Issue 4, November 2008
CO-COMPOSTING OF OLIVE MILL SOLID WASTE AND CHICKEN MANURE
Bassim Eid Abbassi, Ph.D.
Al-Balqa’ Applied University
19117 Al-Salt, JORDAN
The massive amount of solid residues from the agroindustries causes serious environmental problems due to their high organic content. Chicken manure and olive mill solid residues (pomace) are usually applied in agriculture or disposed of without any further treatment causing serious environmental problems especially in hot weather. Co-composting of these solid residues has been studied as a new innovative method. Composting was carried out at different C/N ratios ranging from 20 to 35 and started by addition of water to reach a moisture content of 60%. A brief thermophilic period was observed 3 days after starting composting with a maximum developed temperature at the centre of the material of 65 �C. Subsequently, the temperature maxima declined and did not exceed 35 �C after the first four weeks of composting. The experiments showed clearly that the optimum C/N ratio of the composting material was between 25 and 30. This conclusion was also based on the proposed weighing indicator equation for composting maturation.
Keywords: Co-composting; olive residue; chicken manure; maturation index; ultimate analysis; proximate analysis
CONTAMINATION OF SOLID WASTE FROM TOXIC MATERIALS IN ELECTRONIC WASTE (E-WASTE)
Sunil Herat, Ph.D.
Senior Lecturer, Griffith School of Engineering
Nathan Campus, Griffith University, Queensland 4111, AUSTRALIA
Tel: +61 7 3735 6682
Electronic waste or e-waste is the fastest growing and the latest waste stream in global waste sector. Ever increasing demand for electrical and electronic equipment (EEE) such as computers, mobile phones, televisions, washing machines, refrigerators in our modern society coupled with wide availability of latest designs in the electronics industry lead to rapid obsolescence of EEE well before their end-of-life use. Apart from the significant number of EEEs entering the global stream, the toxicity of certain materials contained in them is major concern to waste managers. E-waste contains more than 1000 different substances out of elements such as lead, mercury, cadmium, hexavalent chromium and brominated flame retardants are of major threat to human health and the environment. Regulations are being developed or implemented in many countries around the world to ban or restrict above materials from EEE. This paper investigates the use and toxicity of materials used in the manufacture of EEE that could contaminate the solid waste streams.
Keywords: Electronic waste; E-waste; Lead; Brominated flame retardants, Hexavalent chromium
MANAGING E-WASTE—A REUSE STRATEGY FOR UK COMPUTERS TO FACILITATE DEVELOPMENTS IN THIRD SECTOR ORGANIZATION COMPOSTING IN CAMEROON
Margaret Bates, Lawrence O. Mbeng, Paul S. Phillips
SITA Centre, University of Northampton
Northampton NN2 7AL, United Kingdom
While there has been much debate in the past as to the banning of e-waste being exported to Africa, the new paradigm today is with the reuse of this e-waste to enhance Africa’s economic and social development. This paper highlights some of the setbacks underpinning the importation of e-waste into Africa from existing legislation, which has incessantly widened the gap between the haves and have-nots of information technology. Based on these, the paper presents a snapshot of a 5 year pilot project for the reuse of second computers from the UK to Cameroon with the aim of driving sustainable practices in the composting of household organic waste and hence create new markets in Limbe and Douala -Cameroon through education and capacity building.
Keywords: E-waste; legislation; reuse; composting; education; capacity building
STUDY OF SOME PERFORMANCE PARAMETERS OF AN ATMOSPHERIC BUBBLING FLUIDIZED BED BOILER BASED ON COAL WASHERY REJECTS CONSIDERING BUBBLE GROWTH ALONG BED HEIGHT
S. K. Mohapatra
Professor and Head, Department of Mechanical Engineering
Thapar University, Patiala, Punjab, INDIA
Ravi Inder Singh
Lecturer, Department of Mechanical Engineering
Guru Nanak Dev Engineering College, Ludhiana, Punjab, INDIA
The increasing problem of the disposal of solid wastes has presented many cities with a dilemma while choosing suitable disposal methods. The traditional means of disposal of solid wastes like coal washery rejects and middling, municipality waste, rice husk, saw dust etc. have been open dumping, land filling or dumping in the sea. These practices have been discouraged due to non availability of land and new environmental legislation. Incineration, has, therefore been identified in several studies to play an important role in future as disposal for solid waste. In India, fluidized bed combustion technology is gradually emerging as a potential technology for the incineration of solid wastes like washery rejects and middling, rice husk, saw dust, and municipality wastes etc. A number of small scale fluidized bed combustion power plants have been commissioned in the recent past as a result a large amount of data is available for modeling and simulation. A mathematical model has been developed for the exit-gas composition in a 10 MW atmospheric fluidized bed boiler in which coal washery rejects are being incinerated at Jamadoba, India. The model allows for bubble size variation with height and predicts the composition of outlet gas composition. Model predictions are compared with plant data and reasonable agreement is obtained.
