Fly ash (PFA) is a complex material produced after combustion in coal-fired power plants. About half of this fly ash is disposed as solid wastes. A possible alternative to disposal of the fly ash is the synthesis of zeolite. Zeolite Boggsite (Na37Ca74Al185Si775O192 7H2O) was synthesized from fly ash by hydrothermal treatment with NaOH solutions as identified by x-ray diffraction. The zeolite type and degree of crystallization were found to be dependent on the reaction conditions and mineralogy of the raw material, particularly in terms of the relative concentrations of SiO2 and Al2O3.
Thirteen solid waste samples labeled as scales were collected from a storage area of a crude oil production industry and were analysed for radionuclides concentrations. The radium-226 and radium- 228 concentrations were found to be unexpectedly low, i.e. less than 20 Bqkg. However, six samples were found to contain 7 to 2240 Bq/kg 60 Co. Thus, besides naturally occurring radionuclides, there is a possibility to find artificial radionuclides in solid wastes from crude oil production industry.
The use of environmental planning tools for optimum solid waste landfill siting taking into account all environmental implications was carried out by applying Life Cycle Analysis (LCA) to enhance the research information obtained from initial analysis using Geographical Information Systems (GIS). The objective of this study is to identify the most eco-friendly landfill site by conducting a LCA analysis upon 5 potential GIS generated sites which incorporated eleven important criteria related to the social, environmental, and economical factors. The LCA analysis utilized the daily distance covered by collection trucks among the 5 selected landfill sites to generate inventory data on total energy usage for each landfill sites. The planning and selection of the potential sites were facilitated after conducting environmental impact analysis upon the inventory data which showed the least environmental impact.
Research was conducted to determine suitable chemical parameters as indicators of odor from decomposing food wastes. Prepared food scraps were stored in 18 l plastic buckets (2 kg wet weight each) at 20 °C and 8 °C to reproduce high and low temperature conditions. After 1, 3, 7, 10 and 14 days of storage, the odor from the buckets were marked to an intensity scale of 0 (no odor) to 5 (intense) and the corresponding leachate analyzed for volatile fatty acids, ammonia and total organic carbon. A linear relationship between odor intensity and the measured parameter indicates a suitable odor indicator. Odor intensified with longer storage period and warmer surroundings. The study found ammonia and isovaleric acid to be promising odor indicators. For this food waste mixture, offensive odors were emitted if the ammonia and isovaleric acid contents exceeded 360 mg/l and 940 mg/l, respectively.
Qualitative and quantitative analysis of samples require good judgment from the analysts. These two aspects in gamma spectrometric analysis of Proficiency Test and solid radioactive waste samples for the determination of radionuclides are discussed. It is vital to judge and decide what energy peaks belong to which radionuclides prior to the creation of customized radionuclide library for the analysis of specific samples. Corrections due to radionuclide decay and growth, and the half-life assigned to a particular radionuclide in the uranium and thorium series are also discussed. Discussion on judgment to confirm the presence of thorium in food samples based on gamma spectrometry and neutron activation analysis is also provided.
Developing cities like Khulna, the third largest metropolitan city in Bangladesh, have now begun to confess the environmental and public health risks associated with uncontrolled dumping of solid wastes mainly due to the active participation of non-governmental organizations (NGOs) and community-based organizations (CBOs) in municipal solid waste (MSW) management.
The present study was undertaken to determine the bacterial agents present in various clinical solid wastes, general waste and clinical sharp waste. The waste was collected from different wards/units in a healthcare facility in Penang Island, Malaysia. The presence of bacterial agents in clinical and general waste was determined using the conventional bacteria identification methods. Several pathogenic bacteria including opportunistic bacterial agent such as Pseudomonas aeruginosa, Salmonella spp., Klebsiella pneumoniae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes were detected in clinical solid wastes. The presence of specific pathogenic bacterial strains in clinical sharp waste was determined using 16s rDNA analysis. In this study, several nosocomial pathogenic bacteria strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Lysinibacillus sphaericus, Serratia marcescens, and Staphylococcus aureus were detected in clinical sharp waste. The present study suggests that waste generated from healthcare facilities should be sterilized at the point of generation in order to eliminate nosocomial infections from the general waste or either of the clinical wastes.
