Issue 4, November 2006
A NATIONAL APPROACH TO CLINICAL WASTE MANAGEMENT
Enhealth Sdn. Bhd.
16-1, Jalan 3/27F, Wangsa Maju, 53300 Kuala Lumpur, MALAYSIA
Ministry of Health, Malaysia
Block E6, Government Complex Parcel E, Precinct 1
Federal Administrative Centre, 62604, PUTRAJAYA, Malaysia
Ministry of Health, Malaysia
Block E6, Government Complex Parcel E, Precinct 1
Federal Administrative Centre, 62604, PUTRAJAYA, Malaysia
Before 1990 clinical waste in Malaysia was handled in a similar manner as any other solid waste within the hospital. This practice together with the lack of adequate disposal sites resulted in various unfortunate incidents, such as abuse of needles by drug addicts and scavenging of body parts by stray dogs. Such incidents and increasing concerns about HIV spurred the Malaysian Ministry of Health and Department of Environment to have clinical waste regulated under the Environmental Quality (Scheduled Wastes) Regulations 1989. The Ministry of Health also developed Guidelines on the Management of Clinical Waste and Other Related Wastes.
However, lack of resources and infrastructure were identified as impediments for full compliance with Malaysia’s Environmental Quality (Scheduled Wastes) Regulations and international standards on good management practices for clinical waste. Hence a decision was taken in 1993 to privatise this service for the Ministry’s 127 hospitals and institutions throughout the country. This unprecedented move, while providing a solution to the problem of managing clinical waste, presented a whole new set of challenges. These include among others project viability and sustainability as well as maintaining quality of service in the face of commercial pressures.
Some of the measures taken included awarding the contract to three Contractors, thus ensuring that there would be no monopoly and services could be taken over by either of the two Contractors in the event that one fails to deliver services. The approach taken in privatising the services took into account private sector’s need for profitability, thus encouraging private sector participation and at the same time ensuring project viability and sustainability. However to ensure a balance between profitability and public good service, the Concession Agreement (CA) with the three Contractors incorporated technical requirements, performance indicators, procedures and various other requirements to which the Contractors had to comply. Mechanisms such as a Deduction Formula and the right of the Government to engage third parties to provide services in case of poor performance by the Contractors were also incorporated into the CA.
With privatisation, the country has one of the best managed clinical waste management services in the region with dedicated vehicles and treatment facilities in place. The services have also been extended to all private hospitals and other government hospitals in Malaysia. With the experience gained in providing services in Malaysia, the Contractors are also selling their services and expertise abroad.
Keywords: Clinical waste; privatize, national approach; challenges; project viability and sustainability; quality of service
THE IMPACT OF LOCAL MANDATORY RECYCLING POLICY ON CITIZEN RECYCLING BEHAVIOR — A TEST OF AN INTEGRATED MODEL
Institute of Public Affairs Management, National Sun Yat-sen University
70 Lai-Hwai Rd., Kaohsiung 80424, Taiwan
REPUBLIC OF CHINA
The aim of this study was to determine how the mandatory household recycling policy that was changed from the previous voluntary one, affects the household recycling behavior of citizens, as well as possible solutions for waste management. An integrated household waste management model, based on the Theory of Planned Behavior, was employed for exploring determinants of recycling behavior. The findings indicate that the mandatory program has met with some success. The policy implications are presented as well.
Keywords: Theory of planned behavior, recycling, recycling behavior, mandatory recycling policy, waste management, structural equation modeling
STUDIES UTILIZING HIGH TEMPERATURE FEEDING RECYCLE RESOURCES ULTRA-LIGHT AGGREGATE
Su-Chen Huang, Chu-Fang Wang
Department of Nuclear Science, National Tsing Hua University
Hsinchu 300, Taiwan, R.O.C.