Keywords: Three phase model, bubble growth, exit gas composition
FUZZY LOGIC MODELING OF BIODEGRADATION OF MUNICIPAL SOLID WASTE UNDER AEROBIC AND ANAEROBIC SIMULATED BIOREACTORS LANDFILL
Septa Rendra and Leta Fernandes
Department of Civil Engineering, University of Ottawa
161 Louis Pasteur Street, P.O. Box 450, Stn. A
Ottawa, Ontario K1N 6N5, CANADA
Mostafa A. Warith
Department of Civil Engineering, Ryerson University
350 Victoria Street, Toronto, Ontario M5B 2K3, CANADA
A fuzzy logic model was developed to simulate biodegradation of municipal solid waste (MSW) in simulated bioreactors landfill under aerobic and anaerobic conditions. The bioreactors were operated to determine the amount of leachate recirculation and municipal wastewater sludge addition required to optimize waste biodegradation. The leachate generated was recycled over 47 and 63 weeks, leachate samples were collected on a weekly basis and analyzed for chemical oxygen demand (COD). The temperature of the MSW in the bioreactors was measured on a daily basis. Leachate and sludge were added at the rates of 5 L/wk to 15 L/wk and 0.5 L/wk to 1.5 L/wk, respectively. Within 27 and 41 weeks for aerobic and anaerobic bioreactors, enhanced MSW degradation was observed at a leachate recirculation rate of 15 L/wk (855 mL/kg of MSW/d) and sludge addition rate of 1.5 L/wk (85 mL/kg of MSW/d). During this period, the COD concentration in the leachate dropped from 38,000 and 45,000 mg/L to approximately 1000 mg/L for aerobic and anaerobic bioreactors, respectively. Reduction in the leachate recirculation and sludge addition rate to 285 and 28 mL/kg of MWS/d respectively, increased the waste stabilization period up to 45 and 63 weeks for aerobic and anaerobic bioreactors. Within 10 and 25 weeks in aerobic and anaerobic bioreactors, temperatures reached the peak at 56 and 38 0C at a leachate recirculation rate of 855 mL/kg of MSW/d and sludge addition rate of 85.5 mL/kg of MSW/d). Based on the two parameters, COD and temperatures, fuzzy logic approach was employed to develop a MSW biodegradation model. The results obtained from the fuzzy logic simulation demonstrated reasonable agreement with the experimental observations. Although there were deviations between the model simulation and measured data, the simulation results can closely predict the trend of the MSW biodegradation process. The overall evaluation of the simulation also confirmed the efficiency and reliability of the model to reproduce pertinent characteristics and important features of MSW biodegradation under leachate recirculation and sludge addition with or without air addition. Accordingly the MSW biodegradation process can be accurately simulated using the fuzzy logic control approach.
Keywords: Municipal solid waste; aerobic and anaerobic bioreactors; leachate recircuation; sludge addition; fuzzy logic simulation
USE OF PRECIPITATION DATA TO DEVELOP AND MODIFY THE LEACHATE MODEL FROM SMALL-SCALE LANDFILL OF MSW COMBINED WITH INCINERATION ASHES
Department of Environmental Engineering, Vanung University
Chungli, Taoyuan 32045, Taiwan
Tel: 886-3-4515811 ext. 23000; Fax: 886-3-4622232
Department of Environmental Engineering, Vanung University
Chungli, Taoyuan 32045, Taiwan
The principal purpose of this study is to explore the influences that adsorption, desorption, and biological reactions may have on leachate quality from landfill. The disposal site of MSW combined with incineration ashes is simulated by two outdoor pilot-scale lysimeters, assuming that an incinerator had treated 60% and 90% of MSW respectively. The incineration ashes would be disposed with MSW surplus. The characteristics of incineration ashes disposal can be determined by comparing the experimental results. Since these parameters were obtained in a laboratory rather than under actual conditions, the relationship between these parameters and precipitation should be considered. These parameters must be modified by natural conditions such as precipitation in order to obtain the characteristics under actual environment. Based on the model established by the authors (2000,2001)[1,2], the modification and exact model of leachate from the landfill of MSW combined with incineration ashes is thus established. The leachate quality is approximately similar to the experimental data and the simulation results.
