Issue 4, November 2016
SUSTAINABLE APPLICATION OF AGRO-INDUSTRIAL BIOMASS WASTE
FOR WATER TREATMENT: RECYCLING OF SUNFLOWER SEEDS
HULLS FOR AMMONIUM REMOVAL
Zainab Z. Ismail*1, Basma B. Hameed2
1Department of Environmental Engineering, Baghdad University, Baghdad, Iraq
2Ministry of Education, Baghdad, Iraq
Water polluted with high concentrations of ammonium ions may pose serious threats to aquatic ecosystems and can eventually lead to eutrophication. The use of agro-industrial waste materials could be a sustainable approach for ammonium ions removal. To address this suggestion, the present study investigates a new application of waste sunflower seeds hulls for ammonium ions removal from aqueous solutions under different experimental conditions. Results revealed that the removal capacity increases with increasing the initial concentration of ammonium ions. Maximum removal efficiency of ammonium ions was 58% achieved within 15 min. At 50 mg/L initial concentration of ammonium ions, sunflower seeds hulls dose of 3 g/L, pH 7, and 1-2 mm particle size, the removal capacity at equilibrium was 9.64 mg/g. Maximum ammonium uptake by sunflower seeds hulls was obtained at a pH range of 6-10. Results indicated that Freundlich model gave more acceptable fit to the experimental data than the Langmuir model with a correlation coefficient of 0.999 suggesting that the sorption conditions are favorable. The experimental data fitted very well the pseudo-second-order kinetic model and also followed by intra-particle diffusion model, whereas diffusion is not only the rate-controlling step. Finally, recycling of sunflower seeds hulls demonstrated a promising option for eutrophic wastewater treatment.
Keywords: Ammonium, Recycling, Sun flower seed hulls, Biosorption, Kinetics, Sustainability
EFFECT OF POLYACRYLAMIDE COATED BIOSOLID ON
PHOSPHORUS MOVEMENT IN A SOIL-PLANT-WATER SYSTEM
Damodhara R. Mailapalli*
Agricultural and Food Engineering Department, Indian Institute of Technology,
Kharagpur, West Bengal, India
Anita M. Thompson
Biological Systems Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
Phone: +91 3222283102
The goal of this research was to understand phosphorus movement in a soil-water-plant system when soil is amended with polyacrylamide (PAM) coated biosolid (BS). Three treatments including no-biosolid (C), commercially available (BS) and PAM coated biosolid (PAM+BS), were applied to manually packed soil columns (bulk density: 1.2 g/cm3). These treatments were studied in a growth chamber with no-crop under no-light condition and in a greenhouse with ryegrass grown under 16-h day light for 60 days. The growth chamber and greenhouse columns were irrigated every week followed by overnight leachate collection. The crop biomass (greenhouse columns) and soil samples were collected bi-weekly and at the end of the experiment, respectively. The samples were analyzed for dissolved reactive phosphorus and total phosphorus. The phosphorous species in the leachate varied significantly and increased after 28 days after incubation for all treatments. For both growth chamber and greenhouse columns, the biosolid treatments (BS or PAM+BS) did not increase phosphorus concentration (or load) in leachate but did enrich phosphorus in the top 1-cm soil depth. Increased application rate with incorporation of biosolid in soil increased ryegrass yield by 3 to 4 times and resulted in more total phosphorus in the soil surface. The total phosphorus lost from the soil column during the experiment was less than 7% of that initially available in the column. The total phosphorus uptake by the ryegrass was 8 to 46 times more than that lost through leachate. The treatment effect on biomass yield and phosphorus load in leachate was not statistically significant, indicating that land application of biosolid (with or without polymer coating) did not increase the potential for phosphorus transport to ground water.
Keywords: Biosolid, polyacrylamide, phosphorus, biomass, ryegrass
ASSESSMENT AND MANAGEMENT OF USED PESTICIDE CONTAINERS FROM FARM LANDS IN KADUNA STATE, NIGERIA
Department of Agronomy,
Ahmadu Bello University, Zaria, Nigeria
Department of Agronomy, Institute for Agricultural Research
Ahmadu Bello University, Zaria, Nigeria
Department of Water Resources & Environmental Engineering,
Ahmadu Bello University, Zaria, Nigeria
College of Agriculture, Division of Agricultural Colleges,
Ahmadu Bello University, Zaria Nigeria
The fast growing demand in agricultural produce and increasing utilization of pesticides on farmlands has introduced management problems of used pesticides containers in Nigeria. This study was carried out to assess disposal and management options for used pesticide containers from farm lands in Kaduna State, Nigeria. The study also quantified the amount of pesticide containers generated in the area and proposed appropriate disposal methods of these pesticide containers in order to promote agricultural development and keep the environment clean and safe. It was also estimated that by the year 2022 the quantity of used pesticides containers used in the state would be up to 9 million containers. The study also revealed problems faced by the farmers and suggested ways by which used pesticide containers can be effectively managed in Nigeria.
Keywords: Pesticide containers, farmlands, disposal, Management, Nigeria
WASTE MANAGEMENT VALUE CHAIN MAPPING AND ANALYSIS IN LOW INCOME NEIGHBORHOODS—NAIROBI, KENYA
Dr. Christine Majale*
Kenyatta University, Box 43844-00100, Nairobi, Kenya
Environmental Consultant, Geoplan Environmental, P.O. Box 11054-00400, Nairobi, Kenya
World Vision- Kenya, Karen Road off Ngong Road, P.O. Box 50816 (00200), Nairobi, Kenya Kevin_mugenya@wvi.org
Waste management value chain analysis is considered to facilitate among other things provision of data necessary in establishing viable types of businesses from waste that can be undertaken to create more employment opportunities hence improving social economic stability. Waste salvaging activities are characteristic of the informal economy linked to the poor and those who cannot find jobs in formal sector. This study looks at waste value chains in two low income neighbourhoods with a population of 81, 288 people in Nairobi-Kenya’s capital city. The study seeks to identify potential market linkages for three waste streams (plastic; paper and organic) value chain and potential barriers for the sector hindering exploitation of the potential it has to be a livelihood opportunity in urban areas. Household questionnaires were administered to a calculated sample of 385 persons, interviews were conducted with relevant key informants and focus groups discussions were held. Findings revealed that there is great potential in the three waste streams with existing and potential market linkages both within and outside the country. There are numerous opportunities and constraints that need to be looked into. The study concludes that with the necessary skills; equipment and support to establish and strengthen existing market linkages, the youths in the area can fully exploit and benefit from waste management.