Ming-Yu Lee, Jeng-Ching Lee, Jyh-Dong Lin
Department of Civil Engineering, National Central University
300 Jhongda Rd., Jhongli 320, Taiwan R.O.C.
Fang-Chih Chang, Shang-Lien Lo
Research Center for Environmental Pollution Prevention and Control Technology
Graduate Institute of Environmental Engineering, National Taiwan University
71 Chou-Shan Road, Taipei 106, Taiwan, R. O. C.
Artificial ultra-lightweight aggregate (ULWA) manufactured from recycled resources was investigated. Residues from mining, fly ash from incinerator and heavy metal sludge from electronic waste were mixed into raw aggregate pellets and fed into a plow-type tunnel kiln to be sintered and finally cooled rapidly. Various feeding and sintering temperatures were employed to examine their impact on the extent of vitrification on the aggregate surface. Microstructural analysis and toxicity characteristic leaching procedure (TCLP) were also performed. Our results show that the optimum condition of ULWA fabrication is sintering at 1150�C for 15 min with raw aggregate pellets fed at 750�C. The rapidly vitrified surface envelops the gas produced with the increase in internal temperature and cooling by spraying water to prevent the aggregates from binding together, thus forming ULWA with specific gravity below 0.5. ULWA produced by sintering shows good vitrified surface, water absorption below 10% and high cylindrical compressive strength. In addition, only trace amounts of heavy metals were detected, making the ULWA non-hazardous for construction use. With sintering time reduced to within 20 min, ULWA can be manufactured in larger quantity and shorter time, promising an alternative for profitable resource recycling and efficient waste management.
Keywords: Light weight aggregate, Plow-type tunnel kiln, Shale, Rotary kiln
RECOVERY AND RECYCLING OF POLYMERS FROM SHREDDER RESIDUE
Bassam J. Jody, Joseph A. Pomykala, Jr., Jeffrey S. Spangenberger, Edward J. Daniels
Argonne National Laboratory
Energy Systems Division
9700 South Cass Ave
Argonne, Illinois 60439
Metals recovery from end-of-life automobiles, home appliances and other metals containing scrap involves shredding these items and then recovering the metals from the shredded material. The remaining non-metallic fraction, commonly called shredder residue is presently landfilled. Over four and a half million metric tonnes of shredder residue is generated in the United States annually and essentially all of it is landfilled. About 15 million tonnes are generated worldwide. Shredder residue contains, among other materials, polymers that could be recovered and recycled. Argonne National Laboratory is developing technology for producing revenue streams, such as plastics, from shredder residue. This paper describes a process developed by Argonne National Laboratory for the separation and recovery of plastics from shredder residue. The process consists of two parts. First, the plastics are mechanically separated from the shredder residue as a mixed polymer concentrate and then the individual plastics are separated from the polymer concentrate via a froth flotation process. The process has been demonstrated in a mechanical separation pilot plant that has a design capacity of 1.8 tonnes/hour followed by a froth flotation pilot plant that has a capacity of 500 kg/hour. Preliminary process economic analyses indicate that the process is potentially economical.
Keywords: Shredder residue, recycling, plastics, separation, polymers, metals
ENHANCING THE WORKABILITY OF RECYCLED RUBBER-ASPHALT APPLICATIONS WITH THE ADDITION OF NEW POLYMERS
Magdy Abdelrahman, Ph.D.
Department of Civil Engineering
North Dakota State University
201F CIE Building
Fargo, ND 58103
The use of recycled materials in asphalt applications is growing rapidly. Adding crumb rubber (CRM) improves the performance of different asphalt applications. Modifications to asphalt properties using CRM are slightly different as compared to those of virgin polymers. Certain asphalt properties are modified more effectively using virgin polymers. Enhancing the performance of asphalt-rubber (CRM) applications through the addition of polymer modifiers has been successful. Modifiers can also improve the handling and workability of CRM binders and mixes. This paper documents some of the key efforts using CRM modification with enhanced performance through the addition of polymer modifiers. The paper provides some clear insights into the mechanisms by which the interaction, with and without the existence of polymer modifiers, takes place. The effects of the interaction process variables, time and temperature and pre-processing, are explained. The results of this research are based on monitoring the changes in the rheological parameters of the developed binder. The extent of using virgin polymers, in addition to CRM, to achieve specific asphalt modification is discussed.
Keywords: CRM, Asphalt, Crumb Rubber Modifier, Asphalt-Rubber Binder, CRM-Polymer-Asphalt, CRM Binder Separation
A RADICAL NEW, ENVIRONMENTALLY ACCEPTABLE APPROACH TO HAZARDOUS WASTE MANAGEMENT IN THE UK —A CASE STUDY OF PLASMA ARC TECHNOLOGY
D.E. Deegan, C.D. Chapman, S.A. Ismail, M.L.H. Wise and H. Ly
5 Lechlade Road, Faringdon, Oxfordshire, England, SN7 8AL
School of Applied Science, University of Northampton
Northampton, England NN2 7AL
Driven by European legislation the UK has commenced a new phase in waste management where it seeks to introduce new and cost effective technologies to manage a range of wastes – including hazardous. Key to all these developments is the demonstration to the public that the new technologies are `environmentally friendly` and do not in themselves create problems through excess production of say hazardous residues. The use of plasma arc technologies, especially in the treatment of hazardous wastes, is set to expand in the UK. The technology is intermediate within the waste management hierarchy and is characterised as an Advanced Conversion Technique (ACT) with Best Available Technique (BAT) attributes. Adoption is driven by the increasing stringency of environmental regulations, the requirement for efficient resource utilisation, the responsibility of original equipment manufacturers (OEMs) for product life cycle impact and the reducing capacity of traditional disposal mechanisms. Within this industrial climate, plasma technology is set to become an important component of sustainable waste management solutions. Tetronics’ technology is mature and has been successfully employed in a range of commercial-scale environmental applications. This paper reviews recent developments in plasma arc technology for the treatment of Asbestos Containing Material as well as general aspects of other future prospects.