Keywords: Landfill, leachate model, incineration ashes, pilot scale lysimeters test, adsorption, desorption
Issue 3, August 2008
MUNICIPAL SOLID WASTE TREATMENT AND RECYCLING TECHNOLOGIES FOR DEVELOPING COUNTRIES — A TYPICAL NIGERIAN CASE STUDY
Chidubem Uchendu, M.Sc.
Fachhochschule (University Of Applied Sciences)
Menso – Alting Strasse 33, D – 26721, Emden GERMANY
Nigeria is a land endowed with abundant human and natural resources. These natural resources are converted to waste by anthropogenic causes. Each year, about 5.9 million tonnes of municipal solid waste is generated in Nigeria. This is not unusual. The only problem is in the way these wastes are handled. Most of them are dumped indiscriminately in open and unsecured landfills or water bodies. Some are even burnt openly without energy recovery.
The entire situation has been critically examined and practical solutions proffered. A sustainable system where the disposal of household wastes is organized from homes (where they are produced) to the point where they are recovered (material and energy) was carefully outlined.
The short and long term effects and consequences were also discussed. Finally, mention is made of how this process will, in the long run, systematically lead Nigeria, and indeed other developing countries, to sustainability as outlined in “AGENDA 21” (Global Partnership For Sustainable Development).
Keywords: Nigeria; municipal solid waste (MSW); disposal of household wastes; material recovery; energy recovery; developing countries; AGENDA 21; sustainable development
IS RECYCLING GARBAGE? — THE REPORT OF A PILOT STUDY AT BARRY UNIVERSITY, MIAMI, FLORIDA
Anita Z�vodsk�, Ph.D.
Assistant Dean for Academic Affairs
Assistant Professor of Environmental Sciences
School of Adult and Continuing Education, Barry University
8001 S.W. 36th Street, Suite #1
Davie, FL 33328
Tel.: (305) 981-5224
The battle against contamination in material recycling is an on-going one, and therefore, it was not unfamiliar in a pilot recycling project that was conducted at the Doral off campus-site of Barry University’s School of Adult and Continuing Education (ACE). In mid-January 2003, two well-labeled recycling bins, set visibly apart from the garbage receptacle, were placed in the three classrooms at the Doral site. One bin was strictly for office paper, while the other was for drinking containers made of plastic (#1 and #2 only), glass and aluminium. The bins were emptied weekly for a seven-week period, and the weight and composition of the collected materials were noted. The weight and composition of the garbage were also noted for comparison. The purpose of this study was to characterise and analyse the site’s waste stream, and to then, use the collected data in the institution of a formal method of recycling, where the useful materials would be hauled away by a commercial entity because at the time of the study, no recycling was being done at the site. If this were proven to work efficiently at Doral, then, in time, the goal would be to institute similar programmes at ACE’s fourteen other off-campus sites throughout the state of Florida.
Keywords: Off-campus recycling; waste characterisation; pilot project, university recycling; material contamination
HEAT RECOVERY OPPORTUNITIES FROM A GRAIN DUST COMPOSTING PILE
Mohamad Al-Widyan, Associate Professor
Majdi Al-Mahasneh, Assistant Professor
Hussain Ababneh, Assistant Professor
Department of Biosystems Engineering
Jordan University of Science and Technology (JUST)
P.O. Box 3030, Irbid 22110
In Jordan, large proportions of both the NGP and hard currency go for imported energy. Meanwhile, large quantities of grain dust are continuously produced locally and dumped uselessly. Thus, this study was set out to examine the opportunities of heat energy recovery from a composting pile of grain dust. Amounts of the material were arranged in piles with passive and forced aeration schemes and measurements of their temperature and heat transfer rates to water and air were made. It was found that the two small laboratory scale piles effected significant rise in water and air temperature of up to 35 oC above the ambient and a rate of heat transfer in the range of up to 600 Js-1/m3 during the test periods for up to 30 days. It was also found that under local prevailing climatic conditions, pile moisture deceased relatively quickly below the minimum optimal levels calling for relatively frequent wetting of the aerated and insulated piles.