Keywords: Waste management; Value Chain analysis; Low income; Informal economy
ECONOMICS AND ENVIRONMENTAL IMPACTS OF PLASTIC WASTE RECYCLING: A CASE STUDY OF MUMBAI
Ms. Poonam Vaidya*
Research Scholar CSIR-NEERI-89/B, Dr. Annie Besant Road Worli, Mumbai 400018
Dr. Rakesh Kumar
Director CSIR-NEERI- Nehru Marg, Wardha Road, Vasant Nagar, Nagpur, Maharashtra 440020
Dr. Deepti Sharma
Technical Head, TerraNero Enterprises- 1201, Neha Building, Kores Towers Vartak Nagar,
Thane (W) 400606
The plastic waste (PW) recycling industry in Mumbai was studied to assess the PW stream, recycling activities, economic details of the industry and its impact on the environment. Senior personnel of the local municipality were interviewed for necessary data collection. Also, a total of 179 scrap dealers and recyclers and 35 waste pickers were surveyed within the city limits. A scale was designed to ascertain the environmental impact of PW recycling activities. Results indicate that the PW chain in Mumbai is very complicated, with five alternate routes of reaching the recycler. The PW recycling industry is almost completely informal, with 89.3% of the surveyed units being unlicensed or illegally sub-let. About 700 million tons per day (MTPD) PW is generated, of which almost all is collected for recycling by an estimated 150,000 waste pickers. Environmental impact of 63.2% of the surveyed units was medium. Average cost of pelletizing plastic was INR 22.2/kg (range INR 12-38) while the average selling price was INR 58.6/kg (range INR 35-77). The cost was found to depend upon how soon the PW was extracted from the waste stream. It is strongly recommended that the Mumbai Municipality simplifies the PW stream, at least semi-formalizing the system.
Keywords: Plastic Waste Recycling, Waste Management, Small and Medium Sector, Recycling industry, Mumbai
LEVELS OF POLYCYCLIC AROMATIC HYDROCARBONS
IN WASTE INCINERATION ASH
OF SOME JORDANIAN HOSPITALS USING GC/MS
Dr. Mahmoud A. Alawia *, Nisreen E. Al-Mikhib
Faculty of Science, Department of Chemistry, University of Jordan, Amman-11942, Jordan
Telephone: 00962 777 483679; Fax: 00962 6 5300253
Thirteen PAHs compounds were studied in eleven bottom ash samples of medical waste incinerators from three hospitals in Amman, Irbid and Ma’an/Jordan. The analysis was done using a developed and validated GC/MS method. The detection limits were between 0.049 and 0.582 ng/g. Limits of quantization were between 0.165 and 1.993 ng/g. The instrument precision expressed as coefficient of variation were all <15%. All recoveries were between 76.7 and 98.1%. The results show that the incinerator at Queen Rania hospital in Ma’an produces the highest amount of the carcinogenic benzo(a)pyrene (100 ng TEQ/g) and also the highest total ng TEQ/g (237.23). The least amount of benzo(a)pyrene was produced from Jameel Tutunji hospital in Amman (2 ng TEQ/g) and also the least amount of total ng TEQ/g (14.08ng TEQ/g).
Keywords: PAHs, Toxicity, Bottom ash, Medical waste, Incinerators, Jordan
HOUSEHOLD SOLID WASTE: INFLUENCE OF CITY SIZE AND
ECONOMIC CLASS IN SOUTHERN MINAS GERAIS, BRAZIL
Camila S. Franco1
Adjunct Professor in Engineering Department, Lavras Federal University, Mailbox 3037, CEP 37200-000, Lavras/MG
Luiz F. C. Oliveira
Titular Professor in Lavras Federal University
Antônio M. Silva
Visiting Professor National Sênior in Alfenas Federal University
Adjunct Professor in Lavras Federal University
Sérgio N. Moreira
Bachelor’s degree in State Environmental Foundation
The difficulty in creating a suitable solid waste management by local governments in southern Minas Gerais is due to a lack of information on the situation of quantification and qualification of generation. This study characterized the household solid waste (HSW) in the southern Minas Gerais and related it to the household economic power and size of towns. We performed 385 collections of HSW in 20 statistically selected towns, providing 5% margin of error, covering seven micro-regions, five different city sizes and three household economic classes (A – higher economic level, B and C – lowest economic level). Samples were collected from door to door during the winter and summer. The sampled population generates on average 0.471 and 0.582 kg hab-1 day-1 in the winter and summer, respectively. The largest amounts of HSW were of organic matter (65%) and recyclable or reusable (20%). Medium-sized towns are the largest generators of HSW in the region and larger towns generate more plastic waste thus evidencing their recycling potential. HSW generation is higher in class B households, while generation of recyclables is significantly higher in Class A households. HSW generation does not vary among the seven micro regions, proving that his study is useful for targeting actions to improve HSW management at regional and micro regional levels.
Keywords: Gravimetric analysis. Solid waste management. Shared management
PERSPECTIVE ON THE ROLES AND CHALLENGES
OF WASTE DEALERS IN MALAYSIA
Innocent A. Jereme1, Chamhuri Siwar1, Rawshan Ara Begum2,
Basri Abdul Talib3 , Zaini Sakawi4
1Institute for Environment and Development (LESTARI)
2 Institute of Climate Change, (IPI)
3Faculty of Business and Economics
4Faculties of Social and Humanities
National University of Malaysia (UKM) Science 43600, Bangi Selangor, D, E Malaysia
This paper focused on the roles and activities of waste dealers and the problems facing waste recycling enterprises in Malaysia. Ethnographic methodology such as interview with district officials of waste management, officials from Alam Flora (private waste concessioners) and waste dealers, participant and non participant observation was applied for in-depth understanding of waste recycling activities in Kuala Langat and Sepang districts of Selangor state in Malaysia. The study found that there are formal and informal recycling enterprises who deal on recycling of scrap metals, papers and plastic materials. The study further revealed that problems facing the waste dealers are in two folds such as inconsistent policies on the part of the local councils on mode of business operation for waste dealers and the issue of business registration of their waste enterprise. The findings also revealed that there is so much bureaucracy in registration of waste enterprise with local councils which resulted in many illegal waste operators in these areas. It is of the view of the waste dealers that to reduce illegal disposal of waste in the districts by waste dealers, business registration and operation must be transparent to reduce illegal dumping of both hazardous waste and municipal waste. The implications of this findings is that the challenges of the waste dealers discussed in this study if taken care of could play a crucial role in the government’s effort in achieving 40% recycling target by 2020 in Malaysia.