Issue 3, August 2006
CHARACTERISTICS OF CHAT-ASPHALT FOR ROAD BASE APPLICATION
Nazimuddin M. Wasiuddin, Musharraf M. Zaman, Robert W. Nairn, Nishad Kolothody
More than 35 million cubic meters of mine chat, a waste material from abandoned lead and zinc mining operations, are presently stockpiled at the Tar Creek Superfund Site. Currently, the Oklahoma Department of Transportation (ODOT) uses a rather small percentage (about 20%) of washed (not raw) chat in hot mix asphalt (HMA). No systematic bench-scale tests, incorporating different percentages of chat, have been performed previously for characterization of raw chat in HMA in an environmentally responsible manner. In order to maximize the use of raw chat in chat-asphalt, three different base mixes having three different percentages of raw chat were prepared according to the Superpave mix design methodology. It is observed that raw chat is an excellent source of aggregate in HMA for road base. As much as 50% raw chat can be used in an S3-type Superpave base mix. Chat-asphalt mixes also did well in performance tests, namely moisture susceptibility, APA rut, and permeability. A suite of environmental tests was performed to examine the leaching potential of heavy metals (lead, zinc, and cadmium) in chat-asphalt due to dry and wet rut tests, and simulated milling. Test results indicate that chat-asphalt can be used safely as a roadway base.
Keywords: Tar Creek Superfund Site, Chat, Road Base, Superpave Mix Design, Leaching Potential, Heavy Metals
RECOVERY OF PROTEINACEOUS MATERIALS FROM TANNED SOLID WASTES — YIELDS AND CHARACTERIZATION OF ISOLATED PRODUCTS
Facult� des Sciences d’El Jadida. D�partement de Chimie.
Universit� Choua�b Doukkali. B.P.20. El Jadida. Maroc.
Facult� des Sciences et Techniques – Mohammedia. Universit� Hassan II.
B.P.146. Avenue Hassan II, C.P.20650. Mohammedia. Maroc.
M.R. Abargues, M. de la Guardia
Departamento de Quimica Analitica – Edificio de Investigacion
Universidad de Valencia – C/Dr.Moliner, 50 – 46100 Burjassot.
Tanned solid wastes have a highly organized structure in the form of fibers (Φ : 100nm) which are very tight to each other. These wastes are formed mainly by proteins (75-79%). The amount of chromium oxide is about 4.4%. The alkaline digestion of chromium tanned wastes to recover proteins products was studied using three alkaline agents: calcium hydroxide, sodium hydroxide and sodium carbonate. The chrome cake was also recovered as co-product. Alkaline agent concentration and reaction time were chosen as parameters to improve the process. The yields of the proteins products and material balances were calculated by weighing the isolated products throughout the process and by determination of their physico-chemical characteristics. Proteinaceous materials from the three digestion procedures were analysed using ICP-OES method for multielement determination and Ion Exchange Chromatography for inorganic anions analysis. The obtained results were compared.
Keywords: Tanned solid wastes, digestion, proteins, chromium, yields, characterization
COMPARISON OF APPROACHES TO CHARACTERIZE THE UNIT WEIGHT OF MSW IN LANDFILLS
J.W.F. Morris, C.A. Lazarte, C.H. Pendleton, and R.D. Espinoza
Columbia, Maryland, USA
Atlanta, Georgia, USA
University of Texas
Austin, Texas, USA
Delaware Solid Waste Authority
Dover, Delaware, USA
ABSTRACT An evaluation of the unit weight of in-place waste at municipal solid waste landfill based on multiple field techniques is presented. The composition and moisture content of the waste, as well as the presence of standing liquid were also investigated. The field investigations consisted of spectral analysis of surface waves surveys, large-diameter bucket auger test borings, collection of bulk waste samples for waste classification and laboratory analysis, small-diameter rotary auger test borings, cone penetrometer test soundings with pore pressure dissipation measurements, and groundwater level measurement in gas wells. Data from existing in situ instrumentation and historical site records and surveys were also used to estimate waste unit weight. Overall, the large diameter borings were considered to provide the best data for evaluating waste unit weight. Values for waste unit weight and trends of unit weight with depth published in literature were used to complement and critically evaluate findings from this investigation. Based on this, final recommendations for the variation of waste unit weight with depth at the site after final construction, when the total depth of waste in place will likely exceed 75 m, were developed.
