Typical Municipal Solid Waste Research Articles

Exergoeconomic valuation of a waste-based integrated combined cycle (WICC) for heat and power production

Exergy and exergoeconomics assessment tools were applied to a municipal solid waste (MSW) gasification system integrated with a combined cycle (WICC). The techno-economic feasibility of the system was studied using a typical MSW produced in southern Chile and a combined experimental-modeling approach. Results suggested that gasifier should operate between 850 °C and 950 °C, in order to produce a syngas with the required energy content (LHV>3 MJ/kg) to feed power and steam cycles. Operation at lower temperatures and equivalence ratios, reduced the exergy efficiencies (<49%) due to the low carbon conversion, syngas composition and to the low heat recovery potential of exhausted gas. Exergy losses at gasifier amounted nearly 60% of the whole system due to the effect of chemical reactions and heat transfer in this stage. Above 850 °C, the total production cost (Ctot), exergy destruction cost (CD) and environmental cost (Cenv) were reduced, leading to a positive economic framework. The thermoeconomic cost of electricity (TCOE) using MSW as feedstock varied between 0.07 and 0.13 US$ kWh−1, which is competitive with the electricity price in the Chilean market (0.12 US$ kWh−1).

Mini-review of the geotechnical parameters of municipal solid waste: Mechanical and biological pre-treated versus raw untreated waste.

The most viable option for biostabilisation of old sanitary landfills, filled with raw municipal solid waste, is the so-called bioreactor landfill. Even today, bioreactor landfills are viable options in many economically developing countries. However, in order to reduce the biodegradable component of landfilled waste, mechanical and biological treatment has become a widely accepted waste treatment technology, especially in more prosperous countries. Given that mechanical and biological treatment alters the geotechnical properties of raw waste material, the design of sanitary landfills which accepts mechanically and biologically treated waste, should be carried out with a distinct set of geotechnical parameters. However, under the assumption that 'waste is waste', some design engineers might be tempted to use geotechnical parameters of untreated raw municipal solid waste and mechanical and biological pre-treated municipal solid waste interchangeably. Therefore, to provide guidelines for use and to provide an aggregated source of this information, this mini-review provides comparisons of geotechnical parameters of mechanical and biological pre-treated waste and raw untreated waste at various decomposition stages. This comparison reveals reasonable correlations between the hydraulic conductivity values of untreated and mechanical and biological pre-treated municipal solid waste. It is recognised that particle size might have a significant influence on the hydraulic conductivity of both municipal solid waste types. However, the compression ratios and shear strengths of untreated and pre-treated municipal solid waste do not show such strong correlations. Furthermore, another emerging topic that requires appropriate attention is the recovery of resources that are embedded in old landfills. Therefore, the presented results provide a valuable tool for engineers designing landfills for mechanical and biological pre-treated waste or bioreactor landfills for untreated raw waste as well as planning landfill mining projects.

Emerging Waste-to-Energy Technologies: Solid Waste Solution or Dead End?

