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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Evaluation of capacitance moisture sensors for use in municipal solid waste

Schmidt, Patrick 03 March 2010
Current municipal solid waste (MSW) practices have encouraged rapid waste degradation (stabilization) as an alternative to past methods of isolating the waste from the surrounding environment. There are challenges to rapid-stabilization technology, in particular, the management of the in-situ MSW moisture content.<p> The primary objective of this study was to evaluate the use of capacitance moisture probes for the purpose of measuring the moisture content within MSW. Capacitance moisture probes have not previously been used in MSW, however their use in agriculture is extensive and knowledge of their potential for monitoring MSW is limited.<p> The specific objectives of this research were to: i) establish a laboratory based correlation between sensor data and volumetric moisture content in MSW, ii) establish a correlation between field-installed capacitance sensors and moisture content derived from continuous-depth in-situ sampling of MSW, and iii) demonstrate the ability of capturing advancing/receding moisture fronts with the field-installed capacitance sensors.<p> Laboratory trials were conducted using hand-compacted MSW at volumetric moisture contents ranging from 15%-55% and a manual type of capacitance sensor. This series of laboratory trials successfully produced a correlation between sensor output and volumetric moisture content.<p> To evaluate the sensors in a real-world application, two configurations of capacitance moisture probes were installed in the field: i) an in-place, continuous-time capacitance probe, and ii) a portable, continuous-depth at discrete time, capacitance probe.<p> Field results indicated that capacitance moisture probes were able to capture the passing of both an artificially and naturally induced moisture front, though quantitative correlation between the in-situ moisture content of the sampled MSW and the readings of the sensors could not be achieved.<p> The reasons for this were a combination of three factors:<p> 1. The introduction of void-space during sensor installation significantly reduced sensor output;<p> 2. Poor MSW sampling technique resulted in 57% recovery (causing the exact origin of samples to be unknown); and<p> 3. The sampling technique disturbed the MSW samples, resulting in incorrect volumetric moisture contents in the samples.
12

A Systematic Comparison of Municipal Solid Waste Management Systems: Case Studies of Dalian City, China and the Region of Waterloo, Canada

Chen, Xudong 06 1900 (has links)
Since the 1990s, Municipal Solid Waste Management (MSWM) has shifted to a more comprehensive approach with an emphasis on managing Municipal Solid Waste (MSW) through the whole process from generation to disposal. Meanwhile, developing countries started to alter their ways of managing wastes and engage in more efforts on waste diversion. Due to their shortage of both resources and expertise, developing countries usually refer to and learn from developed countries’ experiences in MSWM to improve their own practices. How and to what extent these experiences are helpful for developing countries remains inconclusive because significant differences are present among MSWM systems in different countries. These differences do not simply reflect the variations in regulations and resource allocation; more importantly, they reflect the variations in the underlying connections between MSWM and other social, economic, demographic, and technological conditions. Therefore, a systematic examination is needed to enhance the understanding of these differences, the reasons for these differences, and the priorities that need to be stressed in order to improve waste diversion in a particular case. A systematic model, as the framework for the comparison in this thesis, is proposed to illustrate MSMW systems. Based on the model, this thesis compares and contrasts two cases, the Regional Municipality of Waterloo (RMOW) in Canada and Dalian City in China, at multiple levels: overall stage, system components, system structures, and interactions. The results show that Dalian, compared with the RMOW, has less sufficient capacities for waste planning and implementation. Challenges in MSWM are associated with higher density of residences, difficulties in managing informal profit-driven recycling activities, insufficient and unreliable treatment capacity, insufficient multi-agent dialogues and cooperation both within the government and between the public and private sectors, and less specific, program-based public education. The majority of participants in the RMOW are more self-motivated as opposed to the majority in Dalian who are motivated more by compensations. Based on the comparison, implications and suggestions in several aspects concerning waste planning are discussed. From the systematic perspective, to improve waste diversion in Dalian requires collaborative efforts of multiple agents. The key aspect is to strengthen the relatively incompetent component in the system to improve the capacities for waste service and treatment, which are contingent on the development of waste industries. In Dalian, waste diversion should begin with limited types of wastes and gradually expand the scope, and new programs should be designed based on the existing system with cooperation of the informal sector. Meanwhile, cooperation among governmental divisions and between public and private sectors need to be promoted by encouraging multi-agent dialogues and improving information transparency. Program promotion also needs to be more specific in instructions and to address both pro- environmental attitudes and service quality and convenience. Finally, scavenging at landfill sites should be discouraged in order to protect scavengers from the detrimental working environment.
13