Keywords: Waste management, Waste dealers, Malaysia and Recycling
Issue 3, August 2016
MODEL OF SECURE LANDFILL USING ABANDONED MINE PIT—TECHNICAL AND ECONOMIC IMPERATIVES IN POOR DEVELOPING NATIONS
M.A. Nwachukwu1* and M.I. Nwachukwu2
1Department of Environmental Science
Federal University of Technology Owerri, Nigeria
2Department of Geosciences
Federal University of Technology Owerri
One growing environmental degradation in poor developing nations is abandoned mine pits. Soon after, these quarries and borrow pits become urban waste dump sites, causing environmental hazards. In most of these countries, including Nigeria, there is no certified sanitary or secure landfill. There is apathy in allocation of fund for waste management and in procurement of land for landfill resulting to poor sanitary conditions. Other challenges facing landfill technology in less advanced society is the cost and availability of suitable bottom liner and other material inputs. To overcome these issues, this paper presents a model design converting abandoned mine pit (AMP) to a secure landfill. Here, clay is used as bottom liner followed by sand/gravel as leachate reservoir, then soil as stabilizer before the waste. This model is affordable, and will achieve the desired security which borders on preventing leachate migration from the wastes to the surrounding environment, particularly groundwater. Other factors supporting this economically secure landfill model are simple design of leachate collection, cheap daily cover, no gas collection and cheap operational cost. Against $20,000,000.00, required for setting up a profit making medium UNEP model landfill, AMP nonprofit landfill model could be set up with about $2,000,000.00. This amount is affordable by governments in most developing nations with or without external aid.
Keyword: Borrow pits, Urban Waste, Landfill Model, Clay liner, Groundwater, Economy, Developing countries
IN-SITU MOISTURE CONTENT MEASUREMENT OF FRESH MUNICIPAL SOLID
WASTE BY WENNER RESISTIVITY METHOD
Sams S. Farhana1, Jebari S. Weekes1, Noureddine Melikechi1, Sahadat Hossain2,
Daniel A. Fluman3, and Mukti M. Rana1 *
Department of Physics & 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, Email: firstname.lastname@example.org
The presence of appropriate moisture content in the Municipal Solid Waste (MSW) is crucial for the decomposition of the refuse. Because of heterogeneous nature of MSW, none of the methods reported for measuring the moisture content of MSW is free of errors. In this paper, the use of the Wenner four-point-probe method to determine the variations of electrical resistivity with moisture content inside the fresh MSW is presented. MSW samples used in this experiment were collected from Sandtown Landfill of Delaware, USA. Six barrels of samples each with a weight of 50 lbs were collected and their physical composition and initial moisture content were determined. The average weight percentage of paper, plastic, food waste, textiles and fabrics, yard waste and wood, metals, glass, styrofoams sponges and other components for all the samples were found to be 36.98%, 23.19%, 14.89%, 5.89%, 1.79%, 3.26%, 3.42%, 1.47% and 8.74% respectively. Experiments were conducted to measure variations in electrical resistivity of MSW with moisture content on weight and volume basis. The average initial moisture content from the fresh MSW was 40.28%. The amount of volatile component present in the samples was also determined with an average value 61.2%. For all samples the resistivity of MSW measured by four point probe method varied inversely with moisture content. The resistivity of the fresh MSW samples at their field moisture contents ranged from approximately 4-60 kOhm-m while the moisture contents varied between 100% to 0%.
Keywords: Municipal Solid Waste, Moisture Content, Wenner Method, Electrical Resistivity
COMBUSTIBLE GASEOUS PRODUCTS FROM PYROLYSIS OF
COMBUSTIBLE FRACTIONS OF MUNICIPAL SOLID WASTE
K. Buah*1, and P. T. Williams2
1University of Mines and Technology, Minerals Engineering Department,
P.O. Box 237, Tarkwa, Ghana
email@example.com; Mobile: 0278898410
2Energy & Resources Research Institute, University of Leeds, Leeds LS2 9JT, UK.
Municipal Solid Waste (MSW) sample was pyrolysed under inert atmosphere of nitrogen in a static bed pyrolysis reactor, heated at a controlled rate of 10 oC min-1 to a final temperature of 700 oC to recover combustible gaseous product. The yield of the combustible gaseous product was 23.01 wt%. Other pyrolysis products were 32.00 wt% char and 44.99 wt% oil. The combustible gaseous product evolved, analysed off line by gas chromatography to contain mainly CO2, CO, H2, CH4, C2H6 and C3H8 has relatively high calorific value of 18.0 MJ m-3, making the gas suitable for use as a fuel. The significance of this research is that the pyrolysis recovered combustible gas can now be stored conveniently and easily transported for various applications. This research, in addition to providing energy needs if implemented, has the capacity to stimulate regular collection of MSW to feed a pyrolysis plant thereby reducing accumulation of the waste in communities, especially in developing countries.
Keywords: Pyrolysis, Combustible Gaseous Products, Municipal Solid Waste
EFFECT OF MECHANICAL REDUCTION OF MORTAR
IN RECYCLED CONCRETE
Viviana Letelier1*, Ester Tarela2, Rodrigo Osses3, Juan Pablo Cárdenas4, Giacomo Moriconi5
1,2,3,4Department of Civil Engineering, Universidad de la Frontera,
Av. Fco. Salazar 01145, Temuco, Chile
5Department of “Scienze e Ingegneria della Materia, dell’Ambiente ed Urbanistica” (SIMAU) Università Politécnica delle Marche, Via Brecce Bianche – 60131 Ancona, Italy
The influence of several parameters on the compressive and flexural strength of concrete with recycled low quality aggregates from precast debris is analyzed. These variables, that affect the mechanical behavior of the concrete, are: recycled aggregates percentage, amount of adhered mortar to the surface of the recycled aggregates, maximum size of the aggregates and amount of cement addition. Mechanical abrasion was used to remove the adhered mortar from the recycled aggregates. Taguchi statistical method was applied considering three levels for each of the four parameters in the analysis, to determine their effects on the compressive strength, obtained after curing the material for 28 and 90 days. Results were quantified through analysis of variance methods (ANOVA). When the abrasion process is applied the amount of adhered mortar is reduced from a 70% to a 58% for 100 rev, and a 44% for 300 rev. The water absorption values confirm these reductions decaying from 3.6% to 3.1% and 2.4% after the RA are subjected to 100 rev y 300 rev respectively. This proves that the mechanical abrasion process is efficient eliminating mortar and improving the quality of the recycled aggregates and of the final material. Restricting the percentage of the recycled aggregates to a maximum of 30% and reducing the adhered mortar allows maintains the compression strengths of the concrete. Eliminating adhered mortar can counterbalance the effect of the cement addition, reducing the cement amount needed to obtain equivalent compression strengths to those of a medium strength control concrete.
