Volume 28, 2002

Issue 4, November 2002



F. J. Aguilar

Departamento de Ingenier�a Rural

Universidad de Almer�a. La Ca�ada de San Urbano

04120 Almer�a, SPAIN

Email: faguilar@ual.es

P. Gonz�lez

Centro de Investigaci�n y Formaci�n Agraria

Departamento de Suelos y Riegos

14080 C�rdoba, SPAIN


  This work studies the effects produced on some soil physical properties by a new soil management system in rainfed olive groves. The assay was made in an experimental plot located in C�rdoba (South Spain). This consisted of a periodic application, in principle approximately every three years, of organic matter in the form of compost from municipal solid waste (MSW) and its incorporation by means of ploughing on the topsoil (horizon of 0-5 cm). The grove was maintained with non-tillage and the soil bare. The objective was to recycle the organic matter contained in MSW, maintaining the advantages with respect to erosion reduction and water conservation in the soil produced by a non-tillage bare soil management system in Mediterranean olive groves. At the same time we tried to rectify the serious problems of the formation of a laminar crust on the topsoil. This system’s comparison with other management systems, such as conventional tillage or non-tillage with bare soil, has shown a greater infiltration and availability of water for trees due to a decline in the bulk density and an increase of saturated hydraulic conductivity and macroporosity. The stabilization of the topsoil horizon, by means of the system proposed, permits this situation to continue for at least two or three years, unlike what occurs in conventional tillage or minimum tillage, in which, in most cases, the effects of tillage are provisional.

Key Words: Compost, Municipal Solid Waste, Soil Physical Properties, Olive Groves, Soil Management Systems

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Chi-Wai Hui, John Porter and Gordon McKay

Chemical Engineering Department

Hong Kong University of Science and Technology

Clear Water Bay, HONG KONG

Raymond Cheung and Peter Leung

Green Island Cement Company Limited

No. 7, Lung Yiu Steet

Tap Shek Kok

Tuen Mun, N.T. HONG KONG


This paper presents a novel and highly integrated design of cement and electricity production by co-combustion of municipal solid waste (MSW) and fuel. By tightly integrating the three processes, energy generated from the co-combustion can be effectively utilized for cement production and electricity generation. This synergy also results in significant reduction in new pollutant emissions. Solid wastes such as fly ash from the combustion can be used as feedstock for cement production. The raw material of cement production such as lime (CaO) works as an adsorbent for converting polluting gas such as SOx generated from the combustion to components of cement such as calcium sulfate (CaSO4). The reduction of chlorine compounds in the combustion process plays a key role in managing dioxin formation from the combustion process. Lime again is good adsorbent for chloride to prevent it from being converted into dioxin during the high temperature process. Using the heat generated from the combustion process, wooden wastes sorted from MSW can be converted into active carbon that is a ideal adsorbent for dioxin in the downstream air pollution control processes of the waste gases. The large amount of lime used in cement production and the low-cost active carbon cleanup the waste gases in the most economic and effective way. These three processes are perfectly integrated reducing overall energy consumption and pollution. An integrated pilot unit is being built in Hong Kong and will be ready for operation by the end of year 2002.

Key Words: MSW management, Cement Production, Plant Integration

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R. Bellizia

RMIT University

Melbourne, Victoria, AUSTRALIA

P.R. Thomas

La Trobe University

Wodonga, Victoria, AUSTRALIA

I. Patnaikuni

RMIT University

Melbourne, Victoria, AUSTRALIA


Changes from pasture grazing to feedlot systems have provided great benefits to the beef cattle industry, creating a large amount of waste to be managed in a limited area of land. This poses an environmental management problem to the owners. To manage the waste effectively, incineration of the manure at an appropriate temperature is a viable option because it not only reduces pollution, but it also produces ash, which could be used in the construction industry. Cattle manure was subjected to different temperatures and durations, and an optimum temperature of 600�C of 2-hour duration was chosen. The properties of the cattle waste ash produced, as well as its effects of using it as a partial cement replacement in concrete and mortar mixes were evaluated in terms of compressive strength and drying shrinkage. It was observed that for an increase in waste ash content there was a general decrease in compressive strength for all concrete mixes and most of the mortar mixes. However, a slight increase in strength with time was noted for mortar samples with a low proportion of cattle waste ash content.