Keywords: in-situ, unit weight, MSW, landfill, waste characterization, SASW
A COMPARATIVE STUDY OF THE ATTITUDE OF HOUSEHOLDS TOWARD RECYCLING OF SOLID WASTES IN MALAYSIA AND VIETNAM — CASE STUDIES OF PENANG, MALAYSIA AND HO CHI MINH, VIETNAM
Abdelnaser Omran, Abdullah Mahmood
School of Housing, Building and Planning
11800, Minden, MALAYSIA
Hamidi Abdul Aziz
School of Civil Engineering
14300, Nibong Tebal, Seberang Selatan
Universiti Sains, MALAYSIA
Tran Tuyet Mai
School of Environmental Engineering & Management
45 Ngugen Khac Nhu, Phuong Co Giang, Quan 1,
TPHCM Van Lang University, VIETNAM
Recycling of solid wastes is now recognized as the “most environmentally sound” strategy for dealing with MSW following only the preventive strategy of source reduction and reuse. The main objective of the paper was, to gain information about attitude of households toward recycling of solid wastes in Malaysia and Vietnam. The research involves administration of 600 survey questionnaires to households in Penang, and in Ho Chi Minh City, of which 409 for Penang and 373 responses of Ho Chi Minh City respectively were returned and analyzed. The result indicated that, if recycling is to be adequately developed as an effective alternative to landfill disposal, public participation must be increased. The campaign focused too much emphasis on getting households to bring their recyclables to recycling centers. The problem worsens because the number of collection centers is inadequate and cannot be easily located. The poor response is largely due to the lack of facilities provided. Many residents are turned down when they are unable to locate the recycling centres and if they are able to locate one, it seems too troublesome to be needed. A lesson from this study is that households attitude can be improved if adequate recycling facilities are provided. These facilities must be strategically located and within easy reach so that the households are not unnecessarily inconvenienced or discouraged to bring their recyclables. The Malaysia and Vietnam solid wastes recycling programme were found to be conflicting, lacking in direction and funding. Clear goals and more awareness need to be established.
Keywords: Comparative Study, Recycling Campaign, Solid Waste Recycling, Households Attitude, Vietnam, Malaysia
ARTIFICIAL NEURAL NETWORKS FOR ASSESSING WASTE GENERATION FACTORS AND FORECASTING WASTE GENERATION: A CASE STUDY OF CHILE
Eduardo Ord��ez-Ponce, M.E. (Nat Res)
Sandhya Samarasinghe, Ph.D.
Centre for Advanced Computational Solutions (C-FACS)
Lynn Torgerson, B.E.
Natural Resources Engineering Group, Lincoln University
P.O. Box 84, Canterbury, NEW ZEALAND
One of the bottlenecks in implementing waste management policies in Chile is the lack of information on factors correlating with waste generation. Recognising these factors is essential for implementing policies to reduce waste generation.
From over 40 global variables indicating demographic, socio-economic and climatic conditions, Population, Percentage of Urban Population, Years of Education, Number of Libraries, and Number of Indigents were identified as the most important factors correlating with waste generation in Chile, all relating positively. Using these variables, communes were clustered into groups from which representative communes were selected for further data collection for forecasting waste generation at a communal level. Artificial Neural Networks were used for identifying factors, clustering communes and forecasting waste generation.
The model is designed to represent most of the communes of a country. In this study, the best scenario represents 67.3% of the communes, based on the representativeness of each selected representative. However, due to lack of information, this rate decreased to 48.8%. Forecasted rates show that by 2010, representative communes will generate 100, 240 and 2,900 tonnes/month, with yearly variation rates of less than 1%. These predictions will be used to obtain estimates for each represented group and a significant portion of Chile.
