Vol. 35, No. 2, May 2009

Solid Waste Management in Accra, Ghana—Anaerobic Digestion as an Appropriate Pretreatment Option Prior to Landfilling

Geotechnical Characterization of Coal Ashes from Sarawak for Bulk Utilization

The Solid Waste Analysis and Minimization Research Project—A Collaborative Economic Stimulus and Environmental Protection Initiative in Northwest Ohio, USA

Pyrolysis of Scrap Tire for Preparation of Activated Carbon

Prediction of Leachate Flow-Rate in a MSW Landfill Site Using Neural Networks Method

Leaching Studies and Metal Analysis of Fly Ash From Thermal Power Plant of India

 

SOLID WASTE MANAGEMENT IN ACCRA, GHANA—ANAEROBIC DIGESTION AS AN APPROPRIATE PRETREATMENT OPTION
PRIOR TO LANDFILLING

Bernard Fei-Baffoe

Department of Environmental Science, Faculty of Biosciences
Kwame Nkrumah University of Science & Technology, Kumasi, GHANA
Email: feibaffoe@yahoo.com

Gunter Busch
Chair of Waste Management
Faculty of Environmental Sciences and Process Engineering Brandenburg
University of Technology, Siemens-Halske-Ring 8, 03046, Cottbus, GERMANY
Email: busch@tu-cottbus.de
 

ABSTRACT

This paper presents an overview of the problems of solid waste management in an urban centre-Accra, Ghana and certain important issues that must be considered in order to achieve success. Despite privatizing garbage collection, with the view of improving waste management services, there is still a severe waste management crisis throughout many parts of the metropolis. More waste is generated than collected by the waste authority and this has resulted in a deficit of solid waste left in the environment. Also, the waste collected and hauled to the dumpsite is not treated resulting in leachate pollution and greenhouse gas emissions. Diseases known to be environmentally related as a result of poor solid waste management are common. A detailed description of the situation in the metropolis is presented. In addition, biological pretreatment option is proposed as a sustainable approach towards the solution of the solid waste problem in the metropolis.

Keywords: Solid waste, Problems, Anaerobic Digestion, Accra, Pretreatment, sustainable
 

GEOTECHNICAL CHARACTERIZATION OF COAL ASHES FROM SARAWAK FOR BULK UTILIZATION

Prabir K. Kolay and Tony Kismoor
Senior Lecturer and Former Undergraduate Student
Faculty of Engineering, Department of Civil Engineering
Universiti Malaysia Sarawak
94300 Kota Samarahan, Sarawak, MALAYSIA
Email: pkolay2001@yahoo.com
 

ABSTRACT

The utilization of the coal, for the generation of electrical energy, has been increased substantially from 4.2 to 13 million tones during the years 2000 to 2005 in Malaysia. As a result, it produces a large quantity of ashes as a by-product. The coal ash can be, and is being successfully used, for different applications e.g., a stabilizer of sub-grade and sub-bases in pavement construction; as a fill material; as a foundation material etc. But before utilization in different fields mainly as a bulk its physical and geotechnical properties (e.g., compaction, compressibility and shear strength) must be studied. The advantages of using coal ash as a bulk fill material include low cost, low unit weight, and good strength. However, not much attention has been paid locally to the characterization of the coal ashes and its utilization in Sarawak. Hence this paper describes some physical, chemical and geotechnical properties of coal ashes collected from Sejinkat Thermal Power Plant, Sarawak, Malaysia.

Keywords: Coal ash; Physical properties; Chemical properties; Compaction; Compressibility; Shear strength
 

THE SOLID WASTE ANALYSIS AND MINIMIZATION RESEARCH PROJECT—A COLLABORATIVE ECONOMIC STIMULUS AND ENVIRONMENTAL PROTECTION INITIATIVE IN NORTHWEST OHIO, USA

Matthew J. Franchetti
     Dept. of Mechanical, Industrial and Manufacturing Engineering, University of Toledo 2801 West Bancroft Street
Toledo, Ohio 43606, USA

ABSTRACT

In 1996, an innovative partnership between the Lucas County Solid Waste Management District and The University of Toledo, College of Engineering was formed to help improve environmental and economic conditions in Lucas County, Ohio, USA by providing no cost solid waste assessments to Lucas County manufacturers and businesses. Since the inception of the project, over 70 waste assessments have been completed, over 109,000 tons of solid waste has been identified for reuse, reduction, or recycling and over $3.1 million have been identified as potential cost savings for Lucas County business. The purpose of this paper is to provide a complete overview and framework of this program so that other institutions may learn from it and adopt similar concepts to help reduce solid waste generation and improve economic conditions in their regions. A focus of this paper is a discussion of a case study that details the process and results of a typical solid waste assessment conducted through the project. Also included in this paper is a discussion of the project’s background, a comparison to similar project’s between colleges and government agencies, and results and benefits of the program, and an overview of the opportunities and barriers to this type of research. The project demonstrates that through a cooperative effort and a creative alliance, businesses, governments, universities, and industries can work together to improve environmental quality, reduce waste, and improve profitability. The project also educates college students though practical, real-world environmental work experience and trains them to become future environmental leaders.