Key Words: Cattle waste ash, pozzolanic, concrete, mortar, compressive strength, drying shrinkage, fineness, binder

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Alexandra Bruinsma

Jens Neugebauer

Markus Hiebel

Kai Keldenich

Hans Fahlenkamp

Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT

Osterfelder Str. 3, D-46047 Oberhausen


Email: bral@umsicht.fhg.de


Over the last years, the German waste management system has reached a remarkable and internationally accepted level concerning technological and ecological aspects. Municipal solid waste incineration facilities play an important role on the waste market. Nevertheless, these installations are under considerable economic pressure due to changing environmental standards and due to market changes initiated by legislation. Therefore, it is necessary to perform a continuous identification of internal weak points in the operational processes to reach a sustainable leading position on the market. There are, however, different methods to optimize technical processes economically and ecologically like material flow analyses, various waste management systems, eco-controlling and hazard- and life cycle analyses. This paper investigates the method of benchmarking as an integrative approach to identify operational weak points on the basis of a sector-wide comparison of technical parameters. The consequent benchmarking process helps to show alternatives with respect to operational, economic and ecological aspects. These alternatives can be used by the plant operators to compare and to optimize their plants e.g. in terms of economic efficiency.

Key Words: Benchmarking, plant optimization, waste incineration, best available technology, indicators

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Economic and Environmental Optimization of Integrated Solid Waste Systems

M. El-Fadel and M. Abou Najm

American University of Beirut, Faculty of Engineering and Architecture

Bliss Street, P.O. Box 11-0236, Beirut, LEBANON

Fax: 961-1-744 462, Email: mfadel@aub.edu.lb


Increased environmental concerns and the emphasis on material and energy recovery are gradually changing the orientation of MSW management and planning. In this context, the application of optimization techniques has been introduced to design the least cost solid waste management systems, considering the variety of management processes (recycling, composting, anaerobic digestion, incineration, and landfilling), and the existence of uncertainties associated with the number of system components and their interrelations. This study presents a model that was developed and applied to serve as a solid waste decision support system for MSW management taking into account both socio-economic and environmental considerations. The model accounts for solid waste generation rates, composition, collection, treatment, disposal as well as potential environmental impacts of various MSW management techniques. The model follows a linear programming formulation with the framework of dynamic optimization. The model can serve as a tool to evaluate various MSW management alternatives and obtain the optimal combination of technologies for the handling, treatment and disposal of MSW in an economic and environmentally sustainable way.

Key Words: Integrated solid waste management, linear programming, optimization

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K. Lee(1), Y. Yoon(2), J. Cho(3), R. Salgado(4) , I. Lee(5) , N. Kim(6)

(1) Assistant Professor, Dept. of Civil Engineering

Kyungsung University, Pusan, KOREA

(2) Engineer, Chung-Suk Engineering Co., Ltd.

Seoul, KOREA

(3) Professor, Dept. of Civil Engineering

Dongui University, Pusan, KOREA

(4) Associate Professor, School. of Civil Engineering

Purdue University, W. Lafayette, IN 47907, USA

(5) Professor, Dept. of Civil and Environmental Engineering

Korea University, Seoul, KOREA

(6) Assistant Professor, Dept. of Architectural Engineering

Korea University of Technology and Education, KOREA


The purpose of this paper is to present values of engineering properties of co-mixtures of fly ash and Waste Foundry Sand (WFS), which are presently used as fill or flowable backfill. The class-F fly ash generated at the Tae-An thermoelectric power plant was used in the testing program. Green sand, Furane sand, and Coated sand, which had been used at a foundry located in Pusan, Korea, were the sands used in the testing program. Laboratory experiments were performed to obtain the physical properties of the co-mixtures of fly ash and WFS. The hydraulic conductivity of the co-mixtures ranged from 3.0*10-5 m/s to 6.0*10-5 m/s. The 7-day unconfined strength of specimen prepared with Green WFS as high as 94% of the 28-day strength, but for specimen prepared with Furane WFS and Coated WFS, this ratio was only 64% and 66% of the 28-day strength, respectively. Results of the consolidated-undrained triaxial tests showed that the co-mixture of Furane WFS showed a distinct increase of the internal friction angle, while the other co-mixtures showed negligible increase. In the case of 28-day cured specimens, specimens of Furane WFS showed an internal friction angle of 41.8o, while specimens of Green and Coated WFS showed those of 33.5o and 35.0o, respectively. From the shrinkage test, the shrinkage ratios of all specimens did not exceed 0.25%.