Incineration is a dirty word in the United States, at least where trash is involved. We’ve been burning municipal solid waste (MSW) since the 1880s. But the dawning of the environmental movement eight decades later cast new light on the nitrous oxides, dioxins, and other chemicals emitted from as many as 600 mass-burn incinerators nationwide, which meanwhile had also grown in size. 1 , 2 The ecological merits of resource conservation and recycling became another area of growing interest. Three emerging thermal waste-to-energy technologies seek to turn municipal solid waste from a burden to an asset. Adherents of these technologies say they produce fewer toxic emissions and virtually eliminate landfilling. But none of the technologies ... Now three new approaches to converting trash into energy—so-called waste-to-energy (WTE) technologies—look to leave mass-burn incineration behind by transforming how we think about MSW in the United States. Adherents of these emerging approaches—gasification, plasma gasification, and pyrolysis—promise cleaner emissions and more flexibility in terms of energy output, plus in some cases the virtual elimination of landfilling through a complex two-stage treatment process. 3 , 4 , 5 , 6 , 7 But none of the technologies have yet been proven on a commercial scale on U.S. soil using a typical mixed MSW feedstock, says Monica Wilson, program director for the advocacy group Global Alliance for Incinerator Alternatives (GAIA). After years of delays and high-profile failures, the technologies remain stymied by challenges such as operational inexperience, high costs, lack of financing, and concerns about toxic emissions. Furthermore, the heterogeneous nature of MSW can make it a problematic feedstock for power plants, and some critics believe it is more important to assess what materials are actually in MSW and the best uses associated with each of those materials—for instance, recycling, composting, reducing, or redesigning the materials before they enter the waste stream. Negative public perception of incineration also could prevent acceptance of newer WTE technologies in the United States. Modern mass-burn facilities are a huge improvement over the dirty plants that first drew public outrage. Beginning with the Clean Air Act in 1970, tightened regulations and sophisticated air pollution controls significantly reduced the levels of harmful chemicals emitted by incinerators. Today, 70 mass-burn plants in 21 states 8 consume about 13% of the nation’s trash, down from a peak of 14.5% in 1990. 9 , 10 Cumulatively they offer roughly 2.5 gigawatts of power in return, 11 , 12 less than a tenth of what the U.S. solar industry produces. 13 The most recent inventory available from the U.S. Environmental Protection Agency shows that MSW incinerators released about 1% of the quantity of carcinogenic and highly toxic dioxin-like compounds in 2000 that they did just 13 years earlier. 14 Yet by the 1980s the damage to incineration’s reputation was done, as far as many environmental groups and the public at large were concerned. And the battle lines drawn all those years ago remain largely intact today. So claims that these new technologies offer a panacea to waste management and a source of clean, renewable energy have met with skepticism and organized opposition in dozens of communities nationwide faced with proposals in recent years. 15 Ultimately, if the new technologies are to take hold in this country, developers must find a way to not only support their performance claims, but also demonstrate compatibility with established recycling and composting efforts and achieve financial feasibility in areas experiencing no shortage of landfill space. 16 Even some proponents of the new technologies wonder if that will ever happen.

Review of Typical Municipal Solid Waste Disposal Status and Energy Technology

The physical and chemical components of urban domestic waste, medical waste and electronic waste are introduced, the advantages and disadvantages of the existing processing methods are pointed out. Considering the higher content of organic and metal of these municipal solid wastes, pyrolysis technology is a suitable method to make them harmless, reduced, reusable and being available energy.

Effect of Operating Parameters and Moisture Content on Municipal Solid Waste Pyrolysis and Gasification

Pyrolysis/gasification-based waste-to-energy (WtE) techniques, comprising partial oxidation of waste and subsequent syngas combustion, show potential benefits over direct incineration. To facilitate their development under the specific conditions of China, pyrolysis and gasification of typical municipal solid waste (MSW) are investigated in a fluidized bed reactor. The effect of the equivalence ratio (ER), reaction temperature, and moisture content on MSW conversion is studied. A rising ER increases the syngas yield but decreases the syngas heating value. The combustible gas yield is strengthened at lower ERs and later drops when the ER exceeds 0.4 as a result of the continuously enhanced oxidation reactions. A higher temperature favors pyrolysis reactions but causes an evident decrease in the syngas heating value during gasification. When the ER is at 0.4 and the temperature is at 650 °C, an optimum operating performance is obtained under the specific input simulated MSW (S-MSW) and test conditions, with...

The application of prepared porous carbon materials: Effect of different components on the heavy metal adsorption.