Keywords: Artificial neural networks; waste generation; clustering; forecasting; Chile
UTILISATION OF WASTE PLASTIC BAGS IN BITUMINOUS MIX FOR IMPROVED PERFORMANCE OF ROADS
Associate Professor, Department of Civil Engineering
NED University of Engineering and Technology, Karachi-75270, PAKISTAN
Associate Professor, Department of Civil Engineering
Sir Syed University of Engineering and Technology, Karachi, 75300, PAKISTAN
The quantity and type of waste being generated is growing at enormous rate. The plastic wastes produced particularly in form of bags being non-degradable and with limited recycling options poses disposal problem. The probable solution as mentioned lies in effective recycling of the waste which in fact is restricted by economic and operational constraints hence demanding a sustainable solution for safe and ultimate disposal of waste plastic bags. An academic research aimed at probable use of waste plastic bags in pavement structure so as to come up with an ultimate safe disposal together with improvement in the performance of pavement through better mix design was undertaken. An aggregate material from waste plastic bags referred to as Recycled Plastic Waste Aggregate (RPWA) is developed which would partially replace the conventional material to improve desired mechanical characteristics for a particular road mix. Preliminary investigations have indicated that use of RPWA (1.2 – 3mm in size) in the surface and base mix design, when utilised up to 2.5% by weight substitution has shown improved stability and flow (Marshall test) having unit weight and bulk specific gravity falling within the acceptable limits for light and heavy traffic loads. It is envisaged that use of RPWA in the conventional asphalt hot mix design is likely to improve the pavement performance with a sustainable solution for the disposal of plastic waste.
Keywords: Waste Plastic Bags, Recycled Plastic Waste Aggregate, Marshall Flow and Stability, Sustainable Solution, Plastic Waste, Non-conventional Aggregate, Road Mix Design
Issue 2, May 2006
SOLID WASTE MANAGEMENT IN KATMANDU, CAPITAL CITY OF NEPAL
R. Alam, M.A.I. Chowdhury, G.M.J. Hasan, B. Karanjit, and L.R. Shrestha
Shahjalal University of Science and Technology
Among the multitude of environmental problem existing in the urbanizing cities of developing countries, solid waste has become one of the most prominent in the recent years, not only because of the increase in the amount, but chiefly because of the lack of an efficient system for its management. And Katmandu city is not an exceptional. This paper discusses Katmandu’s existing municipal solid waste management, its analyses, municipal solid waste production trends, and other related topics like conservancy wings, organizational and financial aspect to address the actual existing practice. Prediction of solid waste generation was done for an efficient waste management program and infrastructures that would be needed for the purpose.
Keywords: Composting, disposal, healthcare waste, Katmandu, solid waste, transfer station
IMPLEMENTATION OF ECOLOGICAL SOLID WASTE MANAGEMENT ACT: CHALLENGES AND INNOVATIONS
In response to the passage of Republic Act 9003 otherwise known as “Ecological Solid Waste Management Act of 2000,” the Industrial Technology Development Institute (ITDI) under the Department of Science and Technology has formulated a scheme for managing solid wastes generated from the various research divisions of the Institute.
The Institute has formed Solid Waste Management Group, established their own Material Recovery Facility (MRF) and beefed up their recycling efforts for laminates, styropor, PET, and PE bags. The Institute’s experience in managing their own solid waste has become a model for encouraging other research institutions and local government units to comply with the recently passed law on solid waste management.
Keywords: Solid waste; material recovery facility; ecological solid waste management; recycling; laminates; plastics
DETERMINANTS OF HOUSEHOLD RECYCLING AND WASTE MINIMISATION BEHAVIOUR: THE CASE OF MOULTON, NORTHAMPTONSHIRE, UK
Steve Smith and Thomas Coskeran
Liverpool John Moores University, School of Accounting, Finance and Economics
John Foster Building, 98 Mount Pleasant
Liverpool, L3 5UZ, UK
The University of Northampton, The SITA Centre
Boughton Green Road
Northampton, NN2 7AL, UK
The current climate, both political and ecological, is requiring local authorities in the UK and elsewhere to reduce waste disposal within their areas. An increasingly prominent strand of policy in this respect is to promote recycling and waste minimising behaviour by households, which can have a major impact on waste disposal. Various analytical approaches have attempted to establish the key determinants of household behaviour and thus of possible policy levers. Based on cognitive psychology, the Theory of Planned Behaviour is one such approach that provides a framework for studying links between attitudes and behaviour.
In this study, a questionnaire survey based on that theory, but also offering insights into alternative explanations of behaviour, examined attitudes towards recycling and waste minimisation in the village of Moulton, Northamptonshire, UK. Factor analysis and multiple regression analysis of responses to the survey suggest that the theory can explain some aspects of these behaviours in Moulton.
Economic theories of household behaviour suggest costs, benefits and incentives in choice will also be important drivers, a view given support by the results obtained. Overall, the study implies changes in the design of campaigns to encourage recycling and waste minimisation that will need to be considered in the future.
