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RECYCLING
OF WASTE GLASS IN Nabil M. Al-Akhras*, Ayman N. Ababneh**, Imad A. Al-Qasem*** *College of Engineering, University of Dammam, Dammam, KSA (on sabbatical leave from Jordan University of Science and Technology) **Civil Engineering Department, Jordan University of Science and Technology, Jordan ***Civil Engineering Department, An-Najah National University, Nablus
ABSTRACT
There is a growing environmental concern in many countries around the world from the accumulation of solid waste glass since not all glass can be recycled into new glass. This study explores the recycling of solid waste glass in concrete mixtures to reduce the environmental pollution and to improve the properties of concrete material. Three waste glass powder (WGP) levels were considered in this study: 5%, 10% and 15%. The properties investigated include: setting time, workability, compressive and flexural strength and micro-structure of mortar. The mortar mixtures proportions were 1:3:0.7 by weight for cement, sand and water, respectively. The results showed that the solid waste glass can be recycled in cement concrete mixtures and improve the properties of concrete. The setting time of cement paste increased and the workability decreased with the increase of the WGP content. The compressive strength of mortar increased with the increase of WGP as partial replacement of limestone sand under moist curing. The flexural strength of mortar increased with the increase of WGP as partial replacement of cement or sand under moist curing. The autoclaved WGP mortar showed higher compressive strength and lower flexural strength compared to the moist cured mortar. The scanning electron microscopy images showed that WGP material is good filler because it reduced the porosity of mortar.
Keywords: Autoclaving; Mortar; Mechanical properties; Setting time; Waste Glass powder; Workability
REMOVAL AND RECOVERY OF PENTACHLOROPHENOL ONTO LOW COST NANO POROUS CARBON—KINETICS AND ISOTHERMS
R. Subha, C. Namasivayam* Environmental Chemistry Division, Department of Environmental Sciences Bharathiar University, Coimbatore – 641046 INDIA ABSTRACT
Removal and recovery of pentachlorophenol (PCP) from aqueous solution was investigated using ZnCl2 activated carbon developed from coir pith (ZnCPC), an agricultural solid waste. Variables studied include adsorbate concentration, adsorbent dose, pH and temperature. Langmuir, Freundlich, Dubinin Radushkevich (D-R) and Temkin isotherms were used to model the adsorption equilibrium data and the system followed Langmuir and Freundlich isotherms. Langmuir adsorption capacity of the adsorbent was found to be 189 mg/g. Kinetic studies showed that the adsorption obeyed second order kinetics. Effect of temperature on adsorption was not significant. pH effect and desorption studies showed that ion exchange mechanism might be predominant at pH 10.0 in the adsorption process. Removal of PCP from synthetic wastewater was also tested.
Keywords: Coir pith, ZnCl2 activated carbon, Adsorption, Kinetics, Isotherms, pH effect
CHARACTERIZATION OF AIR-QUENCHING STEEL SLAG AND ITS UTILIZATION AS ADMIXTURE IN PORTLAND CEMENT
Guanghong Sheng1, Yaqin Mou1, Xinrong Wu 2, Liaosha Li2 1School of Architecture and Civil Engineering, Anhui University of Technology Maanshan 243002, CHINA 2Anhui Provincial Key Laboratory for Metallurgical Engineering & Resources Recycling Anhui University of Technology, Maanshan 243002, CHINA ABSTRACT
Steel slag coming from air quenching process is different from slags from other pretreatment processes, such as air cooling process, hot-splashing process, etc. This research investigated the characterization of steel slag producing from the air-quenching process and its utilization in Portland cement. The results showed that the air-quenching steel slag was about <10mm spherical particle and the D50 particle sizes of the investigated samples were only 0.98 mm and 1.22 mm, respectively. Its main mineralogical compositions were calcium silicate (including dicalcium silicate and tricalcium silicate), dicalcium ferrite, merwinite, RO phase and magnetite, while its minor mineralogical composition was periclase. A little free CaO existed in the steel slag but couldn’t be detected by the XRD for its lower content. The study of effects of grinded air-quenching steel slag on the physical performance and hydration process of Portland cement showed that the pozzolanic activity of air-quenching steel slag was lower at early time but increased continually in the future. The air-quenching steel slag wasn’t damaged to the volume stability performance of the Portland cement for its lower free CaO and free MgO content in this research. The hydration products of the steel slag- Portland cement were hydrated calcium silicate, portlandite and ettringite.
Keywords: Air-quenching steel slag; Portland cement; pozzolanic activity; mineralogical composition
CHARACTERIZATION OF INDIAN RED MUD FOR CATALYTIC APPLICATIONS
Snigdha Sushil and Vidya S Batra* Centre for Energy and Environment, TERI University Darbari Seth Block, Habitat Place, Lodhi Road New Delhi 110 003 INDIA ABSTRACT
Red mud (Bauxite waste) collected from different aluminium industries in India was characterized for its potential catalytic properties. X-ray diffraction (XRD), inductively coupled plasma analysis (ICP), BET surface area, scanning electron microscopy (SEM) and temperature-programmed reduction (TPR) were employed for the characterization. In addition, the effect of acid activation and calcination was investigated on the surface area of the solids. Ferric oxide (Fe2O3) was the main component in all samples. The main crystalline phases present were hematite, goethite, gibbsite, boehmite along with other minor forms. Surface area was found to increase after treatments (acid activation and calcination). The highest surface area obtained in activated sample was 172.54 m2/g while in non-activated sample it was 90.06 m2/g corresponding to a calcination temperature of 400 ºC. The increase in surface area due to calcination was observed till a temperature of 400 ºC after which it started declining. Based on the properties, it is proposed that without any major treatment, red mud may be a substitute for the metal oxide catalysts in several reactions.
