Issue 4, November, 2014
AN INTEGRATED APPROACH TO ASSESSMENT
OF WASTE-TO-ENERGY OPTIONS
Richard Purser and Dr. Brett Cohen
Energy Research Centre, University of Cape Town
This paper explores the performance of four waste-to-energy (WtE) technologies, incineration, gasification, centralised anaerobic digestion and decentralised anaerobic digestion. It compares a standalone financial analysis of the technologies to one conducted which takes into account the broader waste management programme in which these technologies would be located. Using the City of Cape Town, South Africa, as a case study, incineration was the preferred option in both the standalone and integrated analysis, when using levelised cost of waste as the performance indicator. The ordering of the remaining technologies, however, was different in the standalone and integrated analysis. Furthermore, the ranking of technologies changed when electricity generation and waste diversion potential were used as the performance indicators. These results of the study thus demonstrate that if Waste-to-Energy is to be considered as an option for processing waste and generating electricity, technologies must not be considered in isolation as the results do not present a fair reflection of the financial performance of the technology. In addition, taking on board multiple criteria influences the selection of preferred technology.
Keywords: Waste-to-energy; integrated waste management; thermal technologies; non-thermal technologies, Cape Town
RECYCLE OF PRECIOUS METALS UTILIZING COPPER BASED
INDUSTRIAL PYROMETALLURGY AND ELECTROREFINING
Dr. Corby G. Anderson
Harrison Western Professor
Colorado School of Mines
Mr. Todd S. Fayram
Continental Metallurgical Services
Most applications of copper metallurgy are geared towards primary production. However, as recycling of materials is a growing industry, future facilities could rely on copper metallurgy as a means of processing precious metals. This paper will discuss the derivation of the proposed copper pyrometallurgical and electrometallurgical unit operations to be utilized in industrial recycling of secondary precious metals.
Keywords: Recycle, precious metals, copper, pyrometallurgy, electrorefining
LYSIMETER STUDIES FOR LEACHATE CHARACTERIZATION
GENERATED FROM MUNICIPAL SOLID WASTE
IN PILOT SCALE LANDFILL OF BANGLADESH
Islam M. Rafizul, Yousuf Subbir, Muhammed Alamgir
Department of Civil Engineering, Khulna University of Engineering & Technology (KUET)
This study illustrates the characteristics of leachate generated from municipal solid waste (MSW) deposited in pilot scale landfill lysimeter regarding to the variation of elapsed period and varying operational condition of landfill lysimeter. One lysimeter was simulated as open dump having no top cover and another three lysimeters were considered as sanitary landfill having top cover with different types of soil i.e. sandy loam soil, silty loam soil and clay soil, constructed at KUET campus, Khulna, Bangladesh. Distilled water with an amount equal to 50 % of the daily-recorded rainfall in 2010 was recirculated into each lysimeter once in a week. Moreover, leachate generation rate and amount, leachate characteristics as well as settlement of deposited MSW into each lysimeter at varying lysimeter operational condition were monitored. Result reveals that open dump lysimeter produced more quantity of leachate around 24 % in contrast to the sanitary landfill lysimeter. Moreover, the rate and amount of generated leachate from sanitary lysimeter shows no significant difference among them. The settlement of MSW had been found maximum in open dump lysimeter due to high generation of leachate. Result reveals that lysimeter with sandy loam soil had the lowest concentration and load of most of the pollutants, compared with the lysimeters having silty loam and clay soils as the top cover. Finally, it can be concluded that pollutants were significantly deducted in leachate, with a sandy loam soil used as a top cover in pilot scale landfill lysimeter.
Keywords: Landfill lysimeter, MSW, Leachate quality, Cover soil, Khulna.
COMPRESSIBILITY AND SHEAR STRENGTH OF DUMPED MUNICIPAL SOLID WASTE
B. P. Naveen Research Scholar1
P. V.Sivapullaiah Professor2
T. G. Sitharam Professor3
Department of Civil Engineering
Indian Institute of Science
Improper disposal of solid waste has resulted in the formation of large number of waste dumps around most towns and cities. Improper waste management can lead to serious environmental and health hazard. Also these sites are being used for various infrastructural development around the expanding cites to meet the demand for growing needs. The compressibility and shear strength of the dump sites assume importance in reclamation of waste dumps. The shear strength parameters depend on various factors such as age, composition and moisture content of waste. This paper describes a comprehensive laboratory study performed to investigate the compressibility and shear strength properties of more than10-years-old municipal solid waste (MSW) dump site around Bangalore city in India. Particle sizes analysis has shown that about 75% of waste contained particles are coarser than 4.75 mm and 88% of particles were coarser more than 2.36 mm. Standard Proctor compaction tests yielded a maximum dry density of 9.28kN/m3 at 42.8% optimum moisture content for dumped MSW. Consolidation and shear tests were conducted on samples containing size fraction in the range of 4.75 to 0.15 mm and compacted to Proctor’s maximum dry density at optimum water content. Compression ratio value was found to be 0.105. Based on direct shear tests, the friction angle was found to be 25.6 degrees and cohesion was about 10 kPa. Most dump sites are not directly suitable for civil infrastructure requirements.
Keywords: Compaction, Consolidation, Municipal solid waste, Shear strength
HOUSEHOLDS’ PERCEPTION, ATTITUDES AND EXPECTATIONS ON SOLID WASTE MANAGEMENT IN KAMPALA, UGANDA
J. Ojok1*, M. K. Koech2, M. Tole3, J. Okot-Okumu4
1*Formerly Department of Chemistry, Faculty of Science, Kyambogo University, P.O. Box 1, Kyambogo Kampala, Uganda
2Department of Environmental Education, School of Environmental Studies, Kenyatta
University, P.O. Box 43844, Nairobi, Kenya
Phone: +254 720 796839; Email: email@example.com
3Pwani University, P.O. Box 195, Kilifi 80108, Kenya
Phone: +254 721 737672; Email: firstname.lastname@example.org
4Department of Environmental Management, College of Agriculture and Environmental
Management, Makerere University, P.O. Box 7062, Kampala, Uganda
Phone: +256772 411460; Email: email@example.com
The study assessed household perception, attitude and expectations (PAE) on SWM in Kampala City and how PAE influenced household willingness to pay (WTP) for SWM services. The administrative Divisions of Kampala used in this study were purposively stratified according to parishes. Questionnaires were used as the main means of data collection on PAE. The determinants of WTP were established using the Logistic regression model while Tobit model was used to explain the factors that determine the maximum amount of money households were willing to pay. Contingent Valuation Method (CVM) was used to determine the value households attach to solid waste management services. Most households (59.9%) were not satisfied with solid waste management (SWM) services and perceived it as bad (35.7%) or very bad (22.9%). WTP for solid waste management services were by 48.1% of the households surveyed. Residents were on average WTP Ugandan Shillings 5,382 (USD 2.909) per month. The factors influencing WTP were gender (p<0.001), age (p=0.012), education level (p<0.001), income (p<0.001), marital status (p=0.036), household size (p<0.001) and migration status (p=0.045).