Keywords: Theory of Planned Behaviour, waste minimisation, recycling, household choice, incentives, policy
SORPTION AND LEACHING OF HEAVY METALS IN THE ANAEROBIC TREATMENT PROCESS OF ORGANIC SOLID WASTE
Valderi Duarte Leite
Department of Chemistry, Center for Sciences and Technology
State University of Paraiba (UEPB), 58100-000 Campina Grande, PB, BRAZIL
Department of Hydraulics and Sanitation, School of Engineering at Sao Carlos
University of Sao Paulo (USP), Sao Carlos, SP, BRAZIL
Department of Chemical Engineering, Center for Sciences and Technology
Federal University of Campina Grande (UFCG), P.O Box 10108
CEP 58109-970 Campina Grande, PB, BRAZIL
The behavior of eight different heavy metals present in municipal solid waste “in natura” when submitted to anaerobic biostabilization process has been studied in this work. The results of this work reveal what would happen in a reception system of municipal solid waste when its composition contains a significant gravimetric percentile of metallic material. When fermentable organic matter present in municipal solid waste is submitted to biostabilization process, the metallic material undergoes redox process and it releases the metallic species to the medium, a part of that is retained in the waste mass and the other part is carried by the leached, thus being related to environmental problems. The results produced by this research showed that approximately 45 wt% of the influent heavy metals was retained in the mass of the biostabilized municipal solid waste. Thus, demonstrating that, regarding municipal solid waste treatment, the sorption study results can bring a significant contribution to the area of the treatment of solid waste such as the municipal solid waste.
Keywords: Sorption, leachate, leaching, anaerobic process, heavy metals, solid waste
POPULATION, RESIDENTIAL SOLID WASTE GENERATION AND CONTAINERS NEEDED IN MOSUL CITY
Obey M. AL-Wattar
Faculty of Administration & Economics
Dumps of residential solid waste (RSW) has been visible in the districts of Mosul City long time before the 2003 war. Moreover, in some districts, residents and others take their solid waste to the banks of River Tigris, causing further pollution to this relatively large and fast flowing river. The Directorate of Mosul Municipality (DMM) is doing what it can to provide a sort of minimum collection, transfer, and disposal services to the city. When the funding for these services dries up, dumps of RSW (and other solid waste) become more visible. Having no reliable and detailed data on RSW generation for Mosul City and its districts to bite on, the DMM had to rely on the unrealistic RSW generation rate of one kilogram per capita a day (kg/capita/day) for planning and budgeting purposes. This mini-project attempts at bringing the DMM closer to such data, using a sample survey. The estimated RSW generation rate at source for Mosul City, using the survey data, has been around 0.3kg/capita/day. With an estimated city population of 1.2 million or so, RSW generation would be some 400 tons a day. The study includes, among other things, RSW generation for each municipal section of Mosul City, and containers need for twelve of its districts. The author concludes the study with some recommendations.
Keywords: Containers, Dumps, Generation, Management, Municipal Waste, Mosul
APPLICATIONS OF STATIC SCREENS FOR RECOVERY OF PLACER VALUES FROM SPIRAL TAILING
Ashok Kumar Sahoo, Ranjita Swain and R. Bhima Rao
Regional Research Laboratory, (CSIR)
Bhubaneswar, 751 013, India
Use of micro screen in effective separation for specific cut size and recovery of valuables from spiral tailings of beach sand is discussed. With increasing deck angle of micro screen from 50� to 74�, the specific cut size of the spiral tailings decreases from 100 to 45 micron. The overflow of micro screen containing 86% of material may be rejected, incurring overall loss of only 0.37% of heavy minerals. The screen underflow that gets enriched in heavies (19.3%) may be recirculated to the plant, so that higher recovery of such heavy minerals can be achieved.
Keywords: Micro Screen, Beach Sand, Hydro Cyclone, Spiral Concentrator, Under Flow, Over Flow, Tromp Curve, Spiral Tailings
Issue 1, February 2006
UTILIZATION OF COAL FLY ASH FOR THE PRODUCTION OF ARTIFICIAL AGGREGATES AS A CROP GROWTH MEDIUM WITH ACIDIC “KUNIGAMI MAHJI” SOILS IN OKINAWA-JAPAN
G.Y. Jayasinghe* and Y. Tokashiki
Department of Environmental Science and Technology, Faculty of Agriculture
University of the Ryukyus, 1-Senbaru, Nishihara-Cho, Okinawa (903-0213)
The escalating world wide production of coal fly ash and its respective costs of disposing create an urgent need to find potential utilization methods in order to avoid disposal as land fillings. Development of synthetic light weight aggregates (SLWA) with coal fly ash and used paper can be regarded as an unconventional method for ash utilization which is being not much addressed. This study examined the properties of SLWA developed by coal fly ash ,used paper and starch as a binder and their utilization as a soil amendment to improve the crop production in acidic ,low productive `Kunigami Mahji` soils in sub tropical Okinawa, Japan.