Keywords: Red mud, aluminium industry, catalyst, characterization, activation
Matthew Franchetti1 and Alexander Spivak The Mechanical, Industrial, and Manufacturing Engineering Department The University of Toledo 2801 W. Bancroft Street Toledo, OH 43606, USA Email: matthew.franchetti@utoledo.edu; alexyn2001@yahoo.com Phone: (419) 530-8051; Fax: (419) 530-8206 Abstract
This paper concentrates on the modeling and optimization of the truck routing collection system for recyclable materials for the Lucas County Solid Waste Management District (the District), located in Northwest Ohio, USA. The purpose of the paper is to describe the process to convert from a multiple-stream recycling process to a single-stream recycling process to reduce operating costs to ensure the sustainability and viability of the system. The newly developed and optimized recycling collection systems contributed to over $100,000 (25%) in annual savings for the District. The District is currently operating a program for collection of recyclable solid wastes from a number of drop-off collection sites throughout Lucas County. The current collection program involves collection of three different streams of recyclables (paper, old corrugated containers and commingled containers). This research considered a proposed optimized single-stream collection system, where all recyclables are initially collected together and separated later at a Material Recovery Facility (MRF). After studying the District’s current collection system three supporting activities were devised: the first activity involved modeling and optimizing the current three-stream collection system. The second activity was to devise, model and optimize a single-stream (commingled) recycling system. The third activity was to demonstrate that the optimized systems resulted in cost savings compared to the current non optimized collection system. The optimized systems were developed in such a way, that both systems are economical and convenient to implement. Then, the optimized systems were compared to determine whether single-stream (commingled) collection is superior to three-stream collection. The following results were obtained when systems were compared: By optimization of the single-stream and three-stream collection, the savings, compared to the current system, would be at least $107,000 per year. By commingling the recyclables into a single collection stream, total annual collection savings, compared to the current system, would be at least $118,000. Keywords: Recycling, single-stream, multi-stream, optimization, modeling
Kolawole J. Osinubi Dept. of Civil Engineering, Ahmadu Bello University Zaria 810001, NIGERIA Email: kosinubi@yahoo.com Adrian O. Eberemu Dept. of Civil Engineering, Ahmadu Bello University Zaria 810001, NIGERIA Email: aeberemu@yahoo.com
ABSTRACT
A reddish brown lateritic soil treated with up to 12% bagasse ash content was compacted using reduced Proctor, standard Proctor, West African Standard or ‘intermediate’ and modified Proctor efforts at moulding water contents -2, 0, 2 and 4% of optimum moisture content. Samples were extruded from the compaction moulds and allowed to air dry in the laboratory in order to assess the effect of desiccation-induced shrinkage on the material for use as a hydraulic barrier in waste containment application. Results recorded show that volumetric shrinkage strain (VSS) values were large within the first 5 days of drying; VSS values increased with higher moulding water content, water content relative to the optimum and bagasse ash content. VSS generally increased with higher initial degree of saturation for all compactive efforts, irrespective of the level of bagasse ash treatment. A compaction plane of acceptable zones for VSS based on the regulatory value ≤ 4% gave an optimal 8% bagasse ash treatment for lateritic soil to be used in waste containment application. Keywords: Acceptable Zones, Compaction, Covers, Lateritic Soil, Liner, Volumetric Shrinkage, Waste Containment, Water Content
Ayodeji Ifegbesan Department of Curriculum Studies & Instructional Technology Faculty of Education Olabisi Onabanjo University Ogun State, NIGERIA Email: ayodeji_ifegbesan@yahoo.co.uk
ABSTRACT
This paper presents the findings of the waste management awareness, knowledge and practices held by a group of secondary school teachers in Ogun State, South-West, Nigeria. Using the theory of planned behaviour as framework, a 34-item researcher designed survey instrument-waste management awareness, knowledge and practice questionnaire (WMKABQ) was administered on 240 teachers selected across the four geo-political zones in the State. The data were analysed using percentage, mean, chi-square, t-test, analysis of variance (ANOVA) and multiple regression analysis. The results show that teachers are aware and knowledgeable about waste management in their schools. However, they possess negative waste management practices. Significant differences were found in teachers’ sex, age, educational qualification, teaching experience, subject of specialisation and their knowledge and practice of waste management. While no significant differences were found in the awareness of waste management of teachers according to sex, class taught, and school location. Sex, age, subject specialisation, class taught, school location and educational qualification were found to be related to teachers waste management practices. Moreover, sex, age, teaching experience, class taught, school location and subject of specialisation were found to be predictors of teachers’ knowledge and practice of waste management. The findings from this study are of relevance to decision makers bringing environmental education into the policy of teacher education institutions, and for programme developers, on effective directions for integrating environmental education given the structures and frameworks of current programmes. Keywords: Environmental awareness, attitude, knowledge, environmental practice, waste management, teacher education
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