Keywords: Contingent valuation, household waste management, perception, willingness to pay
E-WASTE IN GABORONE, BOTSWANA—ASSESSING THE
GENERATION, HANDLING PRACTICES,
AND STRATEGIES FOR IMPROVEMENT
Mesfin Taye, Wisdom Kanda*, Joakim Krook, Mattias Lindahl
Department of Management and Engineering, Environmental Technology and Management
Linköping University, SE-581 83, Linköping, Sweden
Tel.: +46 (0)13 28 16 96, Fax: +46 13 14 94 03
E-waste includes components with economic and environmental importance, thus the need for their sound end-of-life management. This study provides fundamentals regarding the amounts, flows, and handling practices of e-waste in Gaborone, Botswana. A number of relevant stakeholder organisations were interviewed and an in situ waste composition study was conducted. The concentration of e-waste arriving at the municipal landfill is less than 1 weight percent, corresponding to about 1.9 kg/capita/year, far less compared to the estimated 8 weight percent for European Union countries. However, obsolete electr(on)ics are in urban storages primarily due to a lack of tapping mechanisms. Among several inadequacies of the current handling practices is the absence of an e-waste management framework. Improvement routes discussed include public sensitisation and engagement, capacity building, and future exploitation of potentially suitable end-of-life treatment options including the novel phenomenon of enhanced landfill mining.
Keywords: E-waste, Electrical and electronic equipment, Solid waste management, Resource recovery, Botswana
ANALYSIS OF CO2 EMISSIONS OF THE CEMENT PRODUCTION
Maria Luiza Grillo Renó1*, Ricardo Carrasco Carpio, Felipe Martins Torres
Rogério José da Silva, Mirian de Lourdes Noronha Motta Melo
1Universidade Federal de Itajubá, Av. BPS, 1303, Bairro Pinheirinho, Itajubá – MG
2Instituto Federal de Minas Gerais, Rua Padre Alberico, 440, São Luiz, Formiga – MG
The finite nature of global fossil fuel resources, high prices and most importantly, their damaging effect on the environment underscore the need to develop alternative for industrial systems used in the cement production process. The cement industry is an energy intensive industry and emits high quantity of carbon dioxide, so the use of the alternative fuels and other additives in cement production can help resolve air pollution problems associated with the use of conventional fuels. This paper proposed to analyze two alternative fuels: scrap tires and waste oil. The study focused to develop an environmental performance of these alternative fuels in clinker production based on two Case Studies. As well, emphasis was given for the reduction of CO2 emission when applying slag with clinker to produce cement.
Keywords: Clinker, alternative fuel, environmental performance, CO2 emission, cement production
WHAT DRIVES MUNICIPAL SOLID WASTE POLICY MAKING? AN EMPIRICAL ASSESSMENT OF THE EFFECTIVENESS OF TIPPING FEES AND OTHER FACTORS IN ISRAEL
Itai Trilnick*, Alon Tal**
*Graduate Student, University of California, Berkeley
**Visiting Professor, Stanford University
What factors influence the waste policy of local authorities? While central governments make efforts to promote recycling, the major players in municipal waste management are local authorities. This paper explores the factors influencing waste policies of local authorities in Israel in light of the new landfill tax legislated in 2007. Based on interviews with officials overseeing waste management and other stakeholders, a model of waste policy making in local authorities is proposed. A survey among waste officials of local authorities then evaluates the influence of general and specific factors on associated municipal policies. Cost of landfilling and a new landfill tax, is reported as highly influential on waste policies. Other factors, such as the Mayor’s motivation, managerial capacity in the municipality, and recycling markets are also highly influential. While the cost of landfilling is easily targeted by the central government, the latter factors are seldom addressed.
Keywords: Landfill; tax; recycling; policy; municipal; Israel
Management of Construction and Demolition Waste And Its Use For Road Construction In A South African Municipality
Valentina Zedda*, Cristina Trois, Philip Everitt
Centre for Research in Environmental, Coastal and Hydrological Engineering (CRECHE)
Civil Engineering Programme, School of Engineering, University of KwaZulu-Natal
Howard College Campus, Durban, 4041
The management of Construction and Demolition (C&D) waste material plays a relevant social, economic and ecological role in contemporary world. Due to lack of space in the disposal sites, reuse of potentially recyclable material is vital. Finding alternative usage for waste materials is a challenge for municipalities that want to decrease the volume in landfill sites and also a challenge for scientists who want to reduce the environmental impact of these waste materials by promoting alternative uses. An effort in this direction will help and encourage a new economy in equilibrium with the growing necessity of environmental preservation. Moreover, the natural aggregates that are needed for construction purposes have reached inadequate levels today and the establishment of new quarries is discouraged by administrations.
This paper is specifically focused on the C&D waste stream produced in Durban Metropolitan Area, South Africa, with suggestions for its management and recycling. Origin and quality of this material disposed at the Bisasar Road landfill site were investigated and tested to determine its suitability for road pavement uses. The replacement of natural soils with unconventional waste materials is strongly recommended to minimize the use of open quarries for natural aggregates.
The alternative material studied in this research attains the same mechanical performance as natural aggregates despite having different physical characteristics, demonstrating that C&D waste can replace natural aggregates when specific management procedures are performed to mitigate the intrinsic heterogeneity observed in the material. The results obtained from this study demonstrated good performance of the C&D material as base, sub-base, or subgrade material depending on the road category.
Keywords: Construction and demolition waste, waste management, waste stream, recycling, laboratory road tests
ECONOMIC OPTIMIZATION OF LANDFILL MINING
Jan Stenis and William Hogland1
Department of Biology and Environmental Science
SE-391 82 Kalmar
This paper describes a method of optimizing the production economy when excavating an old landfill in order to both minimize its environmental impact and obtain a profit. The analysis employs the equality principle and the ‘Efficient Use of Resources for Optimal Production Economy’ (EUROPE) model introduced by the first-named author for assigning industrial costs to waste. When using this model, waste has the same economic status as any normal industrial product in line with the inherent meaning of the equality principle. Application of the method to landfill mining then creates novel economic incentives for the improvement of the environment and profitability and the technology used when exploiting older landfills. An introduced key factor enables management to immediately obtain an overall comprehension of the economic, technological and environmental performance of their landfill that continuously can be monitored and evaluated. The results of a Norwegian example imply that impure, and hence unwanted, waste fractions have a certain negative impact on the outcome. This is because of the related internal shadow prices for unwanted wastes and wastes of commercial interest created through use of the equality principle. It is beneficial when landfill mining companies act in accordance with the equality principle to promote sustainable development.
