Surface mining operations extract a large quantity of waste material,which is generally disposed into a dump area.This waste can cause a series of environmental problems ranging from landscape deterioration to acidic ...Surface mining operations extract a large quantity of waste material,which is generally disposed into a dump area.This waste can cause a series of environmental problems ranging from landscape deterioration to acidic water generation and water pollution.Therefore,mine waste management is a significant task in mining operations.As known,in strip mining,the overburden is not transported to waste dumps but disposed directly into adjacent strip which was mined out.This concept can be adapted for mine planning of relatively horizontal deposits through a mixed integer programming(MIP)model.The main idea behind this work is that,in one pit,production voids created in early year of mining are used for waste landfilling in late years of production.In other words,in addition to external dumping,a landfilling option within the same pit is proposed for mine design optimization.The problem is formulated as maximization of the net present value(NPV)of the mining project under the constraints of access,landfill waste handling,mining and processing capacities.A case study using a data set was carried out to see the performance of the proposed approach.The findings showed that this approach could be used in waste management incorporating a landfilling option into mine planning.As a result,material handling costs decrease,and environmental compliance increases due to less external waste quantity.展开更多
A survey of major chicken meat hatcheries in Australia was undertaken in 2008 to identify how hatchery waste is currently managed. A weekly average of 10.4 tonnes of waste is produced by chicken meat hatcheries. The c...A survey of major chicken meat hatcheries in Australia was undertaken in 2008 to identify how hatchery waste is currently managed. A weekly average of 10.4 tonnes of waste is produced by chicken meat hatcheries. The cost of disposal （average $127/tonne） and availability of disposal sites is an emerging issue. The majority of hatchery waste is sent to land fill or for composting, with some rendered for use as pet food. Hatchery wastewater is mostly used for irrigation or disposed directly into the sewer. Most of the hatcheries have no environmental issues with hatchery waste on site but some report odour problems. Some hatcheries would like to treat the waste on site so that it could be sold as a commodity or to use methods to separate liquid from solid waste and recycle water.展开更多
Solid waste management in developing countries has assumed the scale of a major social and environmental challenge. However, many developing countries such as Nigeria have a chronic solid waste management problem. Poo...Solid waste management in developing countries has assumed the scale of a major social and environmental challenge. However, many developing countries such as Nigeria have a chronic solid waste management problem. Poorly managed solid waste in market has resulted in health hazards and environmental disaster due to contamination by vermin. This paper studies the management of solid waste in Bodija market, Ibadan, Nigeria. The study adopted a quantitative approach, employing waste composition analysis of samples from the case study area, and questionnaire survey as key methods for data generation. Analysis of result reveals poor collection practise in the market with 6.7% respondents practicing open burning of refuse. However, high rate of waste generation in the market, inconsistency and inefficiency of the private collection agents and lack of funds on the part of the waste management authority has led to this practise. In the next two decades, a total volume of 282,000 m3 of landfill site would be needed for solid waste disposal in the market. The sanitary landfill technique has the potential to reduce environmental health problems created by the existing disposal methods. Hence, cost recovery practises and reconstruction of management capacity are recommended as solutions to the problem.展开更多
The most prevalent way of disposing solid waste in most of the developing countries is open dumping which is the easiest and considered to be the cheapest method of removing waste from the immediate environment. The i...The most prevalent way of disposing solid waste in most of the developing countries is open dumping which is the easiest and considered to be the cheapest method of removing waste from the immediate environment. The increasing awareness on public health and environment quality concerns are expected to provide the impetus that is needed to develop and implement a sustainable approach to manage solids. An inventory of these locations, the types of waste handled and management processes for waste products will aid in the assessment of the polluting capability of such sites. This paper discusses research experiences gathered during a study that was undertaken in three Kenya dumpsites to explore the potential for utilising the waste for energy generation in a low-income economy and at the same time, address worsening disposal challenges.展开更多
Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and it...Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and its adverse health effects, studies on anthropogenic contributions to the increasing levels of GHG, particularly from livestock waste management practices, have not been adequately explored, especially in less developed countries. This study determined waste management practices and outdoor levels of CH4 and CO2 at three selected livestock farms （A-C） in Ibadan, Oyo State, Nigeria. Each study farm consisted of poultry, cattle and pig units. A 30-point observational checklist documented adequacy of solid waste management practices. Ambient concentrations of CH4 and CO2 at farm buildings and at waste disposal sites were monitored every other day, twice each day of monitoring （morning and evening hours）, for eight weeks during months of September-November in 2013. Average scores for the waste management practices for Farms A-C were 29.6%, 33.3% and 18.5%, respectively. Morning and evening CH4 concentrations in parts per million （ppm） at main buildings of Farms A-C were 2,538 ± 773 and 1,916 ± 662, 2,325 ± 773 and 1,180 ± 483, and 2,389 ± 687 and 1,854 ± 571, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C main buildings were 350 ± 130 and 330 ± 110, 470 ± 100 and 440 ± 100, and 430 ± 80 and 400 ± 70, respectively. Morning and evening CH4 concentrations （ppm） at Farms A-C waste disposal sites were 2,452 ± 495 and 1,614 ± 372, 1,527 ± 390 and 1,736 ± 269, and 2,345 ± 615 and 1,690 ± 387, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C waste disposal sites were 330 ± 90, 370 ± 60 and 350 ± 30, respectively. Waste management practices were inadequate; solid waste management practices like infrequent evacuation of slurry waste and open burning of waste may have contributed to the production of CH4 and CO2. This study suggested proper handling, removal and disposal of farm waste which can reduce production of GHGs like CH4 and CO2.展开更多