Oil palm (Elaeis guineensis Jacq.) fronds (OPF) are the most abundant oil palm solid wastes that are generated during oil palm agriculture and harvest. Palm oil and some other palm wastes have been reported to contain high concentrations of carotenoids with vital bioactive properties. However, the extraction and quantification of carotenoids from OPF have not been reported. In this study, ultrasonic-assisted extraction, HPLC-FLD for quantification, and response surface methodology (RSM) for optimization of β-carotene, lutein, and zeaxanthin from OPF extracts were investigated. The effects of extraction temperature (X1: 30-70°C), extraction time (X2: 10-50 min), and solvent-sample ratio (X3: 10-50 mL/g) on the recovery of β-carotene (Y1), lutein (Y2), and zeaxanthin (Y3) were investigated using three-level Box-Behnken design (BBD) experiment. At a desirability of 1, the optimum extraction conditions for β-carotene (30.14°C, 37.11 min, and 23.18 mL/g), lutein (30.00°C, 39.09 min, and 19.24 mL/g), and zeaxanthin (30.09°C, 36.76 min, and 22.38 mL/g) yielded carotenoid concentrations of 17.95 μg/g dry weight (DW), 261.99 μg/g DW, and 29.99 μg/g DW, respectively.
In this investigation, palm empty fruit bunch (EFB) and almond shell (AS) were implemented as two natural catalysts rich in alkali metals, especially potassium, to enhance the reactivity of tire-char through co-gasification process. Co-gasification experiments were conducted at several blending ratios using isothermal Thermogravimetric analysis (TGA) under CO2. The pronounced effect of inherent alkali content of biomass-chars on promoting the reactivity of tire-char was proven when acid-treated biomass-chars did not exert any catalytic effect on improving the reactivity of tire-char in co-gasification experiments. In kinetic studies of the co-gasified samples in chemically-controlled regime, modified random pore model (M-RPM) was adopted to describe the reactive behavior of the tire-char/biomass-char blends. By virtue of the catalytic effect of biomass, the activation energy for tire-char gasification was lowered from 250 kJ/mol in pure form 203 to 187 kJ/mol for AS-char and EFB-char co-gasified samples, respectively.
Two types of municipal solid waste (MSW), newly arrived and 2 weeks old, were sampled from a sanitary landfill in Pulau Pinang, Malaysia at a fortnightly interval and kept under field conditions for 2 weeks. A total of 480 kg of each type of MSW was sampled to study species composition and impact of delays in cover soil applications on filth fly emergence. Out of 960 kg of MSW sampled, 9.2 ± 0.5 flies emerged per kilogram. Weekly adult fly emergence rates of newly arrived and 2-week-old waste did not differ significantly and MSW remained suitable for fly breeding for up to 1 month. Eight species of flies emerged from the MSW: namely, Musca domestica, Musca sorbens, Synthesiomyia nudiseta, Hydrotaea chalcogaster, Chrysomya megacephala, Lucilia cuprina, Hemipyrellia ligurriens and Sarcophaga sp. Newly arrived waste was determined to be the main source for M. domestica, C. megacephala and L. cuprina in the landfill owing to significantly higher mean emergence compared with 2-week-old waste. Musca sorbens was found in newly arrived waste but not in 2-week-old waste, suggesting that the species was able to survive transportation to landfill but unable to survive landfill conditions. Hemipyrellia ligurriens, H. chalcogaster and S. nudiseta were not imported into the landfill with MSW and pre-existing flies in and around the landfill itself may be their source. The results show that landfills can be a major source of fly breeding if cover soil or temporary cover is not applied daily or on a regular schedule.