Keywords: Landfill mining, the equality principle, the EUROPE model
Issue 3, August 2014
NON-CONVENTIONAL BIOSTABILISATION TECHNOLOGY
OF MUNICIPAL SOLID WASTE
Riccardo Tuffia, Margherita Canditellia, Nazzareno Faustinia, Giovanni Peschetaa
Ermanno Barnia, Lorenzo Cafieroa,1 , Alice Dall’Arab
aENEA Environmental Technologies Unit, Research Center Casaccia
Via Anguillarese 301 Roma, ITALY
bENEA Materials Technologies Unit, Research Center Faenza
Via Ravegnana 186, 48018 Faenza, ITALY
The aim of this work is to evaluate the effects of a natural enzymatic cocktail (PAV) on the biological stabilization processes of municipal solid waste (MSW) measuring the dynamic respiration index (DRI) and the biochemical methane potential (BMP). In a Southern Italian plant waste was treated mechanically and placed into three different piles: static non-treated, static treated with PAV, aerated, turned and treated with PAV. After sampling, respirometric analyses were carried out in laboratory. Experimental tests show that the treated piles led to significantly better results than the untreated one. This is reflected into better values of heap temperatures and DRI, concluding that an aerobic stability is achieved at the end of the experimental campaign. In particular, the PAV action appears to be more effective under static conditions, as periodic turnings bring about a physical scattering within the pile which in turn prevents temperature homogenisation. Conversely, the data interpretation of BMP is more debatable: the anaerobic test clearly ascertained a neat BMP diminution only for the heap which underwent periodic turnings, not allowing to attribute this anaerobic stability clearly to the effect of PAV.
This study showed that the PAV use is promising for both an effective and economic waste management in landfill or mechanical and biological treatment plants.
Keywords: Biostabilisation, PAV, biometanation, respirometric index, municipal solid waste
INCREASING THE VALUE OF DIMENSION STONE WASTE FOR A
MORE ACHIEVABLE SUSTAINABILITY IN THE MANAGEMENT
OF NON-RENEWABLE RESOURCES
C. Furcas, Ph.D. Student
CINSA, Interdepartmental Center of Environmental Science and Engineering
University of Cagliari, Piazza d’Armi, 09123 Cagliari, ITALY
G. Balletto, Ph.D.
Department of Civil, Environmental and Architectural Engineering
University of Cagliari, Piazza d’Armi, 09123 Cagliari, ITALY
The trend of the dimension stone market has great influence in the economic performance of both industrialized and developing countries. Dimension stones are natural rock materials, such as granite, marble, limestone, sandstone, and slate, quarried for commercial purposes. They are extracted as blocks, slabs, tiles, etc., in order to be sold worldwide. Several industrial sectors depend on the exploitation of natural resources. In the present study, the strict correlation between the construction sector and quarrying activity has been highlighted. The analysis suggests that when building activity increases, there is greater demand for dimension stones. However, the dimension stone industry is prone to produce large amounts of stone waste, which are reckoned to be low-valued and, thus, frequently dumped. This could lead to a number of environmental risks, since it includes critical issues such as the increase of land occupation and the continuous waste of natural materials, which are left out by usual industrial processes.
This work will provide data on the global stone production by taking in consideration the related waste production trend in time. The main objective of the study is to highlight both the economic and environmental risks of an improper management of natural stone waste. On the other hand, the opportunities of re-using quarry waste so as to manufacture value-added by-products will be pointed out, especially with reference to different civil engineering applications.
Keywords: Quarrying; dimension stone; production trends; natural stone waste; re-use
MECHANICAL BEHAVIOR OF BAGASSE FIBER REINFORCED EPOXY
COMPOSITES AT LIQUID NITROGEN TEMPERATURE
Dr. Punyapriya Mishra
Department of Mechanical Engineering
The present experimental investigation deals with the mechanical behavior of bagasse fiber reinforced epoxy composites at cryogenic temperature. Bagasse fibers of 10, 15 and 20 wt % were reinforced with epoxy matrix to prepare composite. These were exposed to liquid Nitrogen temperature. Three point bend tests were carried out at a range of 2mm/min to 500mm/min cross head speed to evaluate the sensitivity of mechanical response during these loading conditions. The mechanical performances of these composites at cryogenic temperature were compared with room temperature property. These composites are found to be loading rate sensitive.
Keywords: Epoxy, liquid nitrogen, bagasse fiber
RECYCLING OF BAG-HOUSE DUST FROM FOUNDRY SAND
B. Dugan, C. Anderson
Center for Resource Recovery and Recycling
Kroll Institute of Extractive Metallurgy
Colorado School of Mines, 1400 Maple St.
Golden, Colorado 80401, USA
Non-metallic foundry waste is generally composed of spent green sand, core sand, and dust collected in the ventilation bag-house systems of the foundry facility. Currently, practices exist for the recovery of sand particles from green sand and core sand at the expense of the other constituents via consumption or degradation. However, new methods are necessary to extract values other than sand from the bag-house dust material. This is important, because the dust of composed of as much as 50wt% non-sand recoverable materials, such as coal and clay. This research evaluates the potential to beneficiate bag-house dust material by way of froth flotation. It was determined that the coal constituent of the dust could be beneficially extracted, but not other useful constituents of the dust by this specific method.
Keywords: froth flotation, green sand, coal, bentonite clay
REVIEW AND EVALUATION OF MUNICIPAL SOLID WASTE MANAGEMENT
PRACTICES IN MALAYSIA
Ogboo Chikere Aja1*, Sunday Dalton Oseghale2, Hussain H. Al-Kayiem1
1Mechanical Engineering Department, Universiti Teknologi PETRONAS
Bandar Seri Iskandar, 31750 Tronoh, Perak, MALAYSIA
2School of Social, Development and Environmental Studies, Universiti Kebangsaan Malaysia
43600 UKM Bangi, MALAYSIA
The review is focused on municipal solid waste (MSW) management practices in Malaysia, waste generation rate, waste composition, and the attitude of the people toward sustainability of waste management practice. Malaysian’s MSW management has mainly been landfill where about 80-95% of collected MSW are disposed. Currently, recycling practice is rated at 5% while composting is rarely practiced. Over 30% of collected MSW in Malaysia are recyclable materials but the current status records 5% recovery. Composting has been given poor attention even when over 45% of the MSW generated are organic and biodegradable materials while incineration is still at the early/testing stage. Malaysian MSW is highly commingled because there is no proper sorting thus the waste has high moisture content. Proper sorting at the waste generation point for recovery of reusable materials, recyclable materials and compostable materials will help improve the municipal waste management practice in Malaysia. This will reduce the waste volume sent to landfills and will extend the designed life of the landfills. Awareness on waste reduction is growing but is publicly low implemented which can be attributed to lack of social consciousness.
