CH4 decrease and the net produce of CO2 can be well fitted the one- and zero-order kinetics model during the 120 h incubation (R 2>0.68), respectively. Similar as nitrogen turnover, CH4 oxidation capacity from the 120 d incubated mineralized refuse was 10.6% and 59.3% more than those of the original mineralized refuse and clay soil, respectively. Therefore, the mineralized refuse can be upgraded for the CH4 oxidation throng NH4 +-N content incubation from the livestock wastewater and the influence on CH4 oxidation by other components (including CODCr, SS and phosphate) from wastewater should be further investigated.     

Degradation Settlement Model of Municipal Solid Wastewith the Degradation Rate

By the law of conservation of mass, one dimensional municipal solid waste(MSW) degradation model was proposed with considering the degradation and density fluctuation, the relationship between density, quality and volume and the degradation characteristics obtained from the degradation test.With the analysis, it was found that the settlement of degradation was positive proportional with the following three elements: the volume percentage of organic matter, the rate of degradation and the initial height.As a case study, the degradation settlement of Chongqing MSW landfill was predicted.And it was found that the relationship between the settlement and the time showed exponential attenuation trend, in which the degradation settlement of MSW landfill was large in the initial stages, and then it gradually stabilized with the time.     

Pressure Distribution of LFG in a Landfill with Vertical Extraction System

In present engineering practice of landfill gas pollution control and its recovery, technical parameters such as extraction flow and radius of influence of a extraction well must be determined by field tests. A mathematical model for LFG migration under a vertical extraction well is established, which comprehensively reflects affects of several parameters including LFG generation rate, extraction flow, air permeability, buried depth of a extraction well and features of the cover layer. By using the model, pressure distribution of LFG around a vertical extraction well in a landfill can be calculated, the radius of influence of the well can also be determined.     

Greenhouse Gas Control for Landfill

Landfill site is one of the most important sources of greenhouse gas emissions. The available information shows that greenhouse gas emissions from the landfill sites are 40% 50% of the total greenhouse gas emissions in America. The greenhouse gas output is computed in the text and the conclusion that the main components of yielding gas are food and paper is made. Some measures of cutting greenhouse gas yielding are suggested. At last it points out that some research about these measures should be made in the future in China.     

Experiment Research on Leachate Treatment of Sanitary Landfill for Municipal Solid Waste

It is difficult to treat landfill leachate in China.Traditional biologic method and physical method always have high expenses,or cann''t reach the discharge standards.The authors use a new biologic method to treat landfill leachate,which is the Wood_microbial System from Japan.The system to be digested by 3 aeration tanks and 1 reaction tank.The comparison combine processed wool_dust broken pieces with the certain grain degree size were throw in the tanks.Dirty and organic matter are in the digest tanks through the aeration reaction and aneration reaction repeatedly.In this experiment the speed of wastewater discharge and oxygen supply has been changed, and the change of biologic system and the effect of pollutant are removed. The optimal treatment condition can be found.The experiment shows that the system has a good result,special for nitrogenous.The BOD is average to do away with the rate to amount to 90%,almost reach the second class or third class for leachate standard.But BOD loading should be not beyond 4 kg/(m 3.d),othrwise,the system will not operate in normally.     

Measures of Rainwater and Sewage Shunting in Chongqing Changshengqiao Sanitary Landfill

This paper focuses on the measures of rainwater and sewage shunting in Chongqing Changshengqiao sanitary landfill. The catchment area of this landfill is totally about 331700 square meters. If the rainwater blends with the sewage, the processing load of the leachate will increase greatly. Thus, the measures of rainwater and sewage shunting must be taken during solid waste filling. In this paper, the authors firstly analyze the measures of rainwater collection and drainage and establish the guideline of pumping assisted by draining. Furthermore, according to the practical situation of landfill, a detailed plan is set down for rainwater and sewage shunting. The effect is quite evident after implementation of the plan for half a year. The processing load of the leachate has been reduced largely. It is proven that the shunting measures are feasible.     

Analysis of Landfill Gas Production and Its Affecting Factors

On the basis of analyzing the landfill gas production and its affecting factors, the methods for accelerating the production of landfill gas and settlement of landfill site are put forward in this paper.     

A Review on Medical Waste Management and Treatment in Chongqing Three Gorges Region

Medical waste ,belonging to one of top-ronking toxic wastes, should be safely deposed of. The characteristics and harmness of the medical wastes are introduced, and the practical status of medical wastes in Chongqing three gorges region, including waste management and disposal methods, is investigated. Because of the special characteristics of the waste, the paper proposes some measures for managing and separate collection and treatment in the region, including separate collection, sealed transportation, pretreatment, incineration and safe landfill, so that the ecological environment and water resource can be protected from pollution in the Three Gorges region.     

Assessment of Gas Utilization for Landfill

In order to fulfill the landfill gas's energizing and protect the environment, many measures to control and exploit the landfill gas are taken. In this paper, a targets system and an analytic hierarchy process method which assesses the measures are put forward based on the systematic impact of environmental,economical and social benefits. It is useful to make a decision reasonably.     

Performance Analysis of the Timeslot Synchronous in the Upstream Channel for the HFC Networks

In this paper, in the light of the percolating flow mechanics problems in the field of environmental science research , the transport mechanism and law of the volatile organic pollutants in the soils and the transport model and law of the underground water multi-component reacting solute are discussed, and the gas transport and the second pollution problems in the solid waste landfill are analyzed~ Based on the research given above, the transport process and two aspects of the control mechanisms uncertainty for the volatile organic matter and the necessity to establish the coupling model of multi-component water chemistry model and waterdynamic transport model are pointed out. The result is of great theoretical importance and practical significance to the further understanding of the overlapping research problems in environmental science and percolating flow mechanics.     

Leachate Generation of Solid Waste Sanitary Landfill

The paper analyses the factors affecting leachate generation for landfill,and discusses the methods of calculation for leachate generation and indicates the effective ways to control leachate pollution on environment.