Produced aggregates showed high levels of stability, strength and water holding capacities. . Moreover heavy metal contents in aggregates were analyzed and found to remain well below the permissible level. SLWA, which had the highest aggregate stability and strength (i..e. produced at 20% level of starch application) were used as an amendment to improve the crop production in `Kunigami Mahji` soils. Aggregates were mixed in 6 proportions with `Kunigami Mahji` soils at the percentages of 0 % ( 100 % soil), 10%, 25%, 50%, 75% and 100 % ( 100% SLWA) in a pot experiment. Komatsuna, which is called Japanese mustard spinach (Brassica rapa Var. Pervidis), was used in the experiment. It is evident that aggregate mixing percentage up to 25% with `Kunigami Mahji` soils, was the best mixing percentage which gave the maximum yield . Moreover SLWA addition as a soil amendment significantly enhanced physical and chemical properties of“Kunigami Mahji` soils. Therefore, this study demonstrates that coal fly ash together with used paper can be used to produce synthetic light weight aggregates, which can be utilized to improve the crop production in low productive `Kunigami Mahji `soil as a soil amendment . Moreover this SLWA production can be recommended as an effective alternative method for fly ash disposal.
Keywords: Aggregate stability, Aggregate strength, Coal fly ash, `Kunigami Mahji` soils, Synthetic light weight aggregates (SLWA).
TECHNICAL EVALUATION OF WASTE COMPOSTING PLANT
M. El-Hoz, Ph.D.
Department of Civil Engineering
The University of Balamand
P.O. Box 100
The objective of this study is to evaluate the municipal solid waste composting plant which is implemented in Lebanon with a capacity of 300 tons per day of organic material. Samples from the compost produced were analyzed in the laboratory to check for quality assurance where standards for physical properties were set for this composting plant. Based on the results obtained, the moisture content was higher than the required limit. Therefore, review of the bottlenecks of the composting process should be made to improve the quality of the compost. The generated leachate during the fermentation and maturation processes is treated. The technique is based on biological treatment by aeration and physical / chemical treatment by flocculation and coagulation. The results indicate that the effluent quality is not meeting the original design parameters and the treatment process is ineffective. Therefore, a new plan for another process is needed. It can be concluded that composting of municipal solid waste can present more than 50% reduction of the total amount of solid waste generated. Moreover, apart from effecting resource recovery and reduced cost of ultimate disposal, to utilize MSW compost in the country, market-driven standards and regulations should be met.
Keywords: Composting; municipal solid waste; compost quality; marketing compost
USE OF DUST WASTE FROM GRAIN STORAGE FACILITIES FOR SOIL STABILIZATION AND MOISTURE RETENTION
Department of Civil Engineering
Phone: +96227201000 x 22126
Department of Biosystems Engineering
Phone: +96227201000 x 22341
Large amounts of dust waste are produced during loading and unloading of grains in the grain storage facilities. This powder-like material imposes a serious health hazard to workers as well as to neighboring communities. Reuse of this waste can be a feasible management option. This study investigates two possible uses of this grain dust waste: (1) to enhance the geotechnical properties of expansive soils and (2) increase the capacity of soils to retain moisture. Expansive soils constitute the most costly natural hazard to buildings and civil engineering structures. In order to stabilize these soils, grain dust waste was mixed with two local expansive soils from northern Jordan at different percentages ranging from 0 to 8% by mass. The two soils from Irbid and JUST were classified as CH and MH, respectively, according to the Unified Classification System. The experimental work involved investigating the Atterberg limits, unconfined compressive strength, direct shear strength, standard Proctor density, and swell pressure. The results showed that the dust waste decreased the plasticity index, dry density, and the unconfined compressive strength. It was also found that the swell potential was reduced by up to 58% and the swell pressure was reduced by up to 54% to 75% with the upper range limits corresponding to the Irbid soil. Slow direct shear tests indicated that the stabilizing agent decreased the cohesion intercept while the angle of internal friction was increased by up to 19% to 45%. The findings of this study indicate that the use of grain dust waste is promising as a soil stabilizer and is a viable option of material utilization. The capacity of both soils to retain moisture under suction pressures ranging from 0 to 15 bars was tested in a pressure plate extractor. Moisture retention capacity increased significantly when 4 and 8% of grain dust waste were mixed with these soils at all pressures. Irbid soil had higher moisture retention capacity than JUST soil. The grain dust waste has a potential application for preserving moisture in agricultural soils. The addition of 8% of grain dust waste to soil will not have adverse effects on the quality of the water leaching through the dust waste-soil mixture. Similar pH and EC values were measured in two solutions containing soil-grain dust waste mixture and soil only.