This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal co...This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal composting; Scenario 3, sorted waste used for anaerobic digestion; and Scenario 4, sorted waste taken to a composting centre. The results of this study suggest that Scenario 1 would emit the highest levels of GHG （greenhouse gas） emissions, 692 x 103 tonnes CO2eq per year. Scenario 3 would have the lowest levels of GHG emissions, 195 x 103 tonnes CO2eq per year. Compared with the baseline scenario, it yields a 72% reduction of GHG emissions with a total savings of 498 ~ 103 tonnes CO2eq per year. The second-best option is Scenario 2, followed closely by Scenario 4, both yield 66.6% reductions with deviation by 0.03%. The deviation is due to transportation, which emission is negligibly small. The amounts of GHG savings for Scenario 2 and 4 are 461.3 ×10^3 tonnes CO2eq per year and 461×10^3 tonnes CO2eq per year, respectively It is evident from these results that anaerobic digestion has the highest potential for reducing GHG emissions.展开更多
The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of ne...The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of new technologies for waste management such as gasification and melting treatments. The possibility to introduce in the Italian context the DMS （direct melting system） technology, designed and manufactured by Nippon Steel Engineering Co. Ltd., has been taken into account for the scope of proposed work. DMS technology consists in MSW gasification, slags melting and combustion of the syngas produced, with the consequent generation of electric energy through a steam cycle. The system minimizes environmental impact, thanks to an effective recycling of useful resources such as inert melted slags and metals, featuring high flexibility in terms of treatment capacity due to its modular design. The aim of this article is to consider different plant configurations in order to optimize the energy recovery downstream the DMS module. As a case study, landfill gas exploitation integrated in the DMS plant will be considered as a typical situation that could occur in the Italian scenario. The energetic input provided by the biogas allows improving the thermo-economic performances according to market incentives.展开更多
文摘Surface mining operations extract a large quantity of waste material,which is generally disposed into a dump area.This waste can cause a series of environmental problems ranging from landscape deterioration to acidic water generation and water pollution.Therefore,mine waste management is a significant task in mining operations.As known,in strip mining,the overburden is not transported to waste dumps but disposed directly into adjacent strip which was mined out.This concept can be adapted for mine planning of relatively horizontal deposits through a mixed integer programming(MIP)model.The main idea behind this work is that,in one pit,production voids created in early year of mining are used for waste landfilling in late years of production.In other words,in addition to external dumping,a landfilling option within the same pit is proposed for mine design optimization.The problem is formulated as maximization of the net present value(NPV)of the mining project under the constraints of access,landfill waste handling,mining and processing capacities.A case study using a data set was carried out to see the performance of the proposed approach.The findings showed that this approach could be used in waste management incorporating a landfilling option into mine planning.As a result,material handling costs decrease,and environmental compliance increases due to less external waste quantity.
文摘A survey of major chicken meat hatcheries in Australia was undertaken in 2008 to identify how hatchery waste is currently managed. A weekly average of 10.4 tonnes of waste is produced by chicken meat hatcheries. The cost of disposal （average $127/tonne） and availability of disposal sites is an emerging issue. The majority of hatchery waste is sent to land fill or for composting, with some rendered for use as pet food. Hatchery wastewater is mostly used for irrigation or disposed directly into the sewer. Most of the hatcheries have no environmental issues with hatchery waste on site but some report odour problems. Some hatcheries would like to treat the waste on site so that it could be sold as a commodity or to use methods to separate liquid from solid waste and recycle water.
文摘Solid waste management in developing countries has assumed the scale of a major social and environmental challenge. However, many developing countries such as Nigeria have a chronic solid waste management problem. Poorly managed solid waste in market has resulted in health hazards and environmental disaster due to contamination by vermin. This paper studies the management of solid waste in Bodija market, Ibadan, Nigeria. The study adopted a quantitative approach, employing waste composition analysis of samples from the case study area, and questionnaire survey as key methods for data generation. Analysis of result reveals poor collection practise in the market with 6.7% respondents practicing open burning of refuse. However, high rate of waste generation in the market, inconsistency and inefficiency of the private collection agents and lack of funds on the part of the waste management authority has led to this practise. In the next two decades, a total volume of 282,000 m3 of landfill site would be needed for solid waste disposal in the market. The sanitary landfill technique has the potential to reduce environmental health problems created by the existing disposal methods. Hence, cost recovery practises and reconstruction of management capacity are recommended as solutions to the problem.