In this study, five typical municipal solid waste (MSW) components (tyres, cardboard, polyvinyl chloride (PVC), acrylic textile, toilet paper) were used as raw materials to prepare four kinds of MSW-based carbon materials (paperboard-based carbon materials (AC1); the tyres and paperboard-based carbon materials (AC2); the tyres, paperboard and PVC-based carbon materials (AC3); the tyres, paperboard, toilet paper, PVC and acrylic textile-based carbon materials (AC4)) by the KOH activation method. The characteristic results illustrate that the prepared carbon adsorbents exhibited a large pore volume, high surface area and sufficient oxygen functional groups. Furthermore, the application of AC1, AC2, AC3, AC4 on different heavy metal (Cu(2+), Zn(2+), Pb(2+), Cr(3+)) removals was explored to investigate their adsorption properties. The effects of reaction time, pH, temperature and adsorbent dosage on the adsorption capability of heavy metals were investigated. Comparisons of heavy metal adsorption on carbon of different components were carried out. Among the four samples, AC1 exhibits the highest adsorption capacity for Cu(2+); the highest adsorption capacities of Pb(2+) and Zn(2+) are obtained for AC2; that of Cr(3+) are obtained for AC4. In addition, the carbon materials exhibit better adsorption capability of Cu(2+) and Pb(2+) than the other two kind of metal ions (Zn(2+) and Cr(3+)).

Opportunities & Challenges in Capturing Landfill Gas from an Active and Un-scientifically Managed Land Fill Site – A Case Study

Currently, nearly 210 Million Metric Tonnes/Annum of Municipal Solid Waste (MSW) is generated in India and most of it gets disposed in Open and un-scientifically managed Landfills. The typical Indian MSW contains approximately 50% of bio-degradable organic components that starts degrading under anaerobic conditions and generates LandFill Gas (LFG). The LFG mainly contains Methane (40-50%) and CO2 (50-60%). Methane is a Green House Gas (GHG), and is 25 times more potent than CO2 in causing Global Warming and is the 2nd largest anthropogenic source of Methane emissions after coal mining. Thus capturing and destructions of LFG shall lead to mitigation of GHG emissions. In addition, open Landfill sites also pose safety risks like fire hazard, explosion, and asphyxiation etc. apart from health risks.At the current MSW generation rate of 0.575MMT/day in India, the LFG generation potential is around 86.25 MMSCMD of LFG. Presently, LFG from the landfill sites is not being captured leading to fugitive GHG emissions. Further, due to rapid population growth and accompanying urbanisation and lack of new landfill sites, the existing waste handling infrastructure is getting stressed and leading to overflowing and vertical growth of the existing landfills. Thus Indian landfills provide good opportunities for the extraction & utilisation of Methane from LFG. However, there are lot of Issues that need to be overcome for exploitation of LFG in a sustainable manner.GAIL (India) Ltd, a Maharatna company, as a part of its R&D activities has taken up an initiative in this direction and implemented a Pilot project to ascertain the recovery of LFG from an un-scientifically managed open active MSW dumping site at Ghazipur Delhi. The utilization of LFG for energy recovery is being explored. This Paper shares the Challenges faced and Key insights gained during the LFG Project Implementation and its Operation.

Environmental Friendly Ways to Generate Renewable Energy from Municipal Solid Waste

Economic growth and rapid urbanization are resulting into increase in generation of municipal solid waste (MSW). In India, approximately 68 MT of MSW generated annually in urban areas and more than 80% is disposed in unhygienic manner leading to problems of health and environment to inhabitants. To manage MSW, there is a need to plan infrastructure development. There are many technologies available for handling MSW which treat plastic to convert fuel oil by gasification, pyrolysis, biomethanation and catalytic conversions. The useful products like liquid fuels, chemicals and power are being generated through these processes.The final products need to comply with environmental regulations and demand a lot of technological improvement. Based on MSW/feed quality, there is a need to identify the suitable technology for converting MSW into useful products, which can meet the statuary regulations. Hence, treating MSW, converting into useful products and selection of suitable technology is a big challenge.The present paper focuses to compare:•All suitable treatment technologies and products generated from MSW.•Types of thermal treatments like combustion/incineration, gasification and pyrolysis.It also highlights development of a systematic approach to comply with all environmental regulations to create value for all types of MSW and reduce landfill.