Keywords: Municipal solid waste, landfill, recycling, composting, sustainable environment
CELL AND COLUMN FLOTATION STUDIES OF A LOW GRADE
SILICEOUS MINE WASTE LIMESTONE SAMPLE
FOR CEMENT MAKING
Danda Srinivas Rao*, Tadiparthi Venkata Vijaya Kumar, Sripada Subba Rao,
Swarna Prabhakar, Guntamadugu Bhaskar Raju
National Metallurgical Laboratory – Madras Centre
CSIR Madras Complex, Taramani, Chennai – 600 113, INDIA
Beneficiation of a low grade siliceous mine waste limestone sample, from Jayantipuram limestone mine, Andhra Pradesh, India assaying 42.62% CaO and 19.07% SiO2 by flotation was studied. Mineralogical studies by microscope as well as X-Ray Diffraction indicated that the low grade limestone sample consists of calcite as a major valuable mineral and quartz as gangue. Direct flotation experiments were carried out using sodium silicate and sodium oleate as depressant for quartz and collector for calcite respectively. Reverse flotation process was also attempted wherein quartz was floated using cationic collector. The advantages and disadvantages of direct flotation in comparison to reverse flotation on grade and recovery of concentrate were discussed. Based on the optimized process parameters of direct flotation, laboratory scale column flotation experiments were carried out. The results of column flotation studies clearly suggest that a limestone concentrate assaying around 50 percent of CaO with less than 8.0 percent SiO2 suitable for cement manufacture could be achieved. Proper utilization of the waste, solid as well as liquid, generated from the flotation proposes was also discussed.
Keywords: Limestone, quartz, flotation, separation, oleic acid, fatty amine, flotation column
DETERMINATION OF METALS IN LEACHATE BY LASER-INDUCED
Sams S. Farhana1, Poopalasingam Sivakumar1, Jebari S. Weekes1
Noureddine Melikechi1, Sahadat Hossain2, Daniel A. Fluman3, Mukti M. Rana1, *
1Department of Physics and Engineering and Optical Science Center for Applied Research
Delaware State University, 1200 N. DuPont Highway, Dover, DE 19901, USA
2Department of Civil Engineering, The University of Texas at Arlington
416 Yates Street, Arlington, TX 76010, USA
3Delaware Solid Waste Authority, 1128 South Bradford Street
Post Office Box 455, Dover, DE 19903, USA
Phone: (302) 857-6588, Fax: (302) 857-6659
We report on the use of Laser Induced Breakdown Spectroscopy (LIBS) for determining presence of metals in landfill leachate samples from the Delaware Solid Waste Authority’s (DSWA) Sandtown, Delaware landfill. A Q switched Nd:YAG laser along with spectrometer, detector and fiber optics cables were used for analyzing the leachate samples. Presence of each metal in the leachate samples has been uniquely identified from the LIBS emission lines associated with each element. The metals detected in the leachate samples include Al, Ba, Ca, Co, Cr, Fe, Li, Mg, Mn, K, Na, Sr, and Zn. The LIBS results were also compared to results obtained by Inductively Coupled Plasma Mass Spectroscopy (Method SW846 6010C). The results show that LIBS can be an inexpensive and attractive analytical technique for environmental monitoring and analysis.
Keywords: Leachate, LIBS, Leachate quality, Metals in Leachate
COLLECTION AND DISPOSITION OF SOLID WASTE IN THE
METROPOLITAN AREA OF BELO HORIZONTE (BRAZIL)
Camila Moreira Assis*
Raphael Tobias de Vasconcelos Barros
Educadora Ambiental e Sanitarista (UFV)
Doutora pelo PPGSMARH (DESA/UFMG)
The lack of quantitative and qualitative information is a problem for solid waste managers, irrespectively of the size of the city. This study aims to generate information that will help this process, namely information regarding urban cleansing activities that can be useful to authorities to carry out efficient management. On-site visits to facilities and research of local documents were carried out for several towns in the metropolitan region of Belo Horizonte (Brazil) in order to collect data which, grouped together as indicators, could be compared. Tables summarizing this information were created, with data concerning specifically the collection and final disposition of solid waste. For each type of variable (operational and economic), variation ranges were estimated (based on existing literature) as very favorable, favorable, less favorable and unfavorable. Despite reinforcing the usefulness and adequacy of indicators, the inaccuracy of input data and local difficulties arising from training issues can be observed.
Keywords: solid waste management, collection and disposition, assessment, indicators, metropolitan region of Belo Horizonte
STUDIES ON EFFECT OF PLASTIC ON BIODEGRADATION
OF VEGETABLE SOLID MARKET WASTE
THROUGH DETAILED ANALYSIS OF LEACHATE
Anupama Singh1, Debabrata Mukhopadhyay2, Jyoti Prakash Sarkar3 Susmita Dutta3 *
1Department of Earth and Environmental Studies, National Institute of Technology Durgapur
Durgapur 713209, INDIA
2Department of Biotechnology, Bengal College of Engineering and Technology, Durgapur
Durgapur 713212, INDIA
3Department of Chemical Engineering, National Institute of Technology Durgapur
Durgapur 713209, INDIA
Due to rapid increase in urbanization and improvement of lifestyle, plastic has become an integrated part of human lives. Literature survey on the amount of plastic in municipal solid waste in different cities around the world reveals that amount of plastic may be as high as 19%. As plastic is non-biodegradable in nature, it is separated from the biodegradable solid waste before biogas production. However, this incurs cost to the process. Therefore, in the present study, biodegradation of Raw Vegetable Wastes has been studied in presence of plastic with an aim to assess the effect of plastic on the rate of biodegradation and investigate the change of structure of plastic during experimentation. The weight of plastic is varied from 0% to 15%; 40 micron plastic is used for such purpose. Anaerobic bioreactor has been used to facilitate biodegradation process and it was run for fifty six days. Leachate has been collected at a regular interval and analyzed for different physico-chemical parameters like pH, Chemical Oxygen Demand, Biochemical Oxygen Demand, Kjeldahl nitrogen, Total Organic Carbon, etc. Cow-dung seed has also been used to enhance the biodegradation process. Its weight has been varied from 0% to 10%.
Keywords: Raw Vegetable Wastes, Plastic, Anaerobic bioreactor, Leachate, Cow-dung
Issue 2, May 2014
DISSOLUTION KINETICS AND PHASE TRANSFORMATIONS OF
AUTOCLAVED AERATED CONCRETE (AAC) IN ALKALINE AND ACID
MEDIA WITHOUT FURTHER ADDITIVES
A. Hartmann*, G. Pawlas, V. Petrov, J.-C. Buhl
Institut für Mineralogie, Universität Hannover
Callinstr.3, 30167 Hannover
The reaction behaviour of autoclaved aerated concrete (AAC) in alkaline solution (4M and 16M NaOH) as well as diluted citric acid (0.5M and 1M C6H8O7) was investigated without addition of further components to the system. The aims of these experimental studies were to estimate the dissolution kinetics of the mineral phases tobermorite, quartz and calcite from AAC in dependence of solvent concentration and to study the time and concentration ruled precipitation of new crystalline and/or amorphous solids during leaching.
The kinetic experiments were performed for times up to 20 h. A temperature of 453 K was selected for the experiments under alkaline conditions to reach high dissolution rates of quartz. Acid treatment was performed at 333 K according to the rapid dissolution of tobermorite and calcite in acids at low temperature with the aim of formation of Ca2+ containing solutions beside precipitates with low calcium but high silica content. The conversion of AAC was followed by XRD, FTIR and SEM/EDX-analysis for each leaching experiment.