Key Words: Controlled low-strength material(CLSM), fly-ash, flowable backfill, waste foundry sand

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Issue 3, August 2002

Sewage Sludge Ash As Use Of Fine Aggregate And Pozzolan In Portland Cement Mortar

Dyi-Hwa Tseng, Shih-Cheng Pan
Graduate Institute of Environmental Engineering

Chau Lee
Department of Civil Engineering

National Central University
Chungli, Taiwan 32054


In order to verify the effect of sewage sludge ash (SSA) in cement mortar, this study used SSA as fine aggregate and pozzolan to replace mortar aggregate and portland cement respectively. Both SSA mortars were prepared at replacement ratios of 5~50%. The fly ash mortar was also prepared for comparing the performance of cement replacement. The workability, compressive strength, and capillary pore volume of all mortars were determined. The results revealed that the workability and compressive strength of SSA mortar dramatically decreased with increasing replacement ratio of fine aggregate. The fact of this phenomenon was primarily due to the water-adsorption capability and poor mechanical properties of SSA. Nevertheless, the instinct pores of SSA also affected the compressive strength of mortar. Thus, the coarse SSA was a poor aggregate for cement mortar. On the other hand, using finely ground SSA to replace mortar cement also exhibited workability and compressive strength reduction owing to the water-adsorption capability and weak pozzolanic activity of SSA. However, when cement replacement ratio was less than 20%, SSA showed similar performance as fly ash in mortar. According to that, the finely ground SSA can be used as pozzolan in mortar when below certain replacement ratio.

Key Words: sewage sludge ash; cement mortar; fine aggregate; pozzolan; pozzolanic activity; workability

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An Innovative Approach To Landfill Gas Profiling And Extraction

Reg P. Renaud, President
STI Engineering
P.O. Box 792
Silverado, California 92676

Michael L. Leonard, Sr., P.E., Senior Associate Engineer
Petra Geotechnical, Inc.
3185-A Airway Avenue
Costa Mesa, California 92626


This paper describes an innovative method to assist landfill owner/operators in keeping their landfill(s) in compliance with regulatory requirements regarding landfill gas emissions and subsurface migration. The in situ method (3-D Landfill Gas Profiling) described, is used to identify areas in a landfill that contain gas pressure, liquid head pressure and vacuum zones. Interpretations of the acquired data can also locate low-density layers of refuse and high-density layers/daily cover layers that can be liquid bearing and/or trap gas. The method can also be used to verify the vacuum from existing collectors. The piezo-penetrometer test (PPT) is used to obtain the in situ data. These data are inputted into a computer CADD system to create a 3-D Landfill Gas Profile (see Figure 1). This paper also describes the design (using the in situ data) and installation of 2-inch diameter push-in steel collectors and Internal Conduits.

Key Words: landfill gas, regulatory compliance, piezo-penetrometer, gas pressure, vacuum, collectors

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A New Approach To Study Leaching Of Fly Ash From Landfills

Devendra N. Singh, Prabir K. Kolay and Anoop K. Rao
Department of Civil Engineering
Indian Institute of Technology
Bombay, Powai, Mumbai-400076, INDIA


Increasing production of fly ash, from the coal based thermal power plants, is posing a challenging problem in terms of its safe disposal and proper utilization. One of the most attractive utilization options of the ash is using it as a landfill material. However, fluctuating water table and rainwater interacts with the fly ash, in the landfills, and results in leaching of toxic heavy metals or trace elements present in it. In the due course of time, this causes contamination of the subsurface soil and the ground water. As such, it becomes mandatory to characterize the fly ash along with identification of its leaching characteristics, for adoption of an efficient disposal strategy. The paper deals with details of new sequential batch leaching tests, which simulate leaching of fly ash from the landfills, as a result of continuous dumping of the ash.