Waste Management with Focus on Waste incineration with energyrecovery in Chisinau Municipality, Moldova

Gunnarsson, Martin, Johannesson, Rickard January 2010 (has links)
The amount of waste in the world increases every year due to an improved living standard andgrowing population. The problem is especially large in poor countries where the ability tohandle the waste is limited due to financial and management problems. If instead wastematerial is seen as a resource it can help reduce the amount of waste on landfill. Byincinerating waste and recover the energy it would also help reducing greenhouse gasemissions from landfill and give electric and thermal energy.Chisinau Municipality in the Republic of Moldova today lacks several important parts fora satisfying waste management. Today most of the waste generated in Chisinau municipalityends up at the municipality landfill. The current contract to use the landfill expires on the 31December 2010, if the municipality won’t be able to renew the contract they have to look forother ways to deal with the waste problem. As the dominating source for energy in Chisinau isimported natural gas, an effective way to reduce the use of gas for electricity and thermalenergy production would be to use waste material for incineration with energy recovery.Therefore, the goal with this thesis is to evaluate the possibility to extract energy from coincinerationof sewage sludge and waste material generated in Chisinau. To reach this goal thesituation in Chisinau where studied on site for two months, quantities and composition of thewaste material was investigated. Based on the data gathered on the waste, a suitabletechnology for the waste-to-energy (WTE) plant is proposed. The proposal is made based onthe assumption that a WTE plant would not be established until 2025.The result shows that the waste material in Chisinau can be used for co-incineration ofwaste and sludge. The calorific value of the waste material was determined to 7.87 MJ per kg.The suggested WTE plant has the total power of 138 MW, the result based on that all wastematerial available 2025 are incinerated. Annually this makes it possible to recover 1152 TJ(320 GWh) electric power and 2650 TJ (736 GWh) heat, based on 8000 operating hoursannually.Even if a WTE plant sounds like a good investment it is a long time before a plant couldoperational. Much is to be made in the waste management to have well-functioninginfrastructure that will work together with an incineration plant. Furthermore, the data used inthis study regarding the quantities is very uncertain and further studies in affected areas arenecessary before a WTE plant can be established. / Den totala mängden avfall i världen ökar varje år som följd av ökad folkmängd ochlevnadsstandard. Problemet är extra påtagligt i fattiga länder med begränsade ekonomiskaresurser för att ta hantera avfallet. Om avfallet istället skulle ses som en resurs skulle detkunna reducera andelen avfall som läggs på deponi. Genom att förbränna avfallet medenergiåtervinning skulle också växthusgaserna från deponering minska och samtidigt geelektrisk och termisk energi.Chisinau kommun i Republiken Moldavien saknar idag flera vitala delar iavfallshanteringen. Idag slutar den största delen av avfallet som produceras i Chisinaukommun på den kommunala deponin. Kontraktet för att använda deponin löper ut den sistadecember 2010, om Chisinau kommun inte tillåts förnya kontraktet är det nödvändigt att sesig om efter nya lösningar för avfallshanteringen. Eftersom den dominerande källan för energii Chisinau är importerad gas, skulle ett effektivt sätt att reducera gasanvändningen vid el ochtermisk energiproduktion att förbränna avfall med energiåtervinning.Av den orsaken är målet med studien att utvärdera möjligheterna att utnyttjasamförbränning med energiåtervinning av avfall och avloppsslam från Chisinau kommun. Föratt nå detta mål har den nuvarande situationen i Chisinau kommun studerats på plats under tvåmånaders tid, detta för att undersöka vilka mängder avfall som årligen produceras och huravfallets fraktionsfördelning ser ut. Baserat på de data som samlats in föreslogs en lämpligavfallsförbränningsanläggning. Förslaget är baserat på antagandet att enavfallsförbränningsanläggning inte är etablerad förrän tidigast 2025.Resultatet visar att det är möjligt att samförbränna avloppsslam och avfall i Chisinau. Detkalorimetriska värmevärdet för avfallet och slammet har bestämts till 7.87 MJ per kg. Det irapporten presenterade förslag på kraftvärmeverk för avfallsförbränning kommer att ha entotal effekt av 138 MW, resultatet är baserat på att allt tillgängligt kommunalt avfall 2025förbränns. Kraftvärmeverket beräknas årligen utvinna TJ (320 GWh) elektrisk energi och2650 TJ (736 GWh) termisk energi, beräknad på 8000 drifttimmar årligen.Även om en avfallsförbränningsanläggning låter som en god investering så ligger detlångt fram i tiden innan en sådan anläggning är möjlig att etablera. Först måste en brafungerande infrastruktur som fungerar tillsammans med avfallsförbränningsanläggningenupprättas. Vidare bör poängteras att de data som använts i denna studie gällandeavfallsmängder är ytterst osäkra och ytterligare studier inom området krävs innan enavfallsförbränningsanläggning kan etableras.
14