Keywords: Waste assessments, recycling, economic analysis
 

PYROLYSIS OF SCRAP TIRE FOR PREPARATION
OF ACTIVATED CARBON
 

C. Srinivasakannan
Monash University, Sunway Campus
46150 Petaling Jaya, Selangor Darul Ehsan, MALAYSIA
Email: chandrasekar.srinivasakannan@eng.monash.edu.my

N. Balasubramanian
AC College of Technology
Anna University, Chennai, T.N., INDIA

ABSTRACT

The presented work is an attempt to produce activated carbon from the pyrolytic char of the scrap tire, using phosphoric acid as the activating agent. Towards this, as a first step, pyrolytic char was prepared from scrap tires covering a temperature range of 400 to 800°C. The yield of the char was found to vary in a narrow range of 33 to 35% for the temperatures exceeding 450C. The resultant pyrolytic char was impregnated with phosphoric acid and activated at 500°C, for duration of activation ranging from 45 to 150 minutes, for impregnation ratios of 1 and 1.5. An impregnation ratio of 1 was found to yield 42%, with a methylene blue number of 184mg/g, while an impregnation ratio of 1.5, yielded 52% with methylene blue number of 139mg/g. The methylene blue number was found to increase with increase in activation time or with decrease in the yield of the activated carbon. The BET surface area was found to increase with increase in the methylene blue number from 302m2/g to 545m2/g. While all the earlier work using chemical activation reports activation temperature around 800°C, in an inert atmosphere, the present process demands only 500°C, in a self generated atmosphere, to produce activated carbon of comparable quality.

Keywords: Pyrolysis, Phosphoric acid Activation, Char, Methylene blue
 

PREDICTION OF LEACHATE FLOW-RATE IN A MSW LANDFILL SITE USING NEURAL NETWORKS METHOD

Shoou-Yuh Chang
DOE Samuel Massie Chair Professor

Yi Wang
Graduate Research Assistant

Civil and Environmental Engineering Department
North Carolina Agricultural and Technical State University
Greensboro, NC 27411, USA

Email: chang@ncat.edu

ABSTRACT

     Landfill leachate may percolate soils and contaminate groundwater and thus becomes harmful to human health and environment. Many research projects have been conducted to control the leachate generation and simulate the leachate flow, such as the water balance method (WBM) and the Flow Investigation of Landfill Leachate (FILL) model. Other than conventional estimation approaches, the quantity of leachate can also be obtained by forecasting. In this paper, an artificial neural networks (ANNs) model was presented for the prediction of the leachate flow rate in a municipal solid waste (MSW) landfill site.
     The model was developed by a number of design steps, which include data collection, model training, model testing and model validating. As a result of model development, this model was designed with an appropriate architecture for good accuracy and fast convergence. The necessary landfill design data needed to calculate the quantity of leachate were obtained from the US EPA’s Hydrologic Evaluation of Landfill Performance (HELP) model, which is a versatile and accepted landfill design and modeling program. Four soil characteristic parameters, which are porosity, field capacity, wilting point and saturated hydraulic conductivity, in addition to the thickness of refuse layer were varied to generate the corresponding leachate flow rates. Using these pairs of data, the ANNs model was “trained” to produce a desired input and output relationship by a back-propagation (BP) algorithm. With the above configurations, the proposed ANNs model was illustrated to be efficient and accurate in the prediction of leachate flow rates with various data sets. Sensitivity analysis among the five variable parameters was also discussed in this paper.

Keywords: Neural network; Model prediction; Leachate generation; Landfill
 

LEACHING STUDIES AND METAL ANALYSIS OF FLY ASH FROM THERMAL POWER PLANT OF INDIA

P.G. Gaikwad
    Research Scholar, Department of Water Resource Development and Management
Email: pravingaikwad71ster@gmail.com

Deepak Khare
Associate Professor, Department of Water Resource Development and Management
Phone: +91-1332-285393 ; Fax: +91-1332-271073; Email: kharefwt@iitr.ernet.in

G.C. Mishra
Emeritus Fellow, Department of Water Resource Development and Management
Indian Institute of Technology Roorkee
Roorkee-247667, INDIA

ABSTRACT

Major by-product of coal fired power plants is fly ash. Apart from dry disposal, most of the power plants in India still follow wet disposal (ash pond) method. The successful management of waste arising from the combustion of low rank coal for electricity generation presents significant engineering and environmental challenge. X-ray diffractometer studies were carried out on fly ash for the identification of minerals whereas morphology was examined with the help of scanning electron microscope. It was found that majority of fly ash particles are spherical in shape. Elemental composition was determined with the help of FE-SEM EDAX analysis. Leaching behavior of fly ash was investigated with the help of open column percolation test. Leachates were analyzed for pH, conductivity, TDS, salinity. It has been found that the conductivity, TDS and salinity decreases with time. Iron and Manganese were analyzed with help of spectrophotometer DR-2800. Maximum observed values for Iron and Manganese were 0.31mg/lit and 0.9 mg/lit respectively. Further it is found that concentration of iron and manganese also decreases with time.

Keywords: Fly ash disposal; leaching; XRD; SEM graph; leachate analysis; metals