Key Words: Fly ash, characterization, leaching, heavy metals, trace elements, landfill, sequential batch tests

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Engineering Properties Of Wastewater Treatment Sludge Modified By Hydrated Lime And Fly Ash

K. Lee(1), J. Cho(2), R. Salgado(3) , W. Jeon(4), N. Kim(5)
(1) Assistant Professor, Dept. of Civil Engineering
Kyungsung Univ., Pusan, Korea

(2) Professor, Dept. of Civil Engineering
Dongui Institute of Technology, Pusan, Korea

(3) Associate Professor, School of Civil Engineering
Purdue University, W. Lafayette, IN, USA

(4) Engineer, Dodam Engineering Co., Ltd., Seoul, Korea

(5) Assistant Professor, Dept. of Architectural Engineering
Korea University of Technology and Education, Korea


This paper presents experimental results concerning the engineering properties of modified sludge from wastewater treatment using hydrated lime and fly ash. The proper mixing ratio was determined as the ratio required to keep the pH of the modified sludge above 12.0 for 2 hours. Extensive laboratory tests were carried out, including particle size analysis, compaction and CBR tests, SEM, unconfined compression tests, permeability tests, and TCLP tests. Although the main function of lime is to sterilize microorganisms in the sludge, it has an effect on mechanical properties as well. The unconfined compressive strength of the sludge modified by fly ash and lime was found to satisfy the criteria for landfill cover soil, which requires a value above 0.1 MPa. The hydraulic conductivity of all the mixtures was approximately 10-7 cm/sec. Extraction tests revealed the modified sludge to contain quantities of cadmium, copper, and lead. Judging from the extensive testing presented here, the use of fly ash and hydrated lime to modify or stabilize wastewater treatment sludge would be an interesting way to transform this waste material into a usable construction material.

Key Words: Sludge, hydrated lime, fly ash, strength, SEM, permeability, TCLP

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Solid Waste Collection Health And Safety Risks— Survey Of Municipal Solid Waste Collectors

Jeffrey Rogers, James Englehardt, Huren An
Department of Civil, Architectural and Environmental Engineering
University of Miami, Coral Gables, Florida, USA

Lora Fleming
Department of Epidimiology and Public Health,
University of Miami School of Medicine, Miami, Florida, USA


The results of a survey of garbage collectors regarding health and safety aspects of their jobs are presented in this paper. The anonymous questionnaire survey was administered to municipal solid waste (MSW) collectors, as well as supervisors and safety officers (in longer form), in both public and private companies as part of a study to evaluate and reduce occupational risks to Florida Municipal Solid Waste (MSW) workers. Work practices, injuries, illnesses, and working environment reported by 251 responding collectors were analyzed. Results of the survey included reportedly high rates of lacerations, contusions, strain/sprains, and illness. In particular, 75% of the collectors surveyed reported having been injured in the past 12 months, consistent with findings of a previous analyses of Florida Worker’s Compensation data and facility accident logs, as well as the Danish MSW literature. Worker responses regarding reasons for injuries and illnesses were used to develop recommendations for reducing risks to MSW workers. Recommendations focuse on management and supervision of workers, communication among route workers, public education regarding risks to collectors from local vehicular traffic and improper disposal, and the design of safety equipment.

Key Words: Health and safety; injuries; municipal solid waste (msw); survey; risks

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Composting Spent Organic Sorbents With Residual Hydrocarbons And Reusing The Finished Compost As A Soil Amendment For Marsh Grass

K.S. Ro(1), B.B. Barrow(2), G. Breitenbeck(3), and D.D. Adrian(2)

(1)Dept. of Civil Engineering, City College of City University of New York
138th Street and Convent Avenue, New York, NY 10031 USA

(2)Dept. of Civil and Environmental Engineering, Louisiana State University
Baton Rouge, LA 70803 USA

(3)Department of Agronomy, Louisiana State University
Baton Rouge, LA 70803 USA


The overall objective of this study was to expose twelve natural sorbent materials to sweet Louisiana crude oil, then to compost the used sorbent materials after removal of part of the sorbed oil, and to apply the composted materials to marsh grass as a soil amendment. CO2 evolution history was recorded to measure the compostability of the used natural products, which had been treated with supplemental nitrogen sources. Plant growth tests were carried out in greenhouses using marsh grass (Spartina patens) growing in soils that had been enriched with the composted materials. The sorbents varied widely in the amount of sorbed oil they would hold and release after being pressed to 68.9 kPa. The amount of nitrogen in many sorbents yielded a C:N ratio that was larger than 30:1, the value considered optimal for composting, so that nitrogen fertilizers were applied to bring the C:N ratio to 30:1. Biological activity of spent sorbents increases with application of urea formaldehyde, but decreased with application of other nitrogen sources. The volume of spent sorbents reduced up to 73% of initial height after 184 days of pilot-scale composting. The stem growth rates of the marsh grass treated with various amounts of finished corncob and KsorbTM sorbent composts were not significantly different from that of the control plants for the most of testing period. The plants treated with finished Oil GatorTM compost showed enhanced stem growth rate compared to the control plants at a significance level of 0.05. The finished compost did not exert phytotoxicity toward the marsh grass.