Besides strong dissolution of quartz the whole content of tobermorite was found to remain stable in 4 M NaOH over the investigated reaction period. In contrast tobermorite and quartz were both completely converted into solution in 16 M NaOH. Here a crossover reaction of dissolution of tobermorite and quartz and crystallization of sodium calcium hydrogen silicate NaCaSiO3(OH) could be revealed. The onset of precipitation of this new phase was found to start already after 1 h reaction time.
Strong dissolution of tobermorite and calcite hand in hand with the precipitation of new solid material was detected under acid conditions. High background contributions in the XRD diagrams indicate a mostly amorphous character of these precipitates but some weak reflections also show formation of a few amounts of new solid phases like earlandite beside very weak lines of unknown phases.
Summarizing all the experimental results it can be stated that important information on the most suitable leaching conditions can be withdrawn in consideration of further converting of the solids and solutions in materials recycling process.
Keywords: Dissolution kinetics, hydrothermal behavior of tobermorite, recrystallization process, alkaline leaching, acid treatment, AAC recycling
ASSESSMENT OF METAL RECOVERY EFFICIENCY FOR WASTE
PRINTED CIRCUIT BOARDS IN VIETNAM WITH MEMRECS
AND DIFFERENT END-OF-LIFE SCENARIOS
Hoang Long Le, Eiji Yamasue, Hideyuki Okumura, Keiichi N. Ishihara
Graduate School of Energy Science, Kyoto University
Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501
To overcome the poor yardstick of conventional weight basis only approach in evaluating metal recyclability of scraps containing various metal fractions, Model for Evaluating Metals Recycling Efficiency of Complex Scraps (MEMRECS) has been developed in the previous study. MEMRECS approach describes metal recyclability according to its contribution to environmental impacts and natural resources conservation. Hence it is believed to present metal recycling performance in more justifiable manner. In this study, the end-of-life scenarios for waste printed circuit boards (PCBs) from consumer electronic products in Vietnam are modeled. The metal recovery efficiency corresponding to each scenario is evaluated using MEMRECS. The results demonstrate that MEMRECS is applicable to the end-of-life scenario analysis of metal recovery from metals-bearing products. Regarding the solutions for waste PCBs in Vietnam, the current situation of exporting to informal sectors in China would be the worst way due to the huge loss in both natural resources and environmental benefit. Feeding into an existing primary copper smelter could be a good way but only for PCBs containing high gold content. Exporting to the state-of-the-art end-processing facility would yield the highest efficiency for all types of PCBs, which is in an agreement with the ‘Best-of-2-Worlds’ philosophy.
Keywords: Metal recycling; printed circuit boards (PCBs); recovery efficiency; life cycle assessment (LCA)
ANALYSIS OF THE MINERAL COMPOSITION OF TANNERY SOLID WASTES:
THE CASE OF WET-BLUE CHROME SHAVINGS
S. Tahiri *(1), L. Chabaane (1), M. L. Cervera (2), M. de la Guardia (2)
(1)Laboratory of Water and Environment, Faculty of Sciences of El Jadida
Department of Chemistry, B.P.20, El Jadida (24000), MOROCCO
(2) Department of Analytical Chemistry, Research Building, University of Valencia
50 Dr. Moliner St., 46100 Burjassot, Valencia, SPAIN
Wet-blue chrome shavings constitute generally the major solid waste generated in leather industries. Chemical elements were determined in these industrial residues, by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after microwave assisted digestion under pressure with two mixture solutions (HNO3 and H2O) and (HNO3 and HCl), the use of HNO3/HCl being preferable in order to assure the complete dissolution of Cr and the reduction of matrix effect on the determination of trace and ultratrace elements. The analytical method has been developed and fully validated in order to establish an efficient methodology for routine analysis of this kind of samples. Both methods were compared and results obtained were of the same order. Chemical elements detected in leather chrome shavings can be classified according to their content (mg/Kg) in the following order: Cr > Na > Ca > Fe > Mg > K > Al > V > Ti > Co > Zn > Sr > Tl > Mn > Pb > B > Li. For the rest of elements the contents found were, generally, lower than the limit of detection values.
Keywords: Tannery; Chrome shavings; Microwave-assisted digestion; ICP-OES
BIOCHEMICAL CHANGES AND GROWTH RESPONSES INDUCED BY
CADMIUM IN BEAN SEEDLINGS (PHASEOLUS VULGARIS L.)
Ramin Bahmani1*, Mohammad Reza Bihamta2, Davood Habibi3, Peyman Forozesh3
1*Department of Molecular Biology, Sejong University
98 Kunja-Dong, Kwangjin-Gu, Seoul, REPUBLIC OF KOREA
2College of Agriculture and Natural Resources, University of Tehran, Karaj, IRAN
3Department of Agronomy and Plant Breeding, College of Agriculture and Natural Resources Karaj Branch
Islamic Azad University, Mehrshahr, Karaj, IRAN
Cadmium (Cd) is one of the widespread environmental pollutants which has toxicity effect and its consumption by animals and humans with their diet can lead to serious diseases. The Present study was carried out in order to investigate the effect of Cd stress on the growth, SOD activity, Proline and ABA content in bean seedlings. In this experiment, 25 bean seeds genotypes were germinated and grown in laboratory conditions consisting of solution CdCl2 with concentration of 4mg/lit and distilled water (as a control). The seedlings were harvested after 10days and the germination percentage, root and shoot length, fresh weight, sod activity, proline and ABA content were recorded. Application cadmium caused a significant reduction in germination percentage 9.9%, fresh weight 43.2%, root and shoots elongation 83.9% and 66.3%, respectively as compared with that of control while Cd treated plant showed an increase in Sod activity (20.79%), Proline (20.71%) and ABA (41.57%) content compared to control. Based on our results we concluded that, decrease in seed germination and seedling growth by Cd exposure can be related to this toxicity and oxidative stress. Also, the present results revealed that the increase in sod activity, proline and ABA content causes to prevent the occurrence of oxidative damage under Cd stress.
Keywords: ABA, bean, Cadmium, growth, oxidative stress, Proline, SOD. Abbreviations: ABA- Abscisic acid; ROS- reactive oxygen species; SOD- Superoxide dismutase.