文摘The most prevalent way of disposing solid waste in most of the developing countries is open dumping which is the easiest and considered to be the cheapest method of removing waste from the immediate environment. The increasing awareness on public health and environment quality concerns are expected to provide the impetus that is needed to develop and implement a sustainable approach to manage solids. An inventory of these locations, the types of waste handled and management processes for waste products will aid in the assessment of the polluting capability of such sites. This paper discusses research experiences gathered during a study that was undertaken in three Kenya dumpsites to explore the potential for utilising the waste for energy generation in a low-income economy and at the same time, address worsening disposal challenges.
文摘Livestock farm waste contributes substantially to annual worldwide emissions of GHG （Greenhouse Gases）, including CH4 （Methane） and CO2 （Carbon Dioxide）. However, despite evidence of global climate change and its adverse health effects, studies on anthropogenic contributions to the increasing levels of GHG, particularly from livestock waste management practices, have not been adequately explored, especially in less developed countries. This study determined waste management practices and outdoor levels of CH4 and CO2 at three selected livestock farms （A-C） in Ibadan, Oyo State, Nigeria. Each study farm consisted of poultry, cattle and pig units. A 30-point observational checklist documented adequacy of solid waste management practices. Ambient concentrations of CH4 and CO2 at farm buildings and at waste disposal sites were monitored every other day, twice each day of monitoring （morning and evening hours）, for eight weeks during months of September-November in 2013. Average scores for the waste management practices for Farms A-C were 29.6%, 33.3% and 18.5%, respectively. Morning and evening CH4 concentrations in parts per million （ppm） at main buildings of Farms A-C were 2,538 ± 773 and 1,916 ± 662, 2,325 ± 773 and 1,180 ± 483, and 2,389 ± 687 and 1,854 ± 571, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C main buildings were 350 ± 130 and 330 ± 110, 470 ± 100 and 440 ± 100, and 430 ± 80 and 400 ± 70, respectively. Morning and evening CH4 concentrations （ppm） at Farms A-C waste disposal sites were 2,452 ± 495 and 1,614 ± 372, 1,527 ± 390 and 1,736 ± 269, and 2,345 ± 615 and 1,690 ± 387, respectively. Morning and evening CO2 concentrations （ppm） at Farms A-C waste disposal sites were 330 ± 90, 370 ± 60 and 350 ± 30, respectively. Waste management practices were inadequate; solid waste management practices like infrequent evacuation of slurry waste and open burning of waste may have contributed to the production of CH4 and CO2. This study suggested proper handling, removal and disposal of farm waste which can reduce production of GHGs like CH4 and CO2.
文摘This study defines and compares four scenarios for MSW （municipal solid waste） management： Scenario 1, unsorted waste taken to a landfill （baseline scenario）; Scenario 2, sorted waste used for home or communal composting; Scenario 3, sorted waste used for anaerobic digestion; and Scenario 4, sorted waste taken to a composting centre. The results of this study suggest that Scenario 1 would emit the highest levels of GHG （greenhouse gas） emissions, 692 x 103 tonnes CO2eq per year. Scenario 3 would have the lowest levels of GHG emissions, 195 x 103 tonnes CO2eq per year. Compared with the baseline scenario, it yields a 72% reduction of GHG emissions with a total savings of 498 ~ 103 tonnes CO2eq per year. The second-best option is Scenario 2, followed closely by Scenario 4, both yield 66.6% reductions with deviation by 0.03%. The deviation is due to transportation, which emission is negligibly small. The amounts of GHG savings for Scenario 2 and 4 are 461.3 ×10^3 tonnes CO2eq per year and 461×10^3 tonnes CO2eq per year, respectively It is evident from these results that anaerobic digestion has the highest potential for reducing GHG emissions.
文摘The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of new technologies for waste management such as gasification and melting treatments. The possibility to introduce in the Italian context the DMS （direct melting system） technology, designed and manufactured by Nippon Steel Engineering Co. Ltd., has been taken into account for the scope of proposed work. DMS technology consists in MSW gasification, slags melting and combustion of the syngas produced, with the consequent generation of electric energy through a steam cycle. The system minimizes environmental impact, thanks to an effective recycling of useful resources such as inert melted slags and metals, featuring high flexibility in terms of treatment capacity due to its modular design. The aim of this article is to consider different plant configurations in order to optimize the energy recovery downstream the DMS module. As a case study, landfill gas exploitation integrated in the DMS plant will be considered as a typical situation that could occur in the Italian scenario. The energetic input provided by the biogas allows improving the thermo-economic performances according to market incentives.