Polybrominated diphenyl ethers (PBDEs) are extensively used as flame retardants in many consumer products, and leachates from landfills have been identified as one of the possible sources of PBDEs in the environment. Meanwhile, the unprecedented economic and population growths of some Asian countries over the last decade have led to significant increases in the amount of waste containing PBDEs in that region. This study investigates the status of PBDEs in leachates from municipal solid waste dumping sites (MSWDS) in tropical Asian countries. A total of 46 PBDE congeners were measured, both in the adsorbed (n=24) and dissolved (n=16) phases, in leachate samples collected, from 2002 to 2010, from ten MSWDS distributed among the eight countries of Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, and Malaysia. PBDEs were predominantly found in the adsorbed phase. Partitioning of PBDEs in the dissolved phase was associated with the presence of dissolved organic matter; the apparent organic carbon-normalized partition coefficients (K'oc) of the BDE congeners were lower by two to four orders of magnitude than the K oc predicted from the octanol-water partition coefficients (K ow). The total PBDE concentrations from mono- to deca-BDEs ranged from 3.7 to 133,000 ng/L, and showed a trend toward higher concentrations in the more populous and industrialized Asian countries. The congener profiles in the leachates basically reflected the composition of PBDE technical mixtures. The occurrence of congeners not contained, or in trace concentrations, in technical products (e.g., BDEs 208, 207, 206, 202, 188, 179, 49, 17/25, 8, 1) was observed in most of the leachate samples, suggesting the debromination of technical mixtures, including BDE-209, in the MSWDS of tropical Asian countries. Moreover, the temporal trend indicated the reduction of BDE-209 over time, with a corresponding increase in and/or emergence of lower brominated PBDE congeners. The results indicated that MSWDS of tropical Asian countries are potential sources of environmental PBDEs, which may be transported to the aquatic environment via dissolution with dissolved organic matter. MSWDS could be amplifiers of PBDE toxicity in the environment, possibly through debromination.
As a novel method of purification, an aqueous organic phase system (AOPS) was employed to purify pectinase from mango waste. The effect of different parameters, such as the alcohol concentration (ethanol, 1-propanol, and 2-propanol), the salt type and concentration (ammonium sulfate, potassium phosphate and sodium citrate), the feed stock crude load, the aqueous phase pH and NaCl concentration, were investigated in the recovery of pectinase from mango peel. The partition coefficient (K), selectivity (S), purification factor (PF) and yield (Y, %) were investigated in this study as important parameters for the evaluation of enzyme recovery. The desirable partition efficiency for pectinase purification was achieved in an AOPS of 19% (w/w) ethanol and 22% (w/w) potassium phosphate in the presence of 5% (w/w) NaCl at pH 7.0. Based on the system, the purification factor of pectinase was enhanced 11.7, with a high yield of 97.1%.
Effects of laterite cover soil with different characteristics on survival of buried eggs, third instar larvae, and pupae of Musca domestica (L.) were studied experimentally. Soil treatments were loose dry soil, loose wet soil, compacted dry soil, and compacted wet soil (CWS). Eggs, third instar larvae, and pupae were buried under 30 cm of the different soil treatments and placed under field conditions until adults emerged. Rearing medium was provided for eggs and larvae, and control treatments of all stages were unburied immatures placed on soil surface. Egg and pupal survival to adult were significantly affected by the cover soil treatments, but third instars were more resilient. Wet soil treatments (loose wet soil and CWS) resulted in significantly reduced pupal survival, but increased survival of eggs. However, CWS significantly reduced adult emergence from buried eggs. Though emergence of house flies buried as eggs was significantly reduced, some were able to hatch and emerging first instar larvae developed to pupation. Although cover soil does not completely prevent fly emergence, it did limit development and emergence of buried house flies.
Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA), crude fulvic acids (CFA), crude humin (CH), soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants' diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation.
In this study a GIS model was developed and spatial analytical techniques performed to identify and select a suitable location for a waste transfer station in the sprawling suburban town of Petaling Jaya. The lack of a transfer station in urban centres of Malaysia has caused many problems and affects the efficiency of waste collection and disposal. With diminishing space for landfills and the increasing cost of solid waste management, the need for urban solid-waste recycling has become very important. However, finding a place for waste to be efficiently sorted before unwanted waste can be carried to disposal landfills has social and physical constraints. This study applies GIS techniques and analysis for site selection and identifies an acceptable area. In the model, environmental, physical and social constraints were taken into account, resulting in the selection of a potential area that is acceptable to the residents of the area because it is out of range of causing public nuisance and within minimum travelling distance for collection vehicles. The results show that the potential location for the transfer station should be in proximity of the industrial area of Petaling Jaya, allowing for the possible sale of recyclable materials to local industries. The location is also sited near a major highway to allow quick transportation of the rest of the unwanted waste to the landfill.