Keywords: Recycled aggregates, Compressive strength, Concrete properties, Concrete with recycled aggregates.
ASSESSMENT OF IONIC DIFFUSIVITY IN CEMENTITIOUS
MATERIALS USING ELECTRICAL CONDUCTIVITY
João Marcos M. Vaillant
Federal Center of Technological Education of Minas Gerais – CEFETMG
Av. Amazonas, 7675 – Nova Gameleira – Belo Horizonte – MG
This work aims to present an alternative method to verify the metal ion diffusivity in cementitious materials waste. The method was developed to simplify the calculation of inorganic elements diffusion in porous media. It was based on the electrolytic conduction theory and on Archie’s law. Cylindrical samples of mortars were cast with Portland cement type V, and contaminated with lead and chromium in the proportion of 1000 mg/kg in relation to the cement mass. The leached solution was obtained and assessed from the immersion test, or Tank Test (NEN 7375:2004). The electrical conductivity of the solid sample was measured at each change of the solvent extract, in the saturated condition of dry surface. The results show that the correlations between the equivalent conductivity obtained in the leached solution and in the solid sample enable both an estimate of availability of components to leaching and the coefficient of diffusivity of heavy metals, without chemical analyzes.
Keywords: Leaching, heavy metals, electrical conductivity, ionic diffusion, mortar
PREPARATION OF SILICA FROM CASSAVA PERIDERM
D. Adepojua, J. A. Adebisib*, J. K. Odusoteb, I. I. Ahmedb, S. B. Hassanc
bMaterials and Metallurgical Engineering, University of Ilorin, Ilorin, Nigeria
aMechanical Engineering, University of Ilorin, Ilorin, Nigeria
cMetallurgical and Materials Engineering, University of Lagos, Akoka, Lagos, Nigeria
Cassava peel is a substantial by-product of cassava processing and it constitutes about 13% of the crop. Cassava peel is still currently considered a waste often discarded into the environment indiscriminately, and therefore economically underutilized. In the present work, silica was synthesized from cassava periderm via sol gel route. Cassava periderm was burnt at 600 oC to obtain Cassava Periderm Ash (CPA) prior to alkaline leaching of the silica content which was thereafter precipitated with acid. The silica aquagel was then prepared by pH controlled titration and aging, and followed by drying to form silica. Quantitative analysis showed that silica yield from CPA was 61.53%. The morphology, elemental composition and phases of the silica were investigated with SEM, EDX and XRD respectively. SEM revealed that silica particles are small but not uniform. The EDX compositional analysis confirmed the presence of Si silicon among others present. The Sherrer’s equation used to evaluate the particle size showed that the average particle size of the silica was 62.69 nm. The silica obtained could be used as desiccant in the laboratory, and industrially, as filler for polymer composites and feedstock for production of silicon used in the manufacture of solar panel.
Keywords: Agricultural wastes, Cassava peel, Cassava periderm ash, Sol-Gel, Silica.
INFORMAL ELECTRONIC WASTE RECYCLING IN PAKISTAN
Shakila Umair1,2*, Stefan Anderberg3, José Potting1
1Division of Environmental Strategies Research – fms,
Royal Institute of Technology KTH, SE-100 44, Stockholm, Sweden
2Centre for Sustainable Communications (CESC),
Royal Institute of Technology KTH, SE-100 44, Stockholm, Sweden
3Department of Management and Engineering (IEI),
Linköping Universitet (LiU), Linköping, Sweden
The use of Information and Communication Technologies (ICTs) is growing dramatically all over the world. The fast growth and diffusion of ICTs, their early obsolescence and short life have made electronic waste (e-waste) to the fastest growing waste stream in the world. This waste stream is valuable and highly toxic at the same time, and therefore it requires proper handling. Most e-waste currently ends up in developing countries, like Pakistan, where it is usually recycled informally. Informal recycling involves crude processes, which harm the environment and have severe impacts on the health of recycling workers. This paper analyses the e-waste flows and the informal recycling system in Pakistan, and related governance challenges. Based on field studies in three major cities in Pakistan, we investigate why the e-waste flows keep entering the country, the routes through which they end up in the informal recycling, the actual recycling processes, and identify the various stakeholders and their roles. The analysis illustrates the poor governance that results from weak enforcement of legislation, the complexities emerging with numerous stakeholders, the profitability of informal recycling, little concern for the health damaging exposure for workers from poorest and most vulnerable people in society, and the lack of awareness of the hazards involved. The paper highlights how this business is a market driven entity without priority for proper e-waste handling, which is also hampered by lacking characteristics of good governance, which make it a challenge to control this business.
Keywords: E-waste, Pakistan, import routes, informal recycling system, stakeholder mapping, recycling processes, governance challenges
ACCESSING THE BIOLOGICAL STABILITY OF MUNICIPAL SOLID
WASTE OF DIFFERENT LANDFILLING AGES
Ana Elisa Silva de Abreu, Orencio Monje Vilar
Geotechnical Engineering Department, São Carlos School of Engineering,
University of São Paulo, Av. Trabalhador Sancarlense, 400, 13560-970
São Carlos, SP, Brazil
Municipal solid waste (MSW) degradation in landfills involves many processes and phases that can extend for several years. Accessing the degradation stage of MSW is of paramount importance to many disciplines, since it influences the generation and quality of leachate and gases; landfill settlements and possibly the waste mass stability, amongst other issues. Although there are not current standards to define the boundary between degraded and non-degraded waste, it is common practice to rely on physical, chemical and biological tests on the search for some limiting value which could suggested a stable waste. In this regard, MSW samples with varying ages and buried under different environmental conditions were recovered and tested according to standard procedures for measuring chemical and biochemical oxygen demands; pH; and dissolved organic carbon. Loss on ignition and total organic carbon were evaluated by combustion of solid samples. The tests performed on the eluates correlated well with the tests performed on the solid samples. A unique relationship between time of landfilling and waste degradation could not be observed. Most of the samples showed evidence of an advanced degradation state, but none of them has reached biological stability considered adequate for final storage quality, even though some of them have been buried for more than fifteen years.