A Systematic Comparison of Municipal Solid Waste Management Systems: Case Studies of Dalian City, China and the Region of Waterloo, Canada

Chen, Xudong 06 1900 (has links)
Since the 1990s, Municipal Solid Waste Management (MSWM) has shifted to a more comprehensive approach with an emphasis on managing Municipal Solid Waste (MSW) through the whole process from generation to disposal. Meanwhile, developing countries started to alter their ways of managing wastes and engage in more efforts on waste diversion. Due to their shortage of both resources and expertise, developing countries usually refer to and learn from developed countries’ experiences in MSWM to improve their own practices. How and to what extent these experiences are helpful for developing countries remains inconclusive because significant differences are present among MSWM systems in different countries. These differences do not simply reflect the variations in regulations and resource allocation; more importantly, they reflect the variations in the underlying connections between MSWM and other social, economic, demographic, and technological conditions. Therefore, a systematic examination is needed to enhance the understanding of these differences, the reasons for these differences, and the priorities that need to be stressed in order to improve waste diversion in a particular case. A systematic model, as the framework for the comparison in this thesis, is proposed to illustrate MSMW systems. Based on the model, this thesis compares and contrasts two cases, the Regional Municipality of Waterloo (RMOW) in Canada and Dalian City in China, at multiple levels: overall stage, system components, system structures, and interactions. The results show that Dalian, compared with the RMOW, has less sufficient capacities for waste planning and implementation. Challenges in MSWM are associated with higher density of residences, difficulties in managing informal profit-driven recycling activities, insufficient and unreliable treatment capacity, insufficient multi-agent dialogues and cooperation both within the government and between the public and private sectors, and less specific, program-based public education. The majority of participants in the RMOW are more self-motivated as opposed to the majority in Dalian who are motivated more by compensations. Based on the comparison, implications and suggestions in several aspects concerning waste planning are discussed. From the systematic perspective, to improve waste diversion in Dalian requires collaborative efforts of multiple agents. The key aspect is to strengthen the relatively incompetent component in the system to improve the capacities for waste service and treatment, which are contingent on the development of waste industries. In Dalian, waste diversion should begin with limited types of wastes and gradually expand the scope, and new programs should be designed based on the existing system with cooperation of the informal sector. Meanwhile, cooperation among governmental divisions and between public and private sectors need to be promoted by encouraging multi-agent dialogues and improving information transparency. Program promotion also needs to be more specific in instructions and to address both pro- environmental attitudes and service quality and convenience. Finally, scavenging at landfill sites should be discouraged in order to protect scavengers from the detrimental working environment.
15