Biodrying Process Efficiency: -Significance of Reactor Matrix Height

Waste to energy concept should become a reality to meet the critical issues faced by the solid waste management system of developing nations. Energy oriented municipal solid waste conversion technologies have the potential to reduce the bulk volume of the waste in addition to the refuse derived fuel production applications. In this scenario biodrying process is found to be the best option, where biological heat energy is effectively channelized for drying purpose so that the heavy moisture laden municipal solid waste is dried and its energy value is increased. This technology seemed to be promising specially in the case of developing nations where the heavy moisture content of the typical municipal solid waste is the major issue faced by the waste to energy conversion systems. In the present case study the effect of increasing the reactor matrix height and the resulting changes in the biodrying process output has been studied in a pilot scale biodrying reactor of 0.565 m3 capacity for a period of 10 days. Two case studies were conducted on mixed municipal solid waste substrates with moisture content of 62.45% and 66.4% respectively. The reactor matrix height of first case study was kept at1.65 m, while that is increased to 2.0 m in the second case study. The constant air flow rate of 40 litre per minute was provided throughout the experiment for both case studies. During the second case study an air evacuation test has also been conducted on the 4th and 5th day of experiment to understand the temperature profile variations. Overall weight reduction of 26.32% and 19.01% along with average moisture reduction of 24.26% and 15.98% has been achieved in the first and second case studies respectively in 10 days of reaction. The volume reduction and bulk density increase was the maximum in the second case study with 43.5% volume reduction and 53.01% bulk density increase in achieved in 10 days of biodrying reaction. Comparing to that a lesser result has been obtained in 10 days of experiment in the first case study with a volume reduction of 35.1% and bulk density increase of 27.58%. Therefore increasing the reactor matrix height at a constant air flow rate has affected the biodrying process efficiency in terms of weight reduction and moisture reduction, but the volume reduction and bulk density increase were significant achievements.

THE EMISSION POTENTIAL FROM MUNICIPAL SOLID WASTE LANDFILL IN JORDAN

A comprehensive study was conducted to monitor the emission potential from solid waste landfilled in Jordan over a period of 292 days using an anaerobic lysimeter. A 30 kg waste sample reflecting the typical municipal solid waste (MSW) streams generated in Jordan was used to simulate the influence of climate on the emission potential of landfills located in semi-arid areas. The experimental results demonstrated that a significant amount of leachate and landfill gas was produced. The methane content was found to be more than 45% and the leachate produced reached 15.7 l after 200 days. However, after 260 days the gas and leachate production rate became negligible. A significant amount of heavy metal traces was found in the leachate due to mixed waste disposal. Changes in biogas and leachate quality parameters in the lysimeter revealed typical landfill behaviour trends, the only difference being that they developed much more quickly. In view of current landfill practices in Jordan and the effect of climate change, the results suggest that landfill design and operational modes need to be adjusted in order to achieve sustainability. For this reason, optimized design parameters and operational scenarios for sustainable landfill based on the country’s climatic conditions and financial as well as technical potential are recommended as a primary reference for future landfills in Jordan as well as in similar regions and climates. (Less)

Characterization of odor emission on the working face of landfill and establishing of odorous compounds index

Temporal variation (seasonal and daily) of odor emission on the working face of a large sanitary landfill in China was characterized through a 2 yearlong case study. Odor pollution was most serious in spring and autumn, while lower odor concentrations were detected in summer and winter. The daily fluctuation of odor concentration on the working face showed that 2:00am, 6:00am, 2:00pm and 10:00pm were the “most probable times” for odor pollution occurrence, which deserves focused attention in odor control projects. Correlations analysis found that 41% of the variance in odor concentrations can be explained by the chemical concentrations of odorous compounds.Moreover, the selection criteria for the index of odorous compounds were also established by evaluating the odor concentration, contribution to odor strength and the frequency of each compound present in all the samples. Ethyl alcohol, α-piene, hydrogen sulfide, dimethyl sulfide, limonene, methyl mercaptan, dimethyl disulfide, and diethyl sulfide comprise the index of odorous compounds on the working face of typical municipal solid waste landfill in China.