Keywords: Organic solid wastes, Grain dust, Heat recovery, Composting
PREDICTION OF THE HYDRAULIC CONDUCTIVITY OF CLAY LINERS FOR EFFICIENT CONSTRUCTION AND MONITORING OF CLAY LINERS IN LANDFILLS
Frank Atuahene, Ph.D., M.ASCE
Georgia Southern University
Department of Construction Management and Civil Engineering Technology
Carruth Building, Forest Drive, P.O. Box 8047
Statesboro, GA 30460
The hydraulic conductivity or coefficient of permeability is the most important property of compacted clay in the design of waste containment structures such as landfills. The geotechnical engineering profession has experienced difficulties over the years with the reliable prediction of hydraulic conductivity in the field. This study establishes a model for the prediction of the hydraulic conductivity of clay liners (compacted clay) based on its water content and dry unit weight. General linear and polynomial regression analyses were carried out on previously published data obtained from hydraulic conductivity tests on thirteen compacted clay soils used for clay liners at landfills throughout the United States to establish a model for predicting hydraulic conductivity with 95% confidence level. The consistency and accuracy of the proposed model with independent variables W (water content) and D (dry unit weight), Model WD, in predicting the hydraulic conductivity make it superior to existing models. The accuracy is measured by comparing hydraulic conductivity measured by a permeameter, (obtained from a publication by Benson and Trast, 1995), and that calculated using the model for the same sample of soil. With such a model, the hydraulic conductivity of clay liners could be predicted during and after construction without using lengthy and cumbersome methods.
Keywords: Clay liners, compacted clay, hydraulic conductivity, permeability, model prediction, landfills.
DRIVING THE WASTE PREVENTION AGENDA — AN EVALUATION OF WEIGHING KERBSIDE HOUSEHOLD WASTE ARISINGS METHODOLOGY, IN DORSET, UK
Mike Read Associates
Marten K. Gregory
Waste Management Division, Dorset County Council
County Hall, Dorchester, DT1 1XJ, UK
Paul S. Phillips
SITA Centre, University of Northampton
Northampton, NN2 7AL, UK
Household waste prevention in England has been recognised in national strategy as a key component for future sustainable practice. To support the policy agenda, the Department of Environment, Food and Rural Affairs (Defra) in England has funded an extensive programme of fundamental research in the area. Previous attempts to assess the impacts of waste prevention initiatives have faced a number of problems. These have generally centred on difficulty in separating the effects of initiatives from external factors and inadequate sample sizes or methodology. The specific research aim reported on here, in this Defra funded project, was to trial and assess methods for monitoring and evaluating approaches detailed in the National Resource and Waste Forum (NRWF)’s Household Waste Prevention Toolkit. The primary objective of this research was to quantify the direct waste tonnage impacts of implementing a targeted household waste campaign in Dorset. The key performance indicator chosen for this assessment was the weight of waste collected at the kerbside from households. The results are informative and will help future teams design campaigns on the basis of rigorous methodology. It was found that there are a wide range of factors that need to be taken into account and that had hitherto been given little prominence, such as careful matching of pilot and control areas. Analysis of the results leads to the conclusion that waste arisings for residual waste has decreased in the pilot area (≈ 10.5%) more than the controls (e.g. ≈ 5.5%). This method for monitoring can be used, in the hands of an expert project team, to communicate to the public the direct benefits of waste prevention.
SIMULATION OF LEACHATE PRODUCTION FROM AN ARID SOLID WASTE LANDFILL USING HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE (HELP) MODEL
Hani Abu Qdais, Fayez Abdulla, and Luay Qrenawi
Civil Engineering Department, Jordan University of Science and Technology
P.O. Box 3030, Jordan, Irbid
Landfill leachate is a byproduct of the landfilling process. Unless properly managed, leachate will lead to several adverse environmental and health impacts. In arid regions where precipitation amounts are low, the perception is that leachate generation is minimal. Therefore, leachate generation has been neglected and not given the required attention. However, evidence from field practices show that arid landfill leachate may be a significant problem that should be considered.
The present study is an attempt to quantify the leachate generated at an arid landfill located in Rafah (Gaza Strip) using the Hydrologic Evaluation of Landfill Performance (HELP) model. Input parameters that are subjected to high variability and significantly affected the amount of leachate produced were identified. Simulation process revealed that the most significant factors affecting the model predictability in arid region are the evaporative zone depth and the maximum leaf area index. Calibration and optimization process revealed that the optimal values of the two parameters are 60 cm for the evaporative zone depth and 0.85 for the maximum leaf area index, respectively. Sensitivity analysis shows that the two parameters are affecting the simulation results with various degrees, with evaporative zone depth impact being the greatest.