Evaluation of capacitance moisture sensors for use in municipal solid waste

Schmidt, Patrick 03 March 2010 (has links)
Current municipal solid waste (MSW) practices have encouraged rapid waste degradation (stabilization) as an alternative to past methods of isolating the waste from the surrounding environment. There are challenges to rapid-stabilization technology, in particular, the management of the in-situ MSW moisture content.<p> The primary objective of this study was to evaluate the use of capacitance moisture probes for the purpose of measuring the moisture content within MSW. Capacitance moisture probes have not previously been used in MSW, however their use in agriculture is extensive and knowledge of their potential for monitoring MSW is limited.<p> The specific objectives of this research were to: i) establish a laboratory based correlation between sensor data and volumetric moisture content in MSW, ii) establish a correlation between field-installed capacitance sensors and moisture content derived from continuous-depth in-situ sampling of MSW, and iii) demonstrate the ability of capturing advancing/receding moisture fronts with the field-installed capacitance sensors.<p> Laboratory trials were conducted using hand-compacted MSW at volumetric moisture contents ranging from 15%-55% and a manual type of capacitance sensor. This series of laboratory trials successfully produced a correlation between sensor output and volumetric moisture content.<p> To evaluate the sensors in a real-world application, two configurations of capacitance moisture probes were installed in the field: i) an in-place, continuous-time capacitance probe, and ii) a portable, continuous-depth at discrete time, capacitance probe.<p> Field results indicated that capacitance moisture probes were able to capture the passing of both an artificially and naturally induced moisture front, though quantitative correlation between the in-situ moisture content of the sampled MSW and the readings of the sensors could not be achieved.<p> The reasons for this were a combination of three factors:<p> 1. The introduction of void-space during sensor installation significantly reduced sensor output;<p> 2. Poor MSW sampling technique resulted in 57% recovery (causing the exact origin of samples to be unknown); and<p> 3. The sampling technique disturbed the MSW samples, resulting in incorrect volumetric moisture contents in the samples.
16

Municipal Solid Waste Management in an urban area of China: Case studies of Shanghai, China and Linköping, Sweden.

Yang, Cha January 2011 (has links)
With the rapid and large increase of waste quantities, China, surpassed the USA as the world’s largest municipal solid waste (MSW) generator since 2004. The phenomena and critical issues of MSWM in China inspired this paper to investigate and analyse the MSWM in an urban area of China. Comparing with the increasing rates of MSW generation, little has been done concerning the municipal solid waste management (MSWM). Not only the local government and authorities are responsible for the MSWM, but also the individuals are playing a significant role in MSWM. An integrated waste management system should be built in order to improve the holistic MSW system and reduce the waste production. The aim of the study is to investigate and analyse the current status and problems of MSWM in an urban area of China and to analyse to what extent a viable reduction of the MSW can be implemented and management systems to be improved in the near future. In this study, two case studies of Shanghai and Linköping are employed and compared to explore the challenges and potentials for improving the MSWM system in China. The result indicated that inadequate facilities and infrastructure, less advanced technology, insufficient public participation, low awareness of environmental protection, problems in policy and laws are the major barriers for the improvement of MSWM. Involving international environmental cooperation activities, planning a sustainable and comprehensive policy and framework for MSWM, introducing economic incentive approaches, promoting the capacities of waste management technologies, raising public environmental awareness are believed to be viable solutions to improve the MSWM system in China.
17

An evaluation of potential benefits from the redevelopment of landfills into parks in Houston, Texas