Thermogravimetric characteristics of typical municipal solid waste fractions during co-pyrolysis

The interactions of nine typical municipal solid waste (MSW) fractions during pyrolysis were investigated using the thermogravimetric analyzer (TGA). To compare the mixture results with the calculation results of superposition of single fractions quantitatively, TG overlap ratio was introduced. There were strong interactions between orange peel and rice (overlap ratio 0.9736), and rice and poplar wood (overlap ratio 0.9774). The interactions of mixture experiments postponed the peak and lowered the peak value. Intense interactions between PVC and rice, poplar wood, tissue paper, wool, terylene, and rubber powder during co-pyrolysis were observed, and the pyrolysis at low temperature was usually promoted. The residue yield was increased when PVC was blended with rice, poplar wood, tissue paper, or rubber powder; while the residue yield was decreased when PVC was blended with wool.

Municipal solid waste (MSW) as a source of renewable energy in Bangladesh: Revisited

Abstract With radically increased population, rapid economic growth and expansion of urbanization and industrialization, mega-cities of Bangladesh are faces the complexity of municipal solid waste (MSW) management. The purpose of this paper is to review the types of MSW that are currently being used for renewable energy sources. To meet up the power supply for city dwellers and reducing space for new landfills, waste-to-energy (WTE) incineration is playing a vital role for renewable energy production from discarded MSW. Incineration of MSW is complex owing to its low calorific value (~3000 kJ/kg) and high water content (~60%). MSW in Bangladesh contains relatively high proportion of organic matter (74.6%) than paper (9.1%) and plastic (3.5%). Using landfill gas recovery process, generation of electricity from MSW in six mega-cities is ~186,408 kW h/day. Therefore, WTE incineration system contributes greater supply of renewable energy in Bangladesh.

Dioxin formation and control in a gasification-melting plant.

We investigated dioxin formation and removal in a commercial thermal waste treatment plant employing a gasification and melting process that has become widespread in the last decade in Japan. The aim was to clarify the possibility of dioxin formation in a process operation at high temperatures and the applicability of catalytic decomposition of dioxins. Also, the possible use of dioxin surrogate compounds for plant monitoring was further evaluated. The main test parameter was the influence of changes in the amount and type of municipal solid waste (MSW) supplied to the thermal waste treatment plant which from day to day operation is a relevant parameter also from commercial perspective. Here especially, the plastic content on dioxin release was assessed. The following conclusions were reached: (1) disturbance of combustion by adding plastic waste above the capability of the system resulted in a considerable increase in dioxin content of the flue gas at the inlet of the bag house and (2) bag filter equipment incorporating a catalytic filter effectively reduced the gaseous dioxin content below the standard of 0.1 ng toxic equivalency (TEQ)/m(3) N, by decomposition and partly adsorption, as was revealed by total dioxin mass balance and an increased levels in the fly ash. Also, the possible use of organohalogen compounds as dioxin surrogate compounds for plant monitoring was further evaluated. The levels of these surrogates did not exceed values corresponding to 0.1 ng TEQ/m(3) N dioxins established from former tests. This further substantiated that surrogate measurement therefore can well reflect dioxin levels.

Concentration and distribution of PCNs in ambient soil of a municipal solid waste incinerator

The impact of a typical municipal solid waste incinerator (MSWI) on polychlorinated naphthalene (PCN) concentrations in surrounding soil was studied. We collected 6 stack gas samples from the MSWI and 21 soil samples from sampling sites at distances of between 300 and 1700m from the MSWI stack. Total dl-PCN (dioxin-like PCN) concentrations in the stack gas samples ranged from 6898 and 89,032pgm−3, with a mean value of 36,241pgm−3. The total dl-PCN concentrations in the soil samples ranged from 30.35 to 280.9pgg−1, with a mean value of 87.03 and a median value of 70.32pgg−1, while the TEQ values were between 7.7 and 130.2fg TEQ g−1, with a mean value of 41.12fg TEQ g−1 and a median value of 31.52fg TEQ g−1. The PCN homologue patterns and the results of Principal Component Analysis suggested that the MSWI may be a source of PCNs in the soils. A contour map, created using an ordinary Kriging interpolation technique, showed that a limited area (≤1000m radius) surrounding the MSWI was influenced by the emissions from the MSWI. Furthermore, an exponential function equation was proposed to quantify the relationship between TEQs of PCNs and the distance from the stack.