Keywords: Municipal solid waste, biodegradation, loss on ignition, BOD5/COD ratio, total organic carbon, final storage quality
Issue 2, May 2016
HYDROGEOCHEMISTRY AND STABLE ISOTOPES OF A SOLID WASTE DISPOSAL
AREA FROM GUALEGUAYCHÚ, ENTRE RÍOS, ARGENTINA
Romina Sanci1*, Héctor Osvaldo Panarello*, Fernanda Cravero+
*Instituto de Geocronología y Geología Isotópica
Universidad Buenos Aires – Consejo Nacional de Investigaciones Científicas y Técnicas, Pabellón INGEIS, Ciudad Universitaria, C1428EHA, Ciudad Autónoma de Buenos Aires, Argentina
+CETMIC (Centro de Tecnología de Recursos Minerales y Cerámica)
Camino Centenario y 506, Gonnet, La Plata, B1897ZCA, Argentina
Tel: +54 1147833021/3022/3023; Fax: +54 1147833024
Major and trace elements, pH, electrical conductivity and organic matter were determined in groundwater and subsoil samples collected from an urban solid waste final disposal site (Gualeguaychú city, Argentina) in order to quantify leachate impact on the quality of these resources. Geochemical modeling results showed mixing process of pristine water and leachate in different proportions which promote, in turn, other processes in the free aquifer such as cation exchange, outgassing of carbon dioxide, precipitation and dissolution of minerals. Anomalous electrical conductivity values of subsoil samples confirmed the leachate impact too. Soil-water interaction allowed the development of natural attenuation processes in water: low dissolved organic carbon (DOC), iron and aluminum concentrations were associated with high amounts in subsoil. High clay content (smectites) and high cation exchange capacity, organic matter and metals analysis suggesting that the exchange and or sorption process were effective. δ13C-DOC constant values ratified the DOC sorption in sediments rather than oxidation. Other natural processes such evaporation and marine ingressions were detected through geochemical models. δ18O y δ2H values suggested not only a meteoric origin for the groundwater but also evaporation and mix process of waters. δ13C-DIC demonstrated that CO2 outgassing could have happened during the mixing.
Keywords: leachate; contamination; environmental isotopes; geochemical processes
WASTE-TO-ENERGY CHARACTERIZATION AND MODELING: A CASE STUDY AT
THE US NAVAL ACADEMY
P.A. Caton*, J. Schmidt, C. Adsit, E. Bermudez, C. Chase, T. Kerner
Department of Mechanical Engineering, US Naval Academy
590 Holloway Road
Annapolis, MD 21402
This study focused on the potential for energy recovery of the low-food waste stream via gasification on a college campus. Waste was sampled using standard sampling protocols from several locations in both academic and residential buildings. Each sample was analyzed qualitatively (categorically) and quantitatively (proximate/ultimate analysis). Relative to average US domestic municipal solid waste (MSW), these waste samples contained higher levels of paper and plastic, comparable food waste, and lower levels of other components. Overall, the waste had lower moisture content and higher energy content than average domestic US MSW. Fuel lean combustion was simulated with excess air and suggested campus waste would produce higher reactor temperatures than average, domestic MSW. The potential for gasification to a producer gas was simulated using a chemical equilibrium approach. Cold gas efficiencies of 85% followed by electric power generation with typical efficiency would result in the potential offset of 2.5% of institutional electricity use, but a combined heat and power approach could also offset a substantial amount of the thermal energy requirements of the institution. A simplified three-component surrogate waste sample was proposed; analysis of two candidate mixtures showed overall good representation of actual campus waste and can facilitate future experimental efforts.
Keywords: Waste characterization, gasification, waste-to-energy, college campus waste, chemical equilibrium, combined-heat-and-power
COMPOSTING OF RUMEN CONTENT WASTE USING
ANAEROBIC-ANOXIC-OXIC (A2/O) SYSTEM
Rhenny Ratnawati*1,3, Yulinah Trihadiningrum1, Sri Rachmania Juliastuti2
1Department of Environmental Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
2Department of Chemical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
3Department of Environmental Engineering, Universitas PGRI Adi Buana, Surabaya, Indonesia
Rumen content waste is generally dried and dumped into municipal landfill by the slaughterhouse (SH) in Indonesia. A composting process using anaerobic-anoxic-oxic (A2/O) method was selected for treating the SH solid waste for its advantage in nitrogen removal. The objectives of this study were to investigate optimum each composting duration, and effect of dolomite addition for alkalinity control. Six standing reactors of 60 L capacity were used in this experiment. Fifty kg of rumen content was placed in each reactor. The A2/O configuration periods of 25-10-15, 15-10-25, and 30-10-10 days were applied in this research. The composting process was conducted for 50 days. Aerobic condition was maintained using aeration rate of 0.5 L (kg-1 dry weight solid waste) min-1. Anoxic condition was established by 60 minute aeration rate of 0.28 L (kg-1 dry weight solid waste) min-1. The composting process was conducted for 50 days. This research showed that the optimum anaerobic-anoxic-oxic time period for composting the rumen content waste was 25-10-15 days. In this reactor, the moisture content was decreased from 83% to 72%. Temperature range was 29-34°C, pH values slightly fluctuated from 7.57 to 8.70. Inorganic nitrogen concentration decreased from 0.29 to 0.07%, and organic nitrogen concentration decreased from 2.04 to 1.19%. Dolomite addition did not give (Pvalue>α, α = 0.05). This research proved that A2O method is appropriate for treating solid waste with high nutrient contents.
Keywords: Anaerobic-anoxic-oxic, composting, rumen content waste
OPPORTUNITY OF BIOCHEMICAL PROCESS FOR PHOSPHOGYPSUM UTILIZATION
Ye Chernish, Ph.D.
L Plyatsuk, DSc., Professor
Department of Applied Ecology, Faculty of Technical Systems and Energy Efficient Technologies
Sumy State University, Sumy, 40007, Ukraine
This paper focuses on the study of the phosphogypsum (PG) bioconversion process to elementary sulfur with using the bio-desulphurization system. Objectives of this work regards: production microbially generation (MG) gas under bio-sulfidogenic conditions; the immobilization of Thiobacillus sp. on different support mediums (lavsan fiber and granular activated carbon (GAC)) and the effect of contact time and culture pH on H2S removal. Anaerobic microbiological degradation (AMD) of sewage sludge with phosphogypsum containing sulfur containing substances produces hydrogen sulfide in microbially generation gas. The optimal loading dose of sewage sludge (SS) and dose of phosphogypsum were determined. The system of sulfide bioconversion consisted of the scrubber connected to bio-desulfurization unit. The enrichment culture of T. intermedius and T. ferrooxidans were used in bio-desulphurization system. The optimum operating parameters of desulfurization unit were determined. The usage of lavsan fibre provides maximum H2S removal (89.78% w/w) and maximum bacterial growth reached (3.5·1010 CFU/g) that proves to be more effective than that usage of granular activated carbon. Therefore, pH and contact time were found to be a critical factors in the operation of the H2S bioconversion system of sulfide with using different support mediums. The modification of bio-desulfurization system was carried out using acidophilic mode.