Keywords: Grain dust waste, Expansive soils, stabilization, moisture retention
DEVELOPMENT AND ANALYSIS OF WEAR RESISTANCE MODEL FOR COMPOSITES OF ALUMINIUM REINFORCED WITH RED MUD
Department of Mechanical Engineering
National Institute of Technology, Rourkela-769008, INDIA
Fax: 91-0661-246-1169, 91-0661-246-2999
Department of Mechanical Engineering
Gandhi Institute of Engineering & Technology, Gunupur-765022, INDIA
Department of Mechanical Engineering
National Institute of Technology, Rourkela-769008, INDIA
The expeditious advancement in the past decades has resulted in the need for new multifunctional materials that possess characteristics not obtainable from any individual materials. Recent studies reveal that metal matrix composites reinforced by SiC and Al2O3 particles, whiskers and soft fibers, have significantly better characteristics such as super wear resistance, high strength and low density than unreinforced materials. However, prohibitive costs and stability of properties pose challenge for the researches in the process of development of composites. To address these issues, composites are being developed using waste materials as reinforcement for effective utilization of industrial wastes.
The present investigation aims to evaluate the wear characteristics of Al alloy composites reinforced with red mud in different volume percentage using Taguchi method. A pin-on-disc wear testing machine was used to evaluate the wear rate. In order to identify important factors that accelerate wear rate, an experimental design based on L27 orthogonal array is used. The response is transformed to signal to noise (S/N) ratio for smaller is better condition and analysis of variance is employed to interpret the results. The experimental results show that applied load, sliding distance and interaction between applied load and sliding distance have major contribution of wear rate. But few other interactions like reinforcement size and applied load and reinforcement size and sliding distance does not exhibit any significant effect on wear rate. Finally, a predictive model for wear rate of composites is developed. The confirmation experiment results in a good agreement between the predicted and actual wear resistance.
Keywords: Metal Matrix Composite; Red Mud; Taguchi Method
INFLUENCE OF CONTAMINANT SOURCE NODE SPACING AND DISPERSIVITY ON DETECTION CAPABILITY OF GROUNDWATER MONITORING NETWORKS
Paul F. Hudak
Department of Geography, University of North Texas
P.O. Box 305279
Denton, TX 76203-5279
Telephone: (940) 565-4312
Effects of contaminant source node spacing and dispersivity on the detection capability of groundwater monitoring networks were evaluated. The analysis considered five-, seven-, and nine-well networks near a rectangular landfill located 100 m from a buffer zone boundary, a distance limit within which contaminants should be detected. Various combinations of source node spacing, longitudinal and transverse dispersivity, and contaminant source width were input to a computer model, which computed the detection capability of groundwater monitoring networks. Varying contaminant source node spacing from 1 to 10 m had little effect on the capability of monitoring networks to detect contaminants released from the landfill. Similarly, over a range of 0.2 to 10 m, longitudinal dispersivity had little effect on the detection efficiency of any monitoring network. By contrast, changing transverse dispersivity had considerable effect on detection capability of monitoring networks. For a longitudinal dispersivity and contaminant source width of 1 m, increasing transverse dispersivity from 0.1 to 0.2 m increased detection efficiency by 8 to 20%. This study suggests that transverse dispersivity should be carefully evaluated for site specific-conditions, and groundwater monitoring strategies should emphasize uncertainty in this parameter.
Keywords: Landfill, groundwater monitoring, source node, dispersivity
HEAVY METALS IN FLY ASHES: POTENTIAL IMPACT ON FLY ASH DERIVED COAGULANTS
Maohong Fan, Robert C. Brown & Yonghui Shia
Center for Sustainable Environmental Technologies, Iowa State University
J(Hans) van Leeuwen
Department of Civil, Construction and Environmental Engineering, Iowa State University
Ames, Iowa, 50011 USA
This research analyzed the distribution of fifteen trace elements from thirty-two fly ash samples collected from four countries. The inductively coupled plasma/ mass spectrometry analyses of acid extracts show that concentrations of heavy metals in fly ashes vary from one country and power plant to another. Coagulants produced from these fly ashes need to be analyzed and tested to prevent levels of heavy metals that are higher than desirable in wastewaters treated with these.
Keywords: Coal; Fly ash; Trace Elements; Contaminants