Keywords: HELP model, leachate, maximum leaf area index, evaporative zone depth, arid landfills
Issue 2, May 2008
ANALYSIS OF ELEMENTAL COMPOSITION OF SOLID INDUSTRIAL WASTES AND ITS USE FOR THE ASSESSMENT OF REUSE/RECYCLING OPTIONS
T. Seyoum and S.B. Adeloju
School of Applied Sciences and Engineering, Monash University
Gippsland Campus, Churchill, Vic 3842
A reliable approach is described for the analysis of the chemical composition of Solid Industrial Wastes (SIW) from liquid waste treatment plants by a range of analytical techniques. X-ray Fluorescence (XRF) analysis was used to obtain a general composition of inorganic analytes in the SIW and then followed by detailed analysis of major elements and most heavy metals by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Mercury was determined by ICP-VGA (Vapor Generation Analysis) throughout the sampling period. TCLP tests were conducted on treated filter cake and stabilized sludge to determine the concentrations of leachable heavy metals. XRD analysis was also conducted to identify the types of phases present in both waste streams. Comparison of the chemical composition of the treated SIW is made against EPA Victoria regulatory requirement for hazard classification. The potential use of the treated SIW for the development and implementation of innovative reuse/recycling management options is discussed.
Keywords: Solid industrial wastes, Sludge, Heavy metals, Mercury, TCLP
RECYCLING OF BAGASSE ASH IN THE RAW MIX DESIGNING AND CLINKERIZATION OF HIGH STRENGTH PORTLAND CEMENT AS A RAW MATERIAL AND ITS IMPACT ON CLINKER POTENTIAL AND FUEL CONSUMPTION
Khurshid Ali, Noor-ul-Amin , and Yousaf Iqbal
Institute of Chemical Sciences, University of Peshawar
M. Tahir Shah
National Center of Excellence in Geology, University of Peshawar
Bagasse ash from sugar mills of the North West Frontier Province (NWFP) has been used in the raw mix designing for high strength Portland cement and subjected to clinkerization. The clinker was converted into cement, and different parameters of the resulting clinker and cement were studied and compared with the British and Pakistan standard specification. It has been found that bagasse ash can be utilized in the raw mix up to 5% only, above which the chemical and physical parameters of the resulting clinker and cement are disturbed. With addition of 5% Bagasse ash, 6.46% energy is saved, while emission of carbon dioxide to the environment is decreased up to 1.73%. The use of 5% Bagasse ash replaces clay up to around 5%.
SEISMIC VELOCITY ANALYSIS TO DETERMINE MOISTURE DISTRIBUTION IN A BIOREACTOR LANDFILL
Department of Civil and Environmental Engineering, Carleton University
1125 Colonel By Drive Ottawa, Ontario K1S 5B6, CANADA
Department of Earth Sciences, Carleton University
1125 Colonel By Drive Ottawa, Ontario K1S 5B6, CANADA
P.J. Van Geel
Department of Civil and Environmental Engineering, Carleton University
5 Colonel By Drive Ottawa, Ontario K1S 5B6, CANADA
To establish an effective leachate recirculation process, the moisture distribution within a landfill must first be estimated so that leachate can be added appropriately to create optimal and homogeneous moisture conditions throughout the waste mass. Seismic surveys were conducted at a bioreactor landfill in Ste-Sophie, Quebec, Canada, with the objective of mapping the moisture distribution using seismic data collected from the surface of the landfill. Analysis of the travel times of direct and refracted seismic waves established that the landfill is structured as a 4.5 m upper layer of loose waste and a 25.5 m lower layer of compacted waste with average compressional wave velocities of 280 m/s and 380 m/s, respectively. Seismic velocity analyses indicated that an increase in moisture content, caused by leachate injection, increased the compressional wave velocity of waste. Specifically, the injection of approximately 1m3 of leachate per meter length of trench through two recirculation trenches caused an increase on the order of 22 m/s (7 %) in the stacking velocity of the compressional waves reflected off the landfill bottom. The lateral radius of influence of the injected leachate was 5 m-10 m and the velocity results reached steady state approximately 3 hours after the injection ceased.
Keywords: Bioreactor landfill, Moisture content, Seismic surveys, Velocity analysis, Compressional wave (P-wave) velocity, Seismic reflections
METHODOLOGY DEVELOPMENT FOR FUTURE DECISION MAKING — OPPORTUNITES FOR NON-MUNICIPAL WASTE FACILITIES IN NORTHAMPTONSHIRE, ENGLAND
Margaret P. Bates, Nigel P. Freestone, Paul S. Phillips and Terry L. Tudor
SITA Centre, University of Northampton
Northampton, UK NN2 7AL
SLR Consulting Ltd.