Keywords: Anaerobic microbiological degradation, phosphogypsum, desulphurization, elemental sulfur
EVALUATION AND QUANTIFICATION OF HOUSEHOLD WASTES SENT FOR
RECYCLING THROUGH A SELECTIVE WASTE COLLECTION SYSTEM
Vanessa A. Mantovania, Sandro D. Mancinia *, Thalita R. Barrosa, José L. Ferrazb
aUNESP – Univ. Estadual Paulista, Campus Experimental de Sorocaba
bFaculdade de Tecnologia de Sorocaba
Av. Três de Março, 511 – Alto da Boa Vista. CEP: 18087-180
Sorocaba, SP, Brazil
Tel.: + 55 15 3238 3409; Fax: + 55 15 3228 2842
Studies on solid waste production and composition can provide information to underpin the implementation and/or expansion of selective waste collection systems. This paper presents data about household solid wastes disposed of in the municipal sanitary landfill and collected by the municipal selective waste collection system of Sorocaba, state of São Paulo, Brazil, which was established in 2007. Discards of household solid wastes in the municipality were found to average 612 g/person/day and the population that participates in the selective waste collection program has the potential to ensure that 30% of its household solid wastes do not end up in the landfill. However, this represents only 2.6% of total household solid wastes generated in the municipality. Excluding rejects (6.5 wt.% of the total selectively collected wastes), a total daily amount of recyclable or reusable household wastes of 11 tons and 301 m3 is separated, with paper and plastics standing out as the most frequent items (about 53 wt.% and 79 vol.%). If this waste collection system and its current productivity were maintained and all possible household wastes generated in the city sent for recycling, today’s infrastructure (space, trucks and workers) would have to increase approximately 11-fold.
Keywords: Household wastes; selective waste collection; composition; waste generation per capita; paper; plastics
IMPERIAL SMELTING FURNACE SLAG AS FINE AGGREGATE
IN CEMENT CONCRETE MIXES
Dr. S.B Patil* Dr. A.K. Vyas** Dr. A.B. Gupta** Rashmi S. Patil***
Professor, Department of Civil Engineering
*Dr. Babasaheb Ambedkar Technological University, Lonere – 402 103 INDIA
**Malaviya National Institute of Technology, Jaipur – 302 017 INDIA
*** M.Tech student PDA college of Engineering Gulbarga INDIA
Imperial smelting furnace (ISF) slag a waste byproduct from pyrometullurgical process of Zinc production has been utilized as fine aggregate in Cement concrete mixes. Experiments on the utilization of an industrial waste in Cement concrete mixes were carried out as particle size distribution of the slag is very close to that of fine aggregate used for Cement concrete mixes. Use of an industrial waste in cement concrete mixes of grades M25 and M30 was made for replacing fine aggregate by ISF slag in the range of 0% to 100%. The Engineering 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 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: Byproduct, Concrete, Slag, Zinc, Environmental
USE OF RECYCLED AGGREGATE CONCRETE
IN PAVEMENT CONSTRUCTION
1Faculty member of Department of Civil Engineering
American University of Sharjah, University City, Sharjah, UAE
2Professor of Civil and Environmental Engineering at Michigan State University
Phone: +971 505713765
Field performance of recycled aggregate concrete (RAC) in pavement construction subjected to heavy traffic loads under aggressive weathering conditions was investigated. Test results of laboratory-cured specimens and cores drilled from pavement sections after 270 days of concrete age showed that the RAC mixes can show performance at par or even better than that of corresponding control (normal) concrete mixes. Later-age enhanced strength and durability attributes of RAC concrete suggest its suitability for use in concrete-based infrastructure such as pavement construction. The effect of the quality of parent concrete from which recycled aggregate has been obtained was observed to be significant on the performance of the resulting RAC mix.
Use of RAC in pavement-concrete is estimated to result in major energy and environmental gains besides being a step forward in the direction of sustainable concrete construction. Large scale use of recycled aggregate in concrete pavement construction can significantly economize its construction.
A MULTI-CRITERIA EVALUATION OF THE METHODS FOR
RECYCLING SCRAP TIRES
Shoou-Yuh Chang1, Frank Gronwald2
1DOE Samuel Massie Chair Professor, Dept. of Civil Engineering
North Carolina A&T State Univ., Greensboro, NC 27411
2Research Assistant, Dept. of Civil Engineering
North Carolina A&T State Univ., Greensboro, NC 27411
Worn out tires create numerous problems in the field of solid waste management. The tires are very bulky and take up a lot of premium space in the landfills. Insects and rodents like to use them as homes where they can spread diseases and if the tires catch fire they will emit toxic gasses. There are several methods of disposing of these tires, but no universal method which is considered the best for all situations. This study looks at each method of tire disposal on the basis of cost/benefit analysis, environmental impact, and feasibility. It will be beneficial to all if the best methods were known, and some methods were eliminated to reduce confusion. Four different methods of Multi-Criteria Decision Analysis were performed to determine the optimal solution through a weighted scoring system which accounts for criteria in cost/benefit analysis, environmental impact, and energy production. The study found that retreading tires for reuse was the best option. However, since that is not always a practical or long-term solution the study found that either using the scrap tires to create crumb rubber or for the purpose of civil engineering applications would be the optimal solutions.