Key Words: Spent sorbents, composting, soil amendment, oil spill cleanup residuals

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Issue 2, May 2002

Briquettes Of Olive Cake As A Potential Source Of Thermal Energy

Mohamad I. Al-Widyan, Adnan I. Khdair
Assistant Professor
Department of Agricultural Engg. & Technology

Ghassan Tashtoush
Assistant Professor
Department of Mechanical Engg.

College of Engineering, Jordan University of Science and Technology
P.O. Box 3030, Irbid 22110, JORDAN


Mediterranean countries produce annually large amounts of olive cake that impose disposal and environmental problems. This study involved an assessment of the potential of olive cake cylindrical briquettes as an energy source. Batches of the briquettes were burned in a lab-size metal, refractory-lined stove. The assessment was based on monitoring the combustion behavior of briquettes in the stove, measuring the various combustion temperatures, evaluating the stove performance, and sampling and analyzing exhaust emissions. It was found that despite their poor ignitability, the briquettes would burn efficiently and satisfactorily given adequate combustion air quantity and distribution. The stove efficiency burning the briquettes reached 80% with an average total burning time of 80 minutes per 520-gram batch. The flame temperature reached 350 °C with natural airflow and increased up to 500 °C as combustion air reached 196% theoretical. Carbon monoxide concentration in the exhaust gases decreased as airflow rate increased, which indicated better combustion with higher airflow rate for the ranges considered.

Key Words: Solid waste, Olive cake, Briquettes, Combustion, Exhaust gases, Stove

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Defining Options For Integrated Management Of Minicipal Solid Waste In Large Cities Of Low-Income Economies—The Case Of The Accre Metropolis In Ghana

N. Fobil
Graduate Research Assistant
Environmental Science Programme, Faculty of Science

D.  Carboo
Senior Lecturer
Department of Chemistry

C. Christian,
Department of Biochemistry

University of Ghana
P.O. Box 71, Legon, Accra, GHANA


Waste management and planning authorities need to know and understand the materials they will be handling or disposing in order to be able to set up effective sustainable waste management programmes. Also, in setting up a waste management programme for a region or city, it is critical to have reliable data on waste stream characteristics such as the nature, characteristics, types and quantities of waste components in the waste streams of that locality. This will allow them to choose with fair certainty the kind of management options to consider for the implementation of an integrated solid waste management programme. The objective of this study was to analyse household solid waste to determine the type, nature and quantities of materials in the waste as generated so to provide useful information on the potentially available management choices in the Accra metropolis. Results of the study show that, domestic solid waste in the metropolis can be routed via three distinctly different stream types; namely the High-Income Low-Density Population Waste Zone (HILDWZ), Middle-Income Medium-Density Waste Zone (MIMDWZ), and Low-Income High-Density population Waste Zone (LIHDWZ). These waste streams were also shown to consist of entirely different proportions of the waste components, but with an average percentage composition of 60% organic or putrescible materials, 8% paper & card, 8% plastic & rubber materials, 3% metal & cans, 2% glass, 11% residue or inert materials, and 2% miscellaneous or other waste.

Key Words: Pulverized waste, integrated waste management, waste stream, low-income, variability coefficient, Ghana and sustainable

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Leachate Generation And Transport From Solid Waste Disposal At A Former Quarry Site

M. El-Fadel, E. Bou-Zeid
American University of Beirut
Faculty of Engineering and Architecture
Bliss Street, P.O. Box 11-0236

W. Chahine
Lebanese University
Department of Civil Engineering
Roumieh, LEBANON


The present research work simulates leachate quantity generated at a 2000 tons/day landfill facility and assesses leachate migration away from the landfill in order to control associated environmental impacts, particularly on groundwater wells down gradient of the site. The site offers unique characteristics in that it is a former quarry converted to a landfill and is planned to have refuse depths in excess of one hundred meters, making it one of the deepest in the world. The modeling estimated leachate quantity and potential percolation into the subsurface using the Hydrologic Evaluation of Landfill Performance (HELP) model. A three-dimensional, multi-phase, variably saturated model (PORFLOW) was adopted to simulate subsurface flow and contaminant transport in a fractured porous medium. While the models showed that significant potential adverse impacts were confined to the immediate vicinity of the landfill, simulation results confirmed the importance of point-of-compliance specifications in landfill performance criteria.