DETERMINATION OF KINETICS FOR CO-COMPOSTING OF
ORGANIC FRACTION OF MUNICIPAL SOLID WASTE
WITH PALM OIL MILL SLUDGE (POMS)
Saleh Ali Tweib1, Rakmi Abd Rahman2 Mohd Sahaid Khalil3
1,2,3Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment
University Kebangsaan Malaysia 43600 UKM Bangi Selangor Darul Ehsan Malaysia
Solid waste generated in Malaysia constitutes of large portion of organic material that can be readily composted. Composting which dispose of the organic material, and at the same time producing usable compost as the end product is thought to be a good option for organic wastes disposal. A reactor is chosen to be utilised in this study since it is economical and is a simpler alternative compared to other existing composting systems. Co-composting of palm oil mill sludge (POMS) and solid waste (SW) can be regarded as an environmental-friendly approach if compared to the current method whereby wastes are disposed in landfills. The compost starter was estimated based on its efficiency. The objectives were to investigate the appropriate 1:2 SWK to POMS mixing ration compost maturity and quality. The potential of the composting process is then found by using the proposed substrate and the possible usages of the compost for agricultural activities. Besides that, the physicochemical changes that occurred during the entire process of composting palm oil mill sludge together with solid waste were also studied. The pH value also decreased along the process and the final pH recorded was 7.28. Percentage of moisture content reduced from 64 to 55.32during the process. The highest temperature achieved was about 34.23°C, and eventually dropped to 20°C in the stages which followed. The model resulted in an experimental exponential equation. It also enable the formulation of another linear equation there from, that eventually give in the value of Kl and K2 (whereby Kl is the process constant and K2 is the process variable of a compo sting system). The model produced has a mathematical expression of y = 87.867 X-0.251 with R-square value of 0.943 , and gave in the value of Kl and K2 81.64 and 1.0301. The results showed that the model is capable of describing the actual status of the kinetics composting
Keywords: Michaelis–Menten Model and Composting Kinetics
TRACKING SOURCE-CONTROLLED, EVOLVING PLUMES
UNDERGOING NATURAL ATTENUATION
IN HETEROGENEOUS AQUIFERS
Paul F. Hudak
Department of Geography and Environmental Science Program
University of North Texas
1155 Union Circle #305279
Denton, Texas 76203-5017, USA
Migration tendencies of source-controlled contaminant plumes were examined in one homogeneous and four heterogeneous simulated aquifers. These tendencies were used to inform monitoring strategies aimed at establishing downgradient fronts of plumes as they migrated through an aquifer, undergoing natural attenuation via dilution, hydrodynamic dispersion, and molecular diffusion. Results suggest that monitoring wells located on transects parallel to regional groundwater flow, passing through the source area and cross-gradient margins of an initial contaminant plume, provide useful information for establishing the evolving front of the plume.
Keywords: Groundwater, monitoring, natural attenuation
BIO-ETHANOL PRODUCTION FROM DIOSCOREA BULBIFERA
TUBER (LOCAL NAME: “ADUEGBE”)–A RENEWABLE
NON-CULTIVATED, NON-FOOD, WASTE MATERIAL IN NIGERIA
R. C. Agu1,2*, J. W. Walker1, B. N. Okolo2, A. N. Moneke2, O. C. Amadi2, C. N. Eze2
1The Scotch Whisky Research Institute, Research North Avenue, Riccarton, EH14 4AP, SCOTLAND
2Department of Microbiology, University of Nigeria, Nsukka, NIGERIA
This study examined the potential of waste materials from the tuber of Dioscorea bulbifera (“Aduegbe”) as a viable alternative and cheap source of renewable raw material for bio-ethanol production. Use of renewable waste materials will reduce competition in the use of human grade raw materials for bio-ethanol production. World population continues to expand rapidly with high levels of poverty. Use of human grade raw materials for bio-ethanol production can limit these resources. “Aduegbe” will not compete as a human food source as it is a waste material and is in abundance. Their conversion into bio-ethanol could provide a more appropriate alternative. Peeled “Aduegbe” and the peel produced alcohol yields of 425 and 251 litres of alcohol per tonne (LA/t) on a dry weight basis (dwb) respectively. Rice and sorghum studied for comparison produced higher alcohol yields at 507LA/t and 452 LA/t respectively while millet and buckwheat produced much lower alcohol yields than “Aduegbe” at 392 LA/t and 294 LA/t respectively. Benefit to be gained from this study is that food materials will be available for humans, whilst waste materials will provide renewable raw materials for bio-ethanol production and will provide a cleaner environment by eliminating their dumping or burning into the environment.
Keywords: Dioscorea bulbifera, “Aduegbe”, sorghum, millet, rice, buckwheat, raw material, bio-ethanol
ENVIRONMENTAL PROPERTIES OF WASTE
AND BY-PRODUCT MATERIALS USED IN CONSTRUCTIONS
Dr. Abdelkader T. Ahmed*
Faculty of Engineering, Aswan University
The use of waste and recycled materials in different construction applications become a widespread approach. In this work, six different solid wastes were introduced as construction materials, namely crumb rubber, sawdust, steel filings, fly ash, silica fume and brick fractions. These waste materials are residuals or by-products generated from some activities and industries. Before these wastes are used as construction materials, their environmental impacts should be thoroughly investigated. They encompass ferrous and nonferrous constituents that, in the presence of water, might be released into the groundwater and soil. The aim of this study was to assess the leaching properties of these waste materials and their effect on the environment. To study the behavior of above mentioned waste materials, an experimental program was adopted to manufacture different cubes of 7 cm length from these wastes. Each cube included mixture of clean sand and gravel, and cement in addition to a specific amount of one of these wastes. The cubes were submerged in water with solid to liquid ratio equal ten. Water samples were collected at different intervals and analyzed chemically. For each sample, beside the pH and temperature, four constituents were measured, namely Na, Cu, Pb and Fe. The results showed that adding waste materials to the concrete cube increased the concentration of some elements such as Cu and Na and decreased Pb and Fe. The results showed also that some of these waste materials may increase a release of some constituents into water more than the allowable values of the drinking water; however, they still were less than the constitutes released from the normal concrete which is used already in the field. Theoretical validation showed that the diffusion process is the best phenomenon which can describe the leaching process of the compacted waste materials.
Keywords: Waste and recycled materials; environmental impacts; leaching tests
POST WAR DEVELOPMENTS IN THE SOLID
WASTE MANAGEMENT SECTOR OF SRI LANKA
Ajantha W. Perera, Ph.D.
Founder, National Program on Recycling of Solid Waste
16, Temple Road, Rattanapitiya, Boralesgamuwa, SRI LANKA
Sri Lanka, a small island in the Indian Ocean is at present engaged in post war development work. After 30 years of war, the priority is given by those in authority for development of Infrastructure. The road building, expansion of airports, harbor development seems the priority work of each dayDuring the war most of the garbage dump sites were around the shanties and the rag picker community lived next to these dump sites. The shanty areas are moved to make way for the new projects.
The land in the capital city is marked to be acquired for putting up housing complexes. Hence garbage and the underprivileged are planned to be shifted to the rural areas. However no proper management for garbage is set in place except for daily collection, disposal and landfilling.
Unlike during the war, the movement of people is far more rapid. The number of people daily traveling to the cities especially the capital city Colombo is far greater and increasing daily.
As the Government and the local authorities are keener on structures and very little attention is given for the sustainable management of garbage, through recycling, composting, bio gas production etc. has lead to collection of upto 1200MT of garbage in the Colombo city per day.
Therefore urgent new work is needed in the area of Solid Waste management, such as: Promotion of composting and home gardening in the main cities and its suburbs to reduce the amount of garbage; Use the Law to fine anyone who dispose garbage in a haphazard way; while creating effective awareness programs to segregate waste as requested by the local authorities.