Rowden Lane, Bradford on Avon, UK BA15 2AU
Land use planning for facilities has become a key issue in England as previously, prolonged disputes in proceedings, due to public opposition, has meant that waste management facilities have taken an excessive period of time to be completed and start operating. This research identifies the impact of relatively recently introduced Regulations on the possible development of new non-municipal wastes management facilities in Northamptonshire, an English County in the East Midlands of England. The results of the research will help provide guidance to policy makers and planners at all levels so as to enable them to make informed decisions on the selection and funding for possible new facilities, based upon a number of management options. The results show that for some management routes there is the likely future demand for a number of additional new facilities that are on a local, County scale e.g. Waste Electrical and Electronic Equipment (WEEE). In other cases, there is no clear demand for future expansion e.g. Hazardous Waste facilities.
Keywords: Regulatory Impact Assessment, Non-Municipal Facilities, Opportunities Analysis, Spatial Options Development
BIO COMPOSTING OF LEAF LITTERS BY EUDRILUS EUGENIAE AND ITS APPLICATION ON THE GROWTH OF GREEN GRAM (VIGNA RADIATA (L) CO. 6)
S. Jayashree, J. Rathinamala, and P. Lakshmanaperumalsamy
Department of Environmental Sciences, Bharathiar University
Coimbatore – 641046, INDIA
Phone: + 91 422 2424729
The present investigation of preparing vermicompost from different organic wastes (leaf litters, tea wastes, vegetable wastes and fruit wastes) using Eudrilus eugeniae has shown evidence for positive participation of earthworm in biocomposting. [The vermibeds were prepared with cow dung (CD) and organic wastes in the ratio of 1:1 and 1:2 with appropriate control. The vermicompost were analyzed for pH, EC, Organic carbon (OC), N.P, K and C/N ratio. When compared with tea, vegetable and fruit wastes vermicompost, the leaf litters vermicompost showed higher N, P and K. The OC and C/N ratio decreased significantly during maturation of the compost in 1:1 and 1:2 ratios. The pot culture studies on the germination, growth and yield performance of Vigna radiata (L) CO 6 with vermicompost were significant.]
Keywords: Biocomposting, Eudrilus eugeniae, Vigna radiata, Ficus indica
APPLICATION OF GEOGRAPHICAL INFORMATION SYSTEM FOR SANITARY LANDFILL SITE SELECTION
M. El-Hoz, Ph.D.
Department of Civil Engineering, The University of Balamand
P.O. Box 100, North Lebanon
The objective of the study is to apply the Geographical Information System (GIS) as a potential tool to identify the most suitable locations for a new sanitary landfill within the Municipal Union of Al-Koura. Criteria used have been identified based on the guidelines produced by the Ministry of Environment and some additional constraints. The GIS maps (scale 1: 25,000) of topography, roads, soil, surface and groundwater, geology, buildings, and aerial photo of Al-Koura district were prepared and used for site selection. As for the operating system Windows XP and for the software, the packages ARCGIS 8.2, and ARCVIEW 8.2 were used. The site selection study has identified 6 potential areas for sanitary landfill sites. Based on the criteria, the GIS spatial operation using map layers worked very well using the ArcView 8.2. Moreover, three additional constraints were applied to narrow the potential land areas after sites visits such as the presence of fault, severe topography and access road. The final decision will be made on appropriate ranking techniques for the determination of a new landfill site since it has something to do with political decision, management issues and budget allocation.
Keywords: Municipal solid waste, landfill site selection, Geographic Information System (GIS), ARCGIS 8.2, and ARCVIEW 8.2
Issue 1, February 2008
STUDY ON THE QUALITY OF RICE HUSK ASH AT DIFFERENT FLUIDIZING VELOCITY IN A FLUIDIZED BED COMBUSTOR
M. Rozainee, S.P. Ngo, A.A. Salema, & K.G. Tan
Department of Chemical Engineering
Faculty of Chemical and Natural Resources Engineering
Universiti Teknologi Malaysia, Skudai
UTM 81310, Johor Darul Ta’zim
Rice husk ash has a rigid skeleton-like structure due to its high silica content, resulting in a considerable amount of carbon being trapped in the skeleton and cannot be burned or gasified easily. This study was focused on investigating the quality of rice husk ash at different fluidizing velocity during the combustion of rice husk in a fluidized bed combustor (ID 210 mm). When all other parameters are held constant, the optimum fluidizing velocity aids in almost complete combustion, thereby releasing the entrapped carbon for further conversion. This results in ash with consistently low carbon content (less than 2 wt%). The range of fluidizing velocities investigated was from as low as 1.5 Umf to as high as 8 Umf. It was found that the optimum fluidizing velocity was approximately 3.3 Umf as the mixing of rice husk with the bed was good with a high degree of penetration into the sand bed. The resulting ash was fine in size and retained its amorphous form with low residual carbon content (at 2.88 wt %) and minimal sand contamination as shown by the x-ray diffraction analysis.