Household Solid Waste Management Methods in Lafia, Nasarawa State Nigeria

The study discusses the socio-economic characteristics of household heads, types of waste generated and methods of disposal by household heads in Lafia. The study area was divided into three high, medium and low densities in terms of development. This was largely based on the data gathered through administration of questionnaire using systematic sampling methods. 270 copies of questionnaire were administered to household heads in the three areas selected, where high density area has 98; medium density area has 90 while low density area has 82 respectively. It was deduced that all the major types of municipal solid waste are generated in all the areas, and majority of household heads in the three areas use either plastic or metal buckets to collect and disposed their waste and also that the socio-economic characteristics varied in all the three areas at 5% probability level as 0.842 5.99, this shows that solid waste is more of a problem in the high density area than in the medium and low density areas.

Mechanical biological treatment for municipal solid waste

A major portion of municipal solid waste (MSW) is dumped in unsanitary landfills in India. To protect the environment, there is an urgent need to develop a technology which could handle the increasing MSW quantities and enhance resource recovery. Mechanical biological treatment (MBT) is considered a potential method for dealing with heterogenous MSW. Proper mechanical sorting can make the post-treatment (biological as well as thermal processes) much effective. In the manuscript, MSW sorting options for the eight most populous cities in India are evaluated using simplified material flow analysis. The analysis highlights that ~45–97% of the total MSW can be diverted from landfills by using the proposed schemes. Some alterations in the current waste collection and segregation practices can maximise the benefits from MBT process. The reported study is beneficial for waste managers dealing with similar type of MSW.

Towards the estimation of demand for recycling in Chile: The case of Santiago

In developing countries, the recycling of municipal solid waste (MSW) as an alternative to the traditional MSW management requires an economic sustainability valuation. From this perspective, the estimation of demand for recycling is crucial. In this paper, we study the case of recycling MSW in Santiago, Chile. We estimate the relation between the monthly amount of MSW separated voluntarily from apartments located in Santiago and the monthly price required to participate in a municipal recycling program. We consider the transference of the municipal cost savings to the owners of the apartments due to the amount of MSW separated for recycling, which is not collected and deposited in the current MSW system. For the estimation, we use concepts from environmental economics and psychology, analyzing the operation and municipal costs incurred by current MSW management and designing and applying a survey based on a contingent valuation method (CVM) approach. The results indicate that the percentage of MSW separated for recycling varies between a 27.98% and 33.18%, that only four MSW types are affected by a variation of the monthly price, and that a reduction of monthly collection trips in the current MSW system from 24 to 18 can be obtained. Additionally, we discuss a number of methodological aspects to be considered in a similar study of valuation of recycling in developing countries. Our conclusion is that Santiago has favorable conditions for the implementation of a recycling program as an alternative to the current MSW system.

Feasibility of Recovering Energy from Municipal Solid Waste to Generate Electricity

Population growth and economic development in Indonesia have increased the production of municipal solid waste ( MSW) in many big cities, causing sanitary problems. The (MSW) disposal problem can be solved by applying an appropriate technology that can reduce the volume of the waste effectively and efficiently. Waste-to-Energy (WTE), or Energy-from-Waste (EFW), is one of the most effective and efficient t echnologies for reducing the waste volume. Energy recovered from the waste can be used for thermal or electricity generation. This paper deals with a fea sibility study of utilizing MSW for generating electricity. A survey and investigat ion of waste characteristics, including waste composition, chemical and physical composition, and heating value, were carried out for typical Bandung MSW. An average heating value of 1500 kcal/kg can be expected from pre-treated MSW to be used as a fuel for direct combustion in a WTE plant. A typical design for a small-scale WTE plant is shown in this paper and also an energy analysis is provided. Approximately 800 kW of electric power can be generated from 50 t onnes of MSW per day.

Spatial distribution of polychlorinated biphenyls in soil around a municipal solid waste incinerator

The impact of a typical municipal solid waste incinerator (MSWI) on polychlorinated biphenyl (PCB) concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total (PCB) concentrations of dioxin-like (dl) PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents (TEQs) ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The PCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in PCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area (≤ 1250 m radius) from the stack was clearly influenced by PCB emission from the MSWI.