Keywords: Tire recycling, multi-criteria decision analysis, tire derived fuel, pyrolysis
ASSESSMENT ON NON-LINEAR MODELS FOR DEMONSTRATING HEAVY
METALS RELEASE BEHAVIOR FROM SOLID WASTE BLOCK
M. Aminul Haque1 2 * , M. A. Hoque1
1Department of Civil and Environmental Engineering
Shahjalal University of Science and Technology, Sylhet, Bangladesh
2Department of Civil Engineering, Leading University, Sylhet, Bangladesh
To reduce the solid waste load and minimize the contaminant like heavy metals migration to the surrounding environment at landfill sites, solid waste was incorporated in paving mortar block by following the solidification/stabilization treatment technique. Two well established non-linear methods such as diffusion equation derived for a plane source model and empirical method employing a polynomial equation were used for the better understanding of the heavy metals like Fe, Cu and Ni migration phenomena. Experimental data representing the releasing heavy metal from paving block were used for non-linear models for calibration. The accuracy of the models was statistically evaluated followed by models parameter estimation. The study showed that polynomial equation is better than diffusion equation for explaining experimental observation. Moreover, in this current study, polynomial equation was extended further three different longer terms namely Model 1, Model 2 and Model 3 respectively using the least squares procedure for examining the best fit profile with the observations. All the three extended models were justified against statistical point of view. Calibration results shows that the polynomial equation with 2.5 degree (Model 2) explains better leaching behavior of Fe and Cu, whereas the Model 3 having third degree polynomial equation is found to be perfect for representing Ni release pattern from the solid waste block. Apart from the calibration approach, the accuracy of Model 2 and Model 3 were validated with respective experimental observation followed by the model parameters estimation with 95% confidence interval.
Keywords: Solid waste block, Cumulative fraction leached, Model calibration, Parameter estimation
Issue 1, February 2016
EVALUATION OF GROWTH PERFORMANCE OF BIODIESEL
PLANT JATROPHA CURCUS IN FLY ASH—
A WASTE FOR SUSTAINABLE DEVELOPMENT
Seema Raj1, Sumedha Mohan2
1, 2Amity Institute of Biotechnology, Amity University, Noida, U.P., INDIA
1Postal address: Seema Raj, w/o Mr Vishal Raj, AGM- DLF city club,
Phase- 4, Opposite Galaria Market, Gurgaon, Haryana, Pin code: 122002, INDIA
Utilization of waste is a new venture for environmental protection in today’s scenario. Fly ash is an inevitable waste from coal thermal power plants. The management of this huge amount of solid waste is a question of the hour. For giving concern to this problem in the present study the pot culture has been performed for the growth of biodiesel plant Jatropha curcus in Fly ash and its different amendments with soil. Five samples of Fly ash and soil have been used; 100% soil (control), 25% fly ash+ 75% soil, 50% fly ash+ 50% soil, 75% fly ash+ 25% soil and 100% fly ash. The growth parameters such as plant height, number of leaves, pigment content, total nitrogen content and protein content have been determined for the plant growth performance of Jatropha curcus in different samples. All growth parameters in Jatropha curcus are best in 25% fly ash+ 75% soil sample which has average plant height 92.7 cm, average number of leaves are 63, average pigment content is 0.95 mg/g, average total nitrogen content is 5.8 mg/g and average protein content is 38.4 mg/g. So the increase in all growth parameters in low dose of fly ash in soil represents the better utilization of waste for growth of biodiesel plant, which gives a way to sustainable development, reduction in the problem of fly ash disposal and absorption of green house gases as carbon dioxide and methane.
Keywords: Fly ash, waste, Jatropha curcus, soil amendments, plant growth
INCENTIVIZING PUBLIC OFFICIALS
ON WASTE REDUCTION AND RECYCLING
Jackson State University, Urban and Regional Planning Program
101 W. Capitol Street
Jackson, MS 39201, USA
Absence of community recycling is partly to blame for Mississippi’s high per capita MSW landfilling. Recycling opportunities are scarce in the state as there are only 50 drop-off and 21 curbside recycling programs for almost 3 million inhabitants. Since community recycling is primarily a local government prerogative, county and municipal officials were invited to attend the United States Department of Agriculture – sponsored free workshops on waste management, recycling and minimization. Post-workshop investigation however detected a weak marketing strategy, narrowcasting and the absence of alternative plans for enhancing participation. In-depth probing suggests that the key to a successful publicity is to use a multi-prong strategy combining workshops, social media and delivering presentations and education materials intermittently to forums frequented by the stakeholders.
Keywords: Solid waste management, waste reduction and recycling, local government officials, public education and awareness
SUSTAINABLE USE OF RECYCLED GLASS
IN PORTLAND CEMENT CONCRETE
Kaveh Afshinnia1, Graduate Research Assistant
Prasada Rao Rangaraju, Ph.D., P.E., Professor
Glenn Department of Civil Engineering
Clemson, SC, 29634-0911
Tel: (864) 650-6997
Even though significant strides have been made in recovering glass waste from Municipal Solid Waste and recycling it to produce new glass, recent statistics released by Environmental Protection Agency as well as several states suggest that a substantial amount of glass is still disposed of in landfills. Employing glass as either an aggregate or cementitious material in Portland cement concrete can not only eliminate waste glass from landfills, but also reduce both the carbon footprint of concrete by minimizing the usage of Portland cement and quarried aggregate. This study evaluates two methods for employing glass as either a cementitious or aggregate material in concrete. A brief comparison has also been made of the energy consumption and carbon dioxide emissions of conventional concrete versus concrete containing glass aggregate or powder. This study concludes that significant amounts of waste glass can be used in concrete if specific dosages of glass powder or other SCMs are added to the mixture. Also, the use of finely ground glass powder along with crushed glass aggregate can completely eliminate potential durability problems such as alkali-silica reaction in concrete induced by the use of crushed glass aggregates alone in the mixture.
Keywords: Concrete, carbon dioxide, energy consumption, glass aggregate, glass powder, Portland cement concrete
ASSESSMENT OF DUNE SAND-BENTONITE MIXTURES
FOR USE AS LANDFILL LINERS
Yahia Mohamedzein, Ahmed Al-Ghaithi, Mohamed Al-Aghbari, Bakhit Tabook
Department of Civil and Architectural Engineering
Sultan Qaboos University
Al-Khod, Sultanate of Oman
This study investigates the potential use of dune sand-bentonite mixtures as landfill liners. Bentonite was added in percentages of 5 to 20%. The suitability of the sand-bentonite mixtures was evaluated in terms of hydraulic conductivity, swelling/shrinkage, compressibility and shear strength. The hydraulic conductivity of the dune sand-bentonite mixtures decreases with the increase in bentonite content in a power form. Beyond 15% of bentonite the rate of decrease is small. Acceptable values of hydraulic conductivity ( < 10-7 cm/sec) were obtained for a bentonite content of 10% and more. The swelling pressure (and swelling percent) increases substantially with the increase in bentonite content specially when the bentonite content increased beyond 15%. The linear shrinkage of the sand-bentonite mixtures increases with the increase in bentonite content. Below 15% of bentonite the swelling and shrinkage potentials are small. The compressibility parameters (i.e. the compression index (cc) the recompression index (cr) and the coefficient of consolidation (cv) are practically constant with the bentonite content and are within the range reported in the literature for clays. The compressibility of sand-bentonite mixtures is generally small. The sand-bentonite mixtures possess both cohesion and angle of internal friction. The shear strength increases with the increase in bentonite content at low normal stresses and independent of bentonite content at higher normal stresses. The results of scanning electron microscope (SEM) were used to explain the mechanisms behind the variation of the above engineering parameters.