Key Words: Solid waste landfilling, leachate generation, HELP, subsurface transport, PORFLOW

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Reduction Of Volatile Organic Compounds And Stabilization Of Industrial Biosoilds Through Composting

K.C. Das, M.Y. Minkara, J.R. Kastner, 
Department of Biological & Agricultural Engineering

S.M. Hassan
Department of Crop & Soil Sciences

The University of Georgia
Athens, GA 30602-4435


Industrial biosolids containing high levels of volatile organic compounds (VOCs) are sometimes regulated as hazardous wastes restricting their direct beneficial reuse. Therefore, they are disposed off in landfills or through incineration, which tend to be expensive and environmentally unsustainable options. Composting was examined as a potential method for the reduction of VOCs in these industrial biosolids. The goal of this research project was to monitor the presence of VOCs in biosolids during the composting process. Volatilization due to high temperature and air stripping along with microbial biodegradation were responsible for eliminating more than 85% of the major VOCs within a period of 14 d and more than 93% after 35 d of composting. Industrial biosolids compost product was comparable in compost stability, nutrients, and other agronomic properties to municipal biosolids compost produced under the same conditions. Therefore, composting could be used to stabilize industrial biosolids containing VOCs and convert them into a beneficial product.

Key Words: Industrial biosolids, Disposal, VOCs, Biodegradation, Volatilization, Air stripping

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Solid Waste Management In Kuwait

Jasem M. Alhumoud, Ph.D.
Department of Civil Engineering
Kuwait University
P.O. Box 5969
Safat 13060


The main objective of this paper is the investigation of current solid waste management practices in Kuwait. Recent literature on solid waste management in Kuwait has been reviewed and data analyzed on the total amount of solid waste generated in Kuwait. The results show a rapid increase in the total amount of municipal solid wastes and significant changes in their composition. These are related to the increased population in Kuwait and the lavish spending. The total solid waste generation has reached 1.4 kg per capita per day. Vehicles for waste collection include rear-loading compactors, non-compacting trucks, container hauling trucks, open tippers, and side loaders. Refuse analysis indicated a high percentage of food and paper/cardboard products. The total amount of industrial solid waste in Kuwait was about 1.24 tonnes in 1997. Also, the total amount of pharmaceutical wastes was about 25.2 tonnes in the same year. Factors affecting the important management issues in the operation of Kuwait’s solid waste management system are discussed. Key design data and other useful information selected from a variety of reliable sources are presented. The adoption of modern waste management practices should be emphasized in order to achieve greater efficiency.

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Solid Waste Workers:  Occupational Exposures And Health

Lora E. Fleming , MD Ph.D. MPH MSc, Melissa Danits, MPH
Department of Epidemiology and Public Health
University of Miami School of Medicine
1801 N.W. 9th Avenue, Highland Park Building, Suite 200
Miami, FL   USA 33136

Judy A. Bean, Ph.D.
Biostatistics Program
Children’s Hospital of Cincinnati
Cincinnati, OH

James Englehardt, Ph.D., Jeff An, MSc,
Nicolette John, MS, Jeffrey Rogers, BS
Department of Civil Engineering, College of Engineering
University of Miami
Coral Gables, FL


Although solid waste generation is increasing worldwide, the occupational exposures and health risks of solid waste workers are not well understood. This review focuses on the peer-reviewed published medical, epidemiologic, and toxicologic literature, and available governmental reports. Studies from developed and less developed nations, as well as studies on other relevant workforces (such as hazardous waste workers), were also reviewed. Solid waste workers are exposed to significant levels of physical, chemical and biological toxins. Injury, as well as acute and chronic musculoskeletal, dermal, and respiratory health effects, are well documented among these workers. Engineering controls, exposure monitoring, education, personal protection, and other interventions are under-utilized in protecting solid waste workers from exposure and health effects. Specific recommendations are suggested for reducing exposures and occupational health effects of solid waste workers. Additional research is needed to further characterize the exposures and health effects of these workers.