Throughout the years, the construction industry has made an important contribution to the Malaysian economy. Moreover, the Ninth Malaysia Plan (2006–2010) has also played a significant role in the demands of executing major residential housing project developments where it has been observed that construction waste was one of the priority waste streams. Due to the increasing number in the population that is actively involved in economic activities, and the modernization of the country, the types of construction waste that are being produced, and identifying the source such as waste are becoming more complex. Therefore, appropriate actions and approaches are needed to be taken with respect to its effective management in handling the solid waste from construction sites. This paper is intended to review the issues and the challenges enclosed within the supply chain management mechanisms in order for improving construction waste management. Throughout this review, useful information and better understanding concerning the current issues, challenges and the supply chain management mechanisms would be made inclusive in the field to be explored. The findings would also assist in improving the quality and awareness on the construction waste management that is being practiced.
Proper implementation of landfill siting with the right regulations and constraints can prevent undesirable long-term effects. Different countries have respective guidelines on criteria for new landfill sites. In this article, we perform a comparative study of municipal solid waste landfill siting criteria stated in the policies and guidelines of eight different constitutional bodies from Malaysia, Australia, India, U.S.A., Europe, China and the Middle East, and the World Bank. Subsequently, a geographic information system (GIS) multi-criteria evaluation model was applied to determine new suitable landfill sites using different criterion parameters using a constraint mapping technique and weighted linear combination. Application of Macro Modeler provided in the GIS-IDRISI Andes software helps in building and executing multi-step models. In addition, the analytic hierarchy process technique was included to determine the criterion weight of the decision maker's preferences as part of the weighted linear combination procedure. The differences in spatial results of suitable sites obtained signifies that dissimilarity in guideline specifications and requirements will have an effect on the decision-making process.
Matched MeSH terms: Solid Waste/analysis; Solid Waste/statistics & numerical data
Biochar has received great attention recently due to its potential to improve soil fertility and immobilize contaminants as well as serving as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochars were produced from empty fruit bunch (EFB) and rice husk (RH) by slow pyrolysis at different temperatures (350, 500, and 650°C) and their physicochemical properties were analysed. The results indicate that porosity, ash content, electrical conductivity (EC), and pH value of both EFB and RH biochars were increased with temperature; however, yield, cation exchange capacity (CEC), and H, C, and N content were decreased with increasing pyrolysis temperature. The Fourier transform IR spectra were similar for both RH and EFB biochars but the functional groups were more distinct in the EFB biochar spectra. There were reductions in the amount of functional groups as pyrolysis temperature increased especially for the EFB biochar. However, total acidity of the functional groups increased with pyrolysis temperature for both biochars.
This paper deals with the solid waste image detection and classification to detect and classify the solid waste bin level. To do so, Hough transform techniques is used for feature extraction to identify the line detection based on image's gradient field. The feedforward neural network (FFNN) model is used to classify the level content of solid waste based on learning concept. Numbers of training have been performed using FFNN to learn and match the targets of the testing images to compute the sum squared error with the performance goal met. The images for each class are used as input samples for classification. Result from the neural network and the rules decision are used to build the receiver operating characteristic (ROC) graph. Decision graph shows the performance of the system waste system based on area under curve (AUC), WS-class reached 0.9875 for excellent result and WS-grade reached 0.8293 for good result. The system has been successfully designated with the motivation of solid waste bin monitoring system that can applied to a wide variety of local municipal authorities system.
In recent years, astaxanthin is claimed to have a 10 times higher antioxidant activity than that of other carotenoids such as lutein, zeaxanthin, canthaxanthin, and β-carotene; the antioxidant activity of astaxanthin is 100 times higher than that of α-tocopherol. Penaeus monodon (tiger shrimp) is the largest commercially available shrimp species and its waste is a rich source of carotenoids such as astaxanthin and its esters. The efficient and environment-friendly recovery of astaxanthins was accomplished by using a supercritical fluid extraction (SFE) technique. The effects of different co-solvents and their concentrations on the yield and composition of the extract were investigated. The following co-solvents were studied prior to the optimization of the SFE technique: ethanol, water, methanol, 50% (v/v) ethanol in water, 50% (v/v) methanol in water, 70% (v/v) ethanol in water, and 70% (v/v) methanol in water. The ethanol extract produced the highest carotenoid yield (84.02 ± 0.8 μg/g) dry weight (DW) with 97.1% recovery. The ethanol extract also produced the highest amount of the extracted astaxanthin complex (58.03 ± 0.1 μg/g DW) and the free astaxanthin content (12.25 ± 0.9 μg/g DW) in the extract. Lutein and β-carotene were the other carotenoids identified. Therefore, ethanol was chosen for further optimization studies.