Taylor, Michael Lawrence 21 November 2013 (has links)
This report examines the potential benefits from the redevelopment of landfills into parks in Houston, Texas. Many Park and Recreation (P&R) Departments are unable to acquire and develop parkland at a rate on par with new residential construction. Parks provide economic, environmental, public health and aesthetic benefits. Despite these benefits, P&R Departments are often the target of budget cuts when city governments grapple with funding shortfalls. P&R Departments must pursue low value lands to meet parkland needs. Closed Municipal Solid Waste (MSW) landfills are a source of low value land in, and surrounding urban areas. New regulatory framework in the form of the U.S. EPA’s Municipal Solid Waste Landfill Criteria ensures closed landfills may be safely and cost effectively redeveloped for recreational use with limited liability concerns for the P&R Department. This regulatory framework is discussed and Best Management Practices (BMPs) are outlined. These BMPs focus on accommodating the dynamic nature of landfills to minimize park development and Operation and Maintenance (O&M) costs. The substantial parkland deficit in the City of Houston is quantified. The findings of the needs assessment in the City’s Parks Master Plan are presented. A multi-tiered Geographic Information Systems (GIS) based analysis is utilized to evaluate the potential benefits from the redevelopment of existing landfills in the City into parks. The GIS analysis identified 8 landfills that, if redeveloped, will increase the distributional equity of City parkland holdings. Of these 8, the 4 landfills with the lowest expected total development costs and the highest expected savings over traditional greenfield development were identified. It is recommended the City adopt a thorough site characterization and planning process and pursue landfill redevelopment as a cost effective and beneficial way to increase parkland holdings. / text
18

Prefeasibility Study for a Waste-to-EnergyApplication in Gauteng Province, South Africa

Subasinghe, Gayan January 2013 (has links)
Waste-to-Energy concept becomes increasingly popular from the perspectives of the waste management and alternative energy. South Africa, which is a country heavily dependent on the fossil fuel, can explore the opportunities of Waste-to-Energy in order to deal with increasing amount of waste generated while reducing what is deposited at non-engineered landfills, thereby increase the renewable energy share. This prefeasibility study attempts to identify Waste-to-Energy potentials in Gauteng provinceso as to develop a Waste-to-Energy facility under the new renewable Independent Power Producer procurement programme of South Africa. The analysis identifies abundant Wasteto-Energy incineration and landfill gas opportunities linked with municipal solid waste in twomunicipalities. The prefeasibility study further evaluates environmental, socio-economic aspects of Waste-to-Energy initiative. The financial viability of a Waste-to-Energy incineration facility with the Feed-in-Tariff proposed by the government of South Africa isalso detailed analysed.
19

Sustainable municipal solid waste management: A qualitative study on possibilities and solutions in Mutomo, Kenya

Selin, Emma January 2013 (has links)
This report investigates the possibilities and solutions for a sustainable municipal solid waste management in the community of Mutomo, situated in Kitui County, Kenya. The aim was to formulate an action plan to start reaching for a sustainable development in the waste sector, with citizen participation. Specific research questions were to find requests and ideas from the community members. Also, how the Swedish solid waste management system is built up in order to find potential good examples. Qualitative methods for data collection were used both in-depth interviews and focus group discussions conducted. Data collection was done with the help of an interpreter; interviewing guides and a recording device were used. The data was transcribed and thematic analysis done using NVivo. The interviews and discussions resulted in many requests and ideas regarding solid waste management. In brief; a legal dumping site, health education of the advantages of managing waste and the disadvantages if not, increase of public dustbins, increase of people employed for waste collection, an organized system for trade of waste and improved future planning of the town by the local authorities. To conclude, if a sustainable development within the waste sector is to be initiated, the local authorities have to take action and shoulder their responsibility. Improved collaboration between them and the public health office, community members and private stakeholders is essential. The proposed action plan is a good tool to use when initiating this work and would be created through co-operation with residents in Mutomo.
20