Key Words: Literature Review, Solid Waste, Occupational Disease, Occupational Injury, Exposures, Solid Waste Workers

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Issue 1, February 2002

Decisional Model For Integrated Management Of Muncipal Solid Waste—A Case Study

G. d’Antonio, M. Fabbricino, F. Pirozzi
Department of Hydraulic and Environmental Engineering ‘Girolamo Ippolito’
University of Naples ‘Federico II’
via Claudio 21
80125 – Naples, ITALY


In order to develop an integrated system for solid waste management, the Campania Regional Administration (Italy) has divided the region into two territorial areas. For each of these a decisional model is applied so as to define the composition and the amount of solid waste flows to be collected and diverted to the treatment plants. Six different scenarios are considered, corresponding to the successive phases of Regional Programme implementation. An optimisation algorithm for the solution of the decisional model is used to spread the waste components among the envisaged plants with or without source-separated collection, while imposing four objectives for minimum material recovery. The obtained results are discussed and compared for the assumed cases in order to arrive at the best technical and economic solution of waste management, i.e. compatible with choices made by the Regional Programme, for the different phases of the municipal solid waste management plan.

Key Words: Solid waste, integrated system, decisional model, source separated collection

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Explosion Hazards And Explosion Protection During The Construction Of Landfill-Gas-Wells

Burkhard Forell
Technical University of Braunschweig
Fliederweg 20, D-33100 Paderborn

Prof. Dr. rer. nat. em. Hans Hölemann
Föhrenstrabe 31, D-44289 Dortmund


During the construction of landfill-gas wells an atmosphere made up of air and LFG develops inside the borehole in which the content of air decreases with depth. Because LFG has a high content of fuel gases, the atmosphere inside the borehole is partly ignitable. To determine its explosion limits a tenary diagram of air, methane and inert gases is suitable, with the inert gases carbon dioxide, additional nitrogen and water vapor.
As ignition sources mechanically caused sparks from the movements of the drilling tool have to be taken into account. Sparks resulting from steel to steel interactions as a rule have insufficient ignition energy. Therefore probably only certain material combinations like iron grate and light metals provide incendive sparks.
Filling in the aggregate into the borehole has reportedly lead to ignitions.
The intensity of an explosion inside the borehole depends on different influences:
· an atmosphere of LFG and air sets free relatively small amounts of energy, but
· explosions in pipelines are accompanied by turbulence produced by the axial flows which speed up the explosion.
Here the volume and the dispersion of the ignitable atmosphere as well as the place of ignition are of great importance.
Hazards for the drilling personnel and especially the drilling assistant from hurled-out refuse and hot fire gases are to be expected – not, however, that the drilling tool will be pressed out of the borehole by an explosion.
A primary measure of explosion protection against the development of ignitable atmosphere above the borehole is the use of fans diluting the outflowing LFG.
Explosion protection inside the borehole is rarely employed. An effective measure would be to render the borehole inert with carbon dioxide or nitrogen. However this measure requires considerable expenditure.

Key Words: Landfill, Landfill-Gas, LFG, Explosion, Explosion Protection, Well, Drilling, Ignition Source, Inerting

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Industrial Solid Waste Management And Joint Production

Jan Stenis
Department of Technology
University of Kalmar
SE-391 82, Kalmar, Sweden


The study illustrates how joint production theory can be applied in estimating the profitability of fractionating industrial solid wastes, a given product and the wastes produced in connection with its manufacture being regarded as a production-planning unit. Two case studies showing how the approach described can be applied both to bulk manufacturing and to the manufacture of technically complicated products are presented. The realism of this approach and the contribution it can make to optimizing the separation of industrial solid waste fractions in manufacturing processes of different types, together with associated financial considerations, are discussed.