Keywords: Bentonite; dune sand; hydraulic conductivity; landfill liners; shear strength; shrinkage, swelling- consolidation
HOUSEHOLD SOLID WASTE GENERATION RATE AND PHYSICAL
COMPOSITION ANALYSIS: CASE OF SEKONDI-TAKORADI
METROPOLIS IN THE WESTERN REGION, GHANA
Eugene Atta Nyankson¹*, Bernard Fei-Baffoe1, and John Gorkeh-Miah2
1Department of Environmental Science, Kwame Nkrumah University of Science and Technology
2Department of Waste Management, Sekondi-Takoradi Metropolitan Assembly
Sekondi-Takoradi Metropolis, one of the rapidly expanding cities of Ghana has been facing serious problems with solid waste management. This is partly due to the lack of available information about the types and quantity of solid waste generation in the area. Hence, the objective of this study was to determine the rate of household solid waste generation and its composition in the aforesaid city. The methodology and procedures for this study were derived from the Standard Test Method for Determination of the Composition of Unprocessed MSW (ASTM D 5231-92). All samples were hand sorted into 6 waste categories (paper, plastic, organics, metals, glass, and other waste). The study revealed that by weight, organic wastes constitutes the largest proportion of household solid waste (38%) followed by 19% plastics, 7% papers, 4% metals, 4% glass and 28% other wastes (comprising of sand, stones, ash, inert substances). The rate of daily waste generation per capita in the low, middle and high income households were 0.27±0.19, 0.4±0.19 and 0.58±0.24 kg/cap/day, respectively. The study revealed that there is no waste treatment or recovery facility established within the metropolis hence no significant waste recovery and reuse activities exist.. The study showed that more than 38 % of the waste generated in Sekondi-Takoradi Metropolis is decomposable organic matter that can be re-used through composting as well as 34% of the waste having recycling potential thereby considerably mitigating the solid waste problem.
Keywords: Municipal solid waste, waste composition, generation, household, recovery
ASSESSMENT OF WILLINGNESS TO PAY FOR IMPROVED SOLID WASTE
MANAGEMENT BY RURAL FARMING HOUSEHOLDS IN KWARA STATE, NIGERIA
O. A. Omotesho, A. Falola*, S. O. Awolu
Department of Agricultural Economics and Farm Management
University of Ilorin
P.M. B 1515, Ilorin, Kwara State, Nigeria
Tel.: +2348032885450, +2348154557502
The need for improved solid waste management (SWM) cannot be overlooked. Hitherto in Nigeria, SWM was generally considered urban-focused and limited attention was paid to the rural areas, which form the larger proportion of the country’s farming households. These days however, many state governments are partnering with private organizations with the goal of achieving improved SWM system. This study therefore examined willingness-to-pay (WTP) for SWM services by farming households in rural areas of Kwara State, Nigeria. Primary data were obtained from 120 rural households. An open-ended elicitation method was used to obtain the WTP and a probit regression model was used to analyze the factors affecting their WTP. The main SWM methods used by the households were land-filling (50.8%) and open-burning (40%). Although all the households were aware of the effects of poor SWM on health and well-being, 80.6% were willing to pay for the services. The average WTP was N696/month (US$ 4.22/month) by a household. The significant determinants of WTP for the services by the households were educational level of the household head (p<0.05), household income (p<0.01) and amount of waste generated per week (p<0.1). The study therefore recommends improving the educational status and income of the rural households and provision of improved SWM services at an affordable rate
Keywords: Solid waste management, Healthy living, Rural households, willingness to pay, Factors
POZZLANIC REACTION OF FEO-SIO2 SLAG WITH PORTLANDITE
Guanghong Sheng*1,2, Bo Wang1, Shisheng Wang1, Zhiyu Wang2
1School of Energy and Environment
Anhui University of Technology
Maanshan, China, 243002
2Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources
Shangluo, China, 726000
Email: firstname.lastname@example.org Tel/Fax: +86-555-2312910
This manuscript was to investigate the pozzolanic activity of FeO-SiO2 slag which contained copper slag and nickel slag. The portlandite content, chemically combined water content, and ions extracted from the hydration product by EDTA after the pozzolanic reaction was investigated. The results indicated that the major mineral of FeO-SiO2 slag was fayalite. FeO-SiO2 slag had a low pozzolanic activity before hydration of 7 days and increased later, while the finer slag had a high pozzolanic activity. The pozzolanic productions of FeO-SiO2 slag were mainly hydrated calcium silicate (C-S-H) and a small amount of Fe(OH)2 gel. During the reaction, the glass phase of the FeO-SiO2 slag dissolved and generated [SiO4]4-, Fe2+ etc. Then it reacted with Ca(OH)2, which generated C-S-H and Fe(OH)2 gel. A few Fe2+ ions entered the structure of C-S-H by replacing Ca2+ with Fe2+. Finally high [SiO4] polymerization decreased the pozzolanic activity of FeO-SiO2 slag.
Keywords: FeO-SiO2 slag; Pozzolanic activity; Chemically combined water
EXPLORING CRITERIA TO LOCATE SOLID WASTE TRANSFER
STATION IN AN URBAN AREA
Arti Jaiswal1, Dr. Alka Bharat2
1Assistant Professor at School of Planning and Architecture, Bhopal
2Professorat MANIT, Bhopal, M.P., India
Face pace of urbanization and continuous increase in population has led to the increase in quantity of municipal solid waste. This has made it more difficult to locate appropriate sites for waste disposal and storage facilities within urban areas. Transfer station is a facility used for temporarily storage of waste when landfill sites are located far from waste generation areas. Unlike landfill site location which is predominantly based on environment and spatial criteria, in sitting waste transfer station many socio-economic and people related criteria needs to be considered. The aim of this study is to determine important criteria and its related indicators which should be considered during selection of appropriate location for waste transfer station sites. It further undertakes to improve the criteria list through expert opinion on selecting appropriate location for waste transfer station facility. Listed criteria would be useful for decision makers in preparing decision support models for locating waste transfer station facility within urban areas. The study is an attempt to list all criteria which covers all important aspects of location including social, economic, political, spatial aspects etc.
Keywords: Waste Transfer Station; Criteria and indicators; Suitable site; Experts opinion