Waste segregation and recycling by private sector encouraged in the major cities. Eco-churches, Eco -hotels, Eco -institutions promoting composting, bio gas, waste segregation and recycling, reusing and reducing waste in the major cities. Urgent promotion of eco -friendly architecture; Promotion of agrochemical free tea, vegetables and fruits; Provision of job opportunities for the rag picker community and low income community in the recycling sector; Promotion of Recycling by the Private Sector: Opening of a Centers to collect recyclables including E waste. Cottage industries using solid waste promoted among the low income communities, and urban women as a way of income generation. Furthermore, use of cloth bags, and bags made of various eco friendly material promoted among the youth through fashion industries.
The paper would discuss how after the War, the non Governmental organizations, the grass root level organization and individuals work hard to promote sustainable garbage management while the Governmental sector gives its priority for infrastructural development. Case studies will be presented.
Keywords: Sri Lanka, Solid Waste, Recycling, Rag Picker
Issue 1, February 2014
2012 PROJECT RESOURCE RECOVERY, REUSE, RECYCLING
AND CONVERSION (PR4C)
Minhua SU, Dr. Kaimin SHIH*
Department of Civil Engineering, The University of Hong Kong
Hong Kong Special Administration Region (HKSAR), CHINA
This paper examines the efforts to recover waste and divert it from landfill in Hong Kong. There is particular emphasis on plastics, WEEE and glass. Current policy and statistics are presented.
Keywords: MSW, Hong Kong, recovery, reuse, recycling, waste conversion
INTENSIFICATION OF ANAEROBIC MICROBIOLOGICAL
DEGRADATION OF SEWAGE SLUDGE AND GYPSUM
WASTE UNDER BIO-SULFIDOGENIC CONDITIONS
L. Plyatsuk, DSc., Professor
E. Chernish, Ph. D. Student*
Department of Applied Ecology, Faculty of Technical Systems and Energy Efficient Technologies
Sumy State University
Sumy, 40007, UKRAINE
The basic stages of сo-processing of sewage sludge and gypsum waste were studied. Biochemical equations of wastes detoxification on the final stage of AMD under bio-sulfidogenic conditions were developed. After biosulfidogenic treatment organic complexes with heavy metals were destroyed and formed insoluble compounds of metal sulfides. Thus, heavy metals were transformed into the unavailable form for plants. The effects of ozone pretreatment on the biodegradability of sewage sludge were determined. The use of the sludge pre-treatments prior to the anaerobic digestion process led to higher hydrogen sulfide productions and organic matter removal efficiencies in mesophilic conditions. In ozonation, the highest increase of soluble COD (68%) was achieved. In the anaerobic bioreactor, after 20 days digested the elimination of CODt and CODs varied between 78–84% and 83–87%, respectively, within advanced operation of anaerobic bioreactor. The hydrogen sulfide production after ozonation was 1.67 times higher than that without pre-treatment. The sulfate reduction was 94.5% in system was maintained. The qualitative and the quantitative of composition the gas phase were analyzed. The technological applications efficiency of such system was formed.
Keywords: anaerobic microbiological degradation, bio-sulfidogenic conditions, sewage sludge, phosphogypsum, ozonation
MUNICIPAL SOLID WASTE COLLECTION AND MANAGEMENT
STRATEGIES IN AKURE, SOUTH-WESTERN NIGERIA
1 A.J. Oloruntade, 2*P.A. Adeoye, 3F. Alao
1Department of Agricultural Engineering Technology
Rufus Giwa Polytechnic, Owo, Ondo, State NIGERIA
2Department of Agricultural and Bioresources Engineering
Federal University of Technology, Minna, Niger State, NIGERIA
3Department of Agricultural Engineering
Federal University of Technology, Akure, Ondo State, NIGERIA
Municipal Solid Waste Management (MSWM) has become one of the greatest problems facing many urban and semi-urban centres of Nigeria. This study presents the various steps and approaches taken in Akure, Southwestern Nigeria, to combat the menace. Such approaches included creation of special agencies for the collection, recycling and conversion of Municipal Solid Waste (MSW) into useful products. Also, recruitment of Sanitary Inspectors and Volunteer Youth Corps, awareness campaigns and collaboration with other government agencies has improved compliance with sanitary laws, thus helping in effective MSWM and making the city appear neater and the environment is more habitable. The study, therefore, suggested the need for MSWM cost sharing between the government and the people, strengthening of all enabling sanitary laws and adequate budgetary allocation for all concerned agencies, involvement of Private Sector Participation (PSP) and awareness campaigns to sustain the present level of MSWM efforts and increase the tempo to guard against future population increase.
Keywords: environment, management, Sanitary Inspectors, solid waste, waste recycling
SOLID WASTE MANAGEMENT PLANNING
USING MULTI-OBJECTIVE GENETIC ALGORITHM
School of Social and Environmental Development, National Institute of Development Administration118 Seri Thai Road, Klong Chan, Bangkapi, Bangkok 10240 THAILAND
Tel.: +662-727-3128, Fax: +662-377-6464
Solid waste management is a complex issue, involving economic, technical, legislative, and environmental aspects. Decision makers should be assisted in identifying different alternatives and selecting the one best suited for their environments. In this research, a graph-based, multi-objective optimization model is proposed for a distributed waste management environment with multiple sources of wastes, multiple types of materials, local processing, and waste transfer routes, taking into account the net cost of the system and volume to the landfill. The non-dominated sorted genetic algorithm-II (NSGA-II) is employed as the optimization technique. The proposed technique was applied to the context of Saraburi Municipality, Thailand. The results show that the proposed model can generate better solutions than that of the current practice, in particular, lower net cost with less volume of waste to the landfill.
Keywords: Waste management; multi-objective optimization; genetic algorithm
TREATMENT OF LEACHATES BY EVAPORATION IN THE SEMIARID
REGION OF THE BRAZILIAN NORTHEAST
Perboyre Barbosa Alcântara
Civil Engineer. Ph.D., Geotechnical Engineering, Federal University at Pernambuco.
Professor, Federal Institute of Education, Science and Technology at Ceará (IFCE)
Juazeiro do Norte Campus, Department of Environmental Engineering
Armando Borges de Castilhos Júnior1
Sanitary and Environmental Engineer. Ph.D., Urban Solid Waste Management and Treatment, INSA Lyon, France. Associate Professor IV, Department of Sanitary and Environmental Engineering, Federal University at Santa Catarina
Evaporation processes have been studied to provide an alternative solution to traditional wastewater treatment systems, especially in regions where they can be technically and economically viable due to local climate conditions. The general objective of this study is to evaluate the installation and monitoring of a pilot system for treatment of leachates from sanitary landfills using natural evaporation techniques in an evaporation panel with a high surface area. The system was installed in a region with a semiarid climate and the results obtained are compared with the data from monitoring an identical experiment conducted in a subtropical humid climate. The results obtained in Juazeiro do Norte, CE, from October 2010- September 2011, in comparison with data obtained in Florianópolis, SC, from January 2008 – September 2008, indicate an average daily evaporation of leachate that is 3.2 times higher, which confirms the potential for use of solar energy for treatment of leachates in regions of semiarid climate.