Key Words: Industrial solid waste management, joint production

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Lead-Contaminated Soil Disposal In Non-Hazardous Waste Landfills—Groundwater
Effects And Policy Implications

Edward L. Ferguson
Howrey Arnold & White Simon
Washington, DC  USA

Mark McBride
Capital Analysis Group
Washington, DC  USA


Lead-contaminated soil that fails the Toxicity Characteristic Leaching Procedure (“TCLP”) test must be managed as hazardous waste under the Resource Conservation and Recovery Act (“RCRA”) and disposed in Subtitle C landfills. We examine the actual risk to groundwater from the management and disposal of lead-contaminated soil in non-hazardous waste landfills. Lead concentrations in leachate-affected groundwater were modeled using EPA’s Monte Carlo Composite Model for Leachate Migration with Transformation Products (“CMTP”). Simulated leachate concentrations were based on Synthetic Precipitation Leaching Procedure (“SPLP”) and TCLP tests of soil from lead-contaminated Superfund sites. Receptor well lead concentrations were less than the drinking water standard (0.015 mg/L) in 98.5% of the SPLP scenarios, and 96% of the TCLP scenarios. These were more protective than the level EPA used to justify a proposed conditional exclusion from the RCRA hazardous waste program for architectural debris containing lead-bearing paint, allowing disposal of such debris in non-hazardous waste landfills. Since the risks to groundwater from lead-contaminated soil disposal are less than those from architectural debris, EPA should allow lead-contaminated soil that fails the TCLP to be disposed in non-hazardous waste landfills. This would reduce the costs of its management and encourage greater remediation of lead soil hazards.

Key Words: Lead, soil contamination, soil disposal, groundwater, leachate, leaching tests

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Measurement Of Dioxins In Waste Incinerator Fly Ash Residues And Their Destruction   By Sintering

D. B. Ward, P. H. Lee, V. Nasserzadeh, J. Swithenbank
Sheffield University Waste Incineration Centre (SUWIC)

C. W. McLeod, P. Clarkson
Centre for Analytical Sciences (CAS), Sheffield University

John Upton
Varian Analytical Instruments

John Laming, Mike Holmes
Dyson Hotwork Engineering


The waste incineration industry is faced with ever more demanding environmental legislation regarding its wastes. One example is the new European dioxin limit of 0. 1 ng/Nm3 ITEQ (International Toxic Equivalent Quantity) in atmospheric emissions. This has added to demands for further investigation into the formation, prevention and removal of dioxins in all aspects of waste incineration. Modern incinerator gas cleaning plants have proved extremely successful in reducing polluting emissions to atmosphere; however, the toxic fly ash residues generated by such systems pose a significant disposal problem. Waste incineration will only gain full public acceptance if the innocuous quality of all outputs can be guaranteed. At present the ash produced by the waste incineration industry is landfilled but at considerable cost due to toxic heavy metals and organics content. Detoxified ash would prove cheaper to landfill and may even have potential uses in the construction industry.
In the past few years, the Sheffield University Waste Incineration Centre (SUWIC) has been carrying out extensive research in order to develop a cheap, reliable and effective technology for the detoxification of incinerator ash. A novel, energy efficient, ash sintering technology has been developed and has shown considerable success in immobilising leachable heavy metal fractions. A series of tests are currently being carried out in order to examine the extent to which dioxins are destroyed by this novel sintering process. This paper presents the results obtained from this study.

Key Words:  Fly ash, Sintering, Dioxins/Furans, Ion trap Mass Spectrometry, Waste Incineration, Heat Regeneration

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Odour Impact Evaluation Of Municipal Waste Composting Unit

Anjali Srivastava, Rakesh Kumar
National Environmental Engineering Research Institute (NEERI)
89-B, Dr. Annie Besant Road
Worli, Mumbai – 400 018, INDIA

National Environmental Engineering Research Institute (NEERI)
Nehru Marg, Nagpur – 440 020, INDIA


Municipal solid waste composting is becoming an acceptable technical solution for many city municipalities in India. Though composting as an alternative of solid waste management is being accepted readily, odour emission from compost piles and its effect on population has been a major concern.
An attempt has been made to study the odour impact due to compost plant through modeling, using two approaches viz. estimating peak to mean ratio for comparison with odour threshold values and estimation of plume width along with odour threshold concentration.
The study indicates that predictions of odour impact by two approaches give fairly good agreement. However, plume width approach does not provide information regarding duration of occurrence of various odour levels. In the other approach of peak to mean ratio estimation, estimation of intensity of fluctuation accounts for variation in concentrations away from the mean value.
Odour response appears to relate to fluctuations of concentrations around the mean values. The concept of peak to mean ratio provides better objectivity in identifying odour impact areas.

Key Words: Odour Dispersion, Composting, Municipal Solid Waste

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