Keywords: Fluidized bed, Fluidizing velocity, Rice husk ash, Residual carbon, X-ray diffraction analysis
REGENERATION OF DIFFERENT TYPES OF GRANULAR ACTIVATED CARBONS WITH ADSORBED TRICHLOROETHYLENE USING WET PEROXIDE OXIDATION
Kiyokazu Okawa, Toshihiro Takeshita and Katsuyuki Nakano
Institute for Recycling and Environmental Control System
10 Koyomachi, Wakamatsu-ku, Kitakyushu 808-0002
The objective of this study is to clarify the regeneration of different types of granular activated carbons (GAC) with adsorbed trichloroethylene (TCE) using wet peroxide oxidation (WPO) under mild condition (180�C). TCE adsorbed on each GAC was degraded by WPO. The rate of TCE degradation was higher in GAC with larger pore size. In the repeated regeneration of GAC, the adsorption capacity of each GAC for TCE gradually decreased. Especially, the adsorption capacity of catalyzed GAC, CENTAUR (Calgon Mitsubishi Chemical Co.) decreased more than other GAC with regeneration efficiency (q/q0) of 0.17 in the 4th step using 6 hours regeneration time. On the other hand, the adsorption capacity of the largest pore size GAC, Diahope007 (Calgon Mitsubishi Chemical Co.), which has the fastest TCE degradation, did not decrease much in 2 hours regeneration time and the regeneration efficiency at 4th step was 0.93. Even though adsorption and regeneration was repeated, the BET surface area and pore volume of each GAC were not reduced.
Keywords: Granular activated carbon, hydrogen peroxide, pore size, regeneration, trichloroethylene, wet peroxide oxidation
CHEMICAL PRECIPITATION OF AMMONIA-N AS STRUVITE FROM LANDFILL LEACHATE—EFFECT OF MOLAR RATIO UPON RECOVERY
Obuli P. Karthikeyan1, Research Scholar
Kurian Joseph2, Assistant Professor
Centre for Environmental Studies, Anna University
Chennai – 600 025
1Phone: +91-44-22301283, Email: email@example.com
2Phone: +91-44-22301283, Email: firstname.lastname@example.org
Struvite precipitation has the potential for removing ammonia-N from landfill leachate. A laboratory scale study was performed to investigate the recovery of NH4+-N as struvite using MgCl2.6H2O and Na2HPO4 as Mg and P sources, respectively. Seven different molar ratios (Magnesium: Ammonium: Phosphate) were used to optimize the removal efficiency of ammonia-N. Around 58% of ammonia removal was obtained in 1:1:1 molar ratio. Maximum removal efficiency of 76 and 78 % achieved at the molar ratio of 2:1:1.5 and 1.5:1:2, respectively. Leachate pH varied from 6.5 to 6.9 in supernatant samples obtained from different molar ratio. Leachate COD increased (from 3,461 mg/L to 10,481 mg/L) and TOC decreased (from 2,448 mg/L to 1,825 mg/L) with ammonia removal in leachate. Leachate quality in terms of calcium, potassium, nitrate, nitrite and phosphates were unaffected by the struvite precipitation.
Keywords: Landfill leachate, leachate treatment, ammonia-N, Chemical Precipitation, Magnesium Ammonium Phosphate (MAP) and Recovery
MODELING LANDFILL GAS GENERATION TO DETERMINE TARGETS AND STRATEGIES TO REDUCE GREENHOUSE GASES FROM LANDFILLS
Shirley Thompson1, Jennifer Sawyer2, Rathan Kumar Bonam1, and Stephen Smith1
1 Natural Resources Institute, University of Manitob
70 Dysart Road, Winnipeg, Manitoba, CANADA R3T 2N2
Phone: 204-474-7170; Fax: 204-261-0038, Email: email@example.com
2 Faculty of Environment, Earth and Resources, University of Manitoba
440 Wallace Building, Winnipeg, Manitoba, CANADA R3T 2N2
Phone: 204-474-7170; Fax: 204-261-0038, Email: firstname.lastname@example.org
The future impact of different waste management policies on greenhouse gas (GHG) emissions from landfills was estimated using the Scholl Canyon methane generation model. This scenario modeling provided a useful decision-making tool to determine appropriate targets for reductions in emissions and strategies to reach feasible goals. At low rates of 25% total waste diversion in Canada, the GHG emissions continue to rise due to historical organic waste emitting methane for 30 years to 50 years following landfill closure at higher rates than is reduced by organic diversion. At diversion rates of 50%, which is less than that already occurring in Prince Edward Island, GHG emissions decreased slightly. If 75% of total waste is diverted, which occurs in most European Union countries, a 30% reduction of GHG would result after 25 years. Waste diversion has a gradual impact on GHG: composting, recycling and extending producer responsibility provide the long-term solution to reduce GHG production and waste generation. However, diversion does not prevent emissions from waste already in place. “End-of-pipe” methane recovery technology burns methane from historical waste, decreasing GHG to create alternative energy, preferably, or by simply flaring the methane. Both methane recovery and waste diversion should be pursued to maximize GHG reduction.