Mathematical modeling of municipal solid waste plasma gasification in a fixed-bed melting reactor

Zhang, Qinglin January 2011 (has links)
The increasing yield of municipal solid waste (MSW) is one of the main by-products of modern society. Among various MSW treatment methods, plasma gasification in a fixed-bed melting reactor (PGM) is a new technology, which may provide an efficient and environmental friendly solution for problems related to MSW disposals. General objectives of this work are to develop mathematical models for the PGM process, and using these models to analyze the characteristics of this new technology. In this thesis, both experimental measurement and numerical analysis are carried out to evaluate the performance of both air gasification and air&amp;steam gasification in a PGM reactor. Furthermore, parameter studies were launched to investigate the effect of three main operation parameters: equivalence ratio (ER), steam feedstock mass ratio(S/F) and plasma energy ratio (PER). Based on the above analysis, the optimal suggestions aiming at providing highest syngas calorific value, as well as system energy efficiency, are given. Six experimental tests were conducted in a demonstration reactor. These tests are classified into two groups: air gasification (case 1 and 2) and air&amp;steam gasification (case 3 to 6). In all these cases, the plasma gasification and melting of MSW produced a   syngas with a lower heating value of 6.0-7.0 MJ/Nm3. By comparing the syngas yield and calorific value, the study found out that the steam and air mixture is a better gasification agent than pure air. It is also discovered that the operation parameters seriously influence the operation of the PGM process. A zero-dimensional kinetic free model was built up to investigate the influence of operation parameters. The model was developed using the popular process simulation software Aspen Plus. In this model, the whole plasma gasification and melting process was divided into four layers: drying, pyrolysis, char combustion&amp;gasificaiton, and plasma melting. Mass and energy balances were considered in all layers. It was proved that the model is able to give good agreement of the syngas yield and composition. This model was used to study the influence of ER, S/F and PER on average gasification temperature, syngas composition and syngas yield. It is pointed out that a common problem for the PGM air gasification is the incomplete char conversion due to low ER value. Both increasing plasma power and feeding steam is helpful for solving this problem. The syngas quality can also be improved by reasonably feeding high temperature steam into the reactor.   In order to provide detailed information inside the reactor, a two-dimensional steady model was developed for the PGM process. The model used the Euler-Euler multiphase approach. The mass, momentum and energy balances of both gas and solid phases are considered in this model. The model described the complex chemical and physical processes such as drying, pyrolysis, homogeneous reactions, heterogeneous char reactions and melting of the inorganic components of MSW. The rates of chemical reactions are controlled by kinetic rates and physical transport theories. The model is capable of simulating the pressure fields, temperature fields, and velocity fields of both phase, as well as variations of gas and solid composition insider the reactor. This model was used to simulate both air gasification and air&amp;steam gasification of MSW in the PGM reactor. For PGM air gasification, simulated results showed that when ER varies from 0.043 to 0.077, both the syngas yield and cold gas efficiency demonstrated a trend of increasing. This is explained mainly by the increase of char conversion rate with ER. However, the increase of ER was restricted by peak temperature inside the fixed-bed reactor. Therefore, it is not suggested to use only air as gasification in the PGM process. The influence of plasma power is not obvious when PER varies from 0.098 to 0.138.  The positive influences of steam addition on cold gas efficiency and syngas lower-heating-value are confirmed by the simulation results of PGM air&amp;steam gasification. The main effect of steam addition is the rouse of water shift reaction, which largely accelerates the char conversion and final yields of hydrogen and carbon dioxide. The effect of steam injection is affected by steam feeding rate, air feeding rate and plasma power. Based on the above modeling work, Interactions between operation parameters were discussed. Possible operation extents of operation parameters are delimitated. The optimal points aiming at obtaining maximum syngas LHV and system CGE are suggested.

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