Keywords: Landfill, Leachate Treatment, Evaporation
A COMPARISON OF THE QUANTITY AND QUALITY OF LEACHATE
GENERATED BY FIVE COMPOST FEEDSTOCKS EXPOSED TO
Mark A. King1*, George MacDonald2, Mark Hutchinson3, Bill Seekins4
1Maine Department of Environmental Protection, Augusta, Maine, USA
2Maine State Planning Office, Augusta, Maine
3University of Maine Cooperative Extension, Knox-Lincoln County Office, Waldoboro, Maine
4Maine Department of Agriculture, Augusta, Maine
A study of five compost feedstocks that have been proposed for use in composting animal carcasses was conducted in the fall of 2008. The purpose of the study was to compare the moisture retention and loss characteristics for the feedstocks by themselves when exposed to extreme rainfall events. It also included analyzing the leachate for a number of characteristics. The study is a prelude to a similar study that will collect data on leachate quantity and quality for one or more of the feedstocks when used to compost an animal carcass. An impervious collection platform was constructed to collect leachate generated by separate piles of various feedstocks, where each pile was exposed to 30 minutes of simulated rainfall (approximately 416 L total or the equivalent of a 25 year/24 hour rain event). Five compost feedstocks that may be used for animal carcass composting were tested: wood chips, a sawdust/shavings mix, leaf and yard waste, horse bedding, and immature sludge-derived compost. Three replicates of each feedstock (Trials 1-3) were constructed into small piles measuring 3 m3 in volume. Each pile received simulated rainfall twice over a seven-day period (on Day 1 and again on Day 7). Piles were covered by moisture impervious materials between simulated rainfall events. Individual leachate samples (100 ml) were collected at regular intervals during the simulated rainfall periods and were analyzed for: micro nutrients; total phosphorus; nitrate-nitrogen; ammonia-nitrogen; total nitrogen; pH; and conductivity. Total leachate volumes varied widely between the various feedstocks tested. Wood chips averaged the most generated leachate (145 L), whereas the sawdust/shavings mix yielded the least leachate (40 L). Municipal sludge compost and horse bedding recorded the highest levels of nitrate-nitrogen in the collected leachate, whereas horse bedding and municipal leaf and yard waste leachate recorded the highest levels of total phosphorus. However, a review of nutrient uptake capacities of vegetation in a grassed filter area, demonstrate that none of the leachate collected during this study would exceed the ability of a vegetated filter area to utilize both nitrate-nitrogen and phosphorus.
Keywords: Compost, leachate, feedstocks, simulated rainfall, wood chips, sawdust shavings mix, leaf and yard waste, horse bedding, sludge-derived compost, nitrate-nitrogen, and phosphorus.
PROPERTIES OF CONCRETE CONTAINING RECYCLED FINE
AGGREGATE AND FLY ASH
Dept. of Civil Engineering
This paper reports the properties of concrete containing recycled fine aggregate (RFA) and fly ash (FA) obtained from local source in Perth, Western Australia (WA). This study is consisted of two parts. In the first part, the properties of concrete containing 25, 50, 75 and 100% (by wt.) replacement of natural fine aggregate (NFA) with RFA are considered. In the second part, the effect of class F fly ash as partial replacement of cement on the properties of recycled concretes containing 25% and 50% RFA are evaluated. The fly ash is used as 30% and 40% replacement of cement. The properties of concrete evaluated are the compressive strength, indirect tensile strength, flexural strength and water absorption. All properties are measured at 7, 28 and 56 days. The results show that, better compressive, tensile and flexural strength of concrete can be obtained in recycled aggregate concretes containing up to 50% RFA as partial replacement of NFA. However, in the case of recycled aggregate concretes containing 30% and 40% fly ash the compressive strength is increase at 56 days and both compressive strength and tensile strengths are decreased at early ages. The flexural strength is increased in recycled aggregate concrete containing fly ash. It is observed that the water absorption is increased as RFA content increased. It is also observed that the water absorption is decreased significantly in recycled aggregate concretes containing fly ash at 56 days.
Keywords: Recycled fine aggregate, fly ash, compressive strength, tensile strength, flexural strength, water absorption
UTILIZATION OF AN INDUSTRIAL WASTE
IN CEMENT CONCRETE MIXES
Dr. S.B. Patil*, Dr. A.K. Vyas**, Dr. A.B. Gupta**
Professor, Department of Civil Engineering
*Dr. Babasaheb Ambedkar Technological University, Lonere – 402 103, INDIA
**Malaviya National Institute of Technology, Jaipur – 302 017, INDIA
Experiments on the utilization of an industrial waste in cement concrete mixes were carried out by using Imperial smelting furnace (ISF) slag, a waste byproduct from pyrometullurgical process of Zinc production. Particle size distribution of the slag is very close to that of fine aggregate used for Cement concrete mixes. Possibility of its use in mixes of grade M20 was designed replacing fine aggregate by ISF slag in the range of 0% to 100%. Mechanical properties of these mixes were evaluated by Compressive Strength. The chemical composition of ISF slag shows presence of heavy metals and the environmental acceptability of such mixes was determined by Toxicity characteristics leaching procedure (TCLP) test recommended by USEPA. This paper presents the detailed results of Strength and TCLP tests. Experimental investigations show that up to 60% replacement of sand by Imperial smelting furnace (ISF) slag satisfies both strength and environmental acceptability.
Keywords: Strength, Leaching, Concrete, Slag, Heavy metals
APPLICATION RESEARCH OF SLAG GRINDING TECHNOLOGY
AND EQUIPMENT OF EFFICIENT ENERGY-SAVING
Jian Tian1, 2,*, Xiaoyu Zhao1, Sanhai Zeng3, Tao Wei1, Huijuan Gao1, Jindi Wang1, Jin He1
1Wuhan Tianshu Technology Development Co., Ltd., Wuhan, 430070, P.R. CHINA
2School of Materials Science & Engineering, Hubei University, Wuhan, 430062, P.R. CHINA
3School of Civil Engineering and Architecture, Hubei University of Technology, Wuhan, 430068, P.R. CHINA
Combined grinding technology of roller press was an organic combination of roller press and ball mill, which integrated the high-efficiency and energy-saving features of roller press and the wide particle grain size distribution, uniform particle group shape and good particle morphology of fine slag powder produced by ball mill. So fine slag powder produced by combined grinding technology had a higher admixture proportion than that produced by vertical mill or other grinding system. When producing fine slag powder with high specific surface area, the combined grinding was of high capacity and low energy consumption. Cement mixed with fine slag powder produced by combined grinding technology had higher strength in each age compared with that mixed with fine slag powder of the same specific surface area produced by vertical mill. So combined grinding should be the first choice, while the fine slag powder produced by it had a better awareness in market.
Keywords: Combined grinding; roller press; fine slag powder; gelling efficiency