Keywords: Scholl Canyon model, Greenhouse Gas, Methane, Waste Diversion, Composting, Landfills
AN ASSESSMENT OF MODIFIED COMPOSTING BARREL FOR SUSTAINABLE ORGANIC WASTE MANAGEMENT IN BANGLADESH
M. Azizul Moqsud
Ph.D. Student, Department of Civil Engineering
Saga University, 1 Honjo Machi, Saga 840-8502, JAPAN
Email: email@example.com; Fax: 81-952-28-8189; Phone: 81-952-28-8627
M. Habibur Rahman
Professor, Department of Civil Engineering
Bangladesh University of Engineering and Technology, Dhaka-1000, BANGLADESH
Shigenori Hayashi, Professor and Director
Y. Jun Du, Associate Professor
Institute of Lowland Technology
Saga University, 1 Honjo Machi, Saga 840-8502, JAPAN
An assessment of the efficiency of a modified steel barrel, and comparison of its performance with the conventional barrel using as a composting reactor in Bangladesh are presented in this paper. To ensure quick and uniform aerobic digestion and to get rid of bad odor, two modifications were made on the conventional barrel by: (1) providing 0.0125 m diameter openings throughout the sides and (2) placing a 0.0254 m diameter perforated polyvinyl chloride (PVC) pipe in the middle portion of the barrel. The test results show that the volume of composting wastes became 70% and 50% of its original volume after and before the modification of the composting barrel, respectively after 4 weeks. Nutrients in the compost were comparable with those reported elsewhere and these were in more suitable range after the modification of the composting barrel. The carbon-nitrogen ratio (C/N) of compost was found in the ideal range (11-15) in the modified composting reactor but it was quite high (24-25) in the conventional barrel. No pathogenic bacteria were found in the compost, as the elevated temperature in the modified composting barrel destructed during composting. The benefit-cost ratio is more than 1 for a large scale composting project with the modified barrel. This modified barrel composting plant proves to be an efficient, eco-friendly, cost-effective, and nuisance-free solution for the management of organic solid wastes in Bangladesh.
Keywords: Aerobic digestion, barrel, bacteria, composting, chemical and microbial analysis, benefit-cost ratio
STABILIZATION OF BLUE MUSSEL (MYTILUS EDULIS L.) PROCESSING WASTE WITH Ca(OH)2
Thomas L. Gallant1,2, John A. MacLeod1, Robert Gordon2,
John Blanchard2, and Mark Grimmett1
1Agriculture and Agri-Food Canada, Crops and Livestock Research Centre
440 University Avenue, Charlottetown, PEI C1A 4N6
2Nova Scotia Agricultural College, Department of Engineering
P.O. Box 550, Truro NS, CANADA, B2N 5E3
Mussel processing waste (MPW) is often treated as landfill or casually applied to soil. Leachate and odour problems associated with even short-term storage make land application difficult. Work was initiated to examine MPW stabilization via addition of hydrated lime (Ca(OH)2) with effectiveness rated through degree of liquefaction, change in pH, and CO2 evolution. For assessment of liquefaction and pH, Ca(OH)2 was combined with fresh MPW at 1%, 5% and 10% (w:w) with control of no lime. For assessment of CO2 evolution, MPW with 2% Ca(OH)2 (w:w) was compared to fresh MPW, liquid fraction of MPW, and liquid hog manure. Materials were contained in 20 L plastic containers with variables measured after seven days. Liquefaction (g produced/litre of waste) was 89, 45, 7.5, and 0, for control, 1%, 5%, and 10% treatments, respectively. The 5% and 10% treatments had significantly higher pH (~11 and ~12) compared to the 1% and control treatments (both ~6.0). The lime-treated MPW emitted less CO2 (1.22 g L-1 d-1) than the fresh (2.95) and liquid (5.02) MPW. A small amount of added Ca(OH)2 can provide short-term stabilization of MPW and increase its usability for agriculture.
Keywords: Calcium hydroxide, hydrated lime, stabilization, mussel processing waste