Sampling household waste at source: lessons learnt in Gaborone.

Municipal solid waste (MSW) quantity and composition analysis is fundamental for the planning of municipal waste management services. The purpose of this paper is to report the results and experiences of sampling household waste at the source of generation in Gaborone, Botswana. The average generation rate, in kg capita(-1) day(-1), and percentages of various components of waste in Gaborone were determined using a statistically designed household sampling survey. The survey covered 47 households with different socio-economic characteristics over 21 days with 893 samples obtained. The results showed that the average waste generation rate for Gaborone was 0.33 kg capita(-1) day(-1). Contrary to common belief, the waste generation rate measured as in weight units was found not be directly related to household income. However, the packaging fractions of plastic and paper measured as volume had a direct relationship with household income. Across all income groups, the putrescible waste fraction constituted the highest proportion of the waste stream at approximately 68%. The main general conclusion is on the importance of practical considerations. As much as statistically designed sampling procedures provide a useful means of estimating the quantity and composition of household waste at source of generation, there are some practical issues that should be carefully considered during sampling to improve the accuracy and relevance of the results.     

黄土区沟道泥沙微生物群落变化特征及其影响因素

在黄土高原沟壑区,通过16S rRNA基因片段和ITS高通量测序,研究沟道泥沙中细菌和真菌群落在上-中-下游的变化特征.结果表明：与沟头相比,把口站的细菌群落中拟杆菌门（Bacteroidetes）与厚壁菌门（Firmicutes）的相对丰度分别增加6.6%和10.5%,而变形菌门（Proteobacteria）的相对丰度降低15.1%;真菌群落中担子菌门（Basidiomycota）的相对丰度增加7.7%,而子囊菌门（Ascomycota）降低30.2%;泥沙中黏粒含量与细菌丰富度（Chao1指数）和多样性（Shannon指数）之间显著负相关（P<0.05）,与真菌的丰富度和多样性无显著相关性;细菌和真菌群落多样性和丰富度的空间差异与SOC、Olsen-P的变化有关（P<0.05）.因此,泥沙中颗粒组成物和养分含量可能是影响沟道微生物群落变化的主要因素.     

Elemental analysis of total suspended particulate matter in the ambient air of Baghdad

Samples of atmospheric particulate matter obtained from representative areas of the city of Baghdad were collected on glass fiber filters using a high-volume sampler. Atomic absorption techniques were used to analyze the total suspended particulates (TSP) for the following trace metals; Fe, Cu, Zn, Pb, Mn, Cr, Cd, Co, and Hg. Sulfates were measured by turbidemetric method. Ion-selective electrodes was used for chloride analysis. It is concluded that the major components of TSP in the ambient air of Baghdad consist of mineral dust. Pb and Cd gave high enrichment factor values, which implies enrichment of these two metals from anthropogenic sources. High enrichment factors were also obtained for Zn and Cu. It is also concluded that in this arid area, the black smoke reflectance method is not suitable for measuring total suspended matter gravimetrically.     

Pd/silicalite-1: An highly active catalyst for the oxidative removal of toluene

Catalytic combustion is thought as an efficient and economic pathway to remove volatile organic compounds, and its critical issue is the development of high-performance catalytic materials. In this work, we used the in situ synthesis method to prepare the silicalite-1 (S-1)-supported Pd nanoparticles (NPs). It is found that the as-prepared catalysts displayed a hexagonal prism morphology and a surface area of 390−440 m²/g. The sample (0.28Pd/S-1-H) derived after reduction at 500°C in 10 vol% H₂ showed the best catalytic activity for toluene combustion (T_50% = 180°C and T_90% = 189°C at a space velocity of 40,000 mL/(g·hr), turnover frequency (TOF_Pd) at 160°C = 3.46 × 10⁻³ sec⁻¹, and specific reaction rate at 160°C = 63.8 µmol/(g_Pd·sec)), with the apparent activation energy (41 kJ/mol) obtained over the best-performing 0.28Pd/S-1-H sample being much lower than those (51−70 kJ/mol) obtained over the other samples (0.28Pd/S-1-A derived from calcination at 500°C in air, 0.26Pd/S-1-im derived from the impregnation route, and 0.27Pd/ZSM-5-H prepared after reduction at 500°C in 10 vol% H₂). Furthermore, the 0.28Pd/S-1-H sample possessed good thermal stability and its partial deactivation due to CO₂ or H₂O introduction was reversible, but SO₂ addition resulted in an irreversible deactivation. The possible pathways of toluene oxidation over 0.28Pd/S-1-H was toluene → p-methylbenzoquinone → maleic anhydride, benzoic acid, benzaldehyde → carbon dioxide and water. We conclude that the good dispersion of Pd NPs, high adsorption oxygen species concentration, large toluene adsorption capacity, strong acidity, and more Pd⁰ species were responsible for the good catalytic performance of 0.28Pd/S-1-H.     

Determining heavy metals in spent compact fluorescent lamps (CFLs) and their waste management challenges: Some strategies for improving current conditions

From environmental viewpoint, the most important advantage of compact fluorescent lamps (CFLs) is reduction of green house gas emissions. But their significant disadvantage is disposal of spent lamps because of containing a few milligrams of toxic metals, especially mercury and lead. For a successful implementation of any waste management plan, availability of sufficient and accurate information on quantities and compositions of the generated waste and current management conditions is a fundamental prerequisite. In this study, CFLs were selected among 20 different brands in Iran. Content of heavy metals including mercury, lead, nickel, arsenic and chromium was determined by inductive coupled plasma (ICP). Two cities, Tehran and Tabriz, were selected for assessing the current waste management condition of CFLs. The study found that waste generation amount of CFLs in the country was about 159.80, 183.82 and 153.75 million per year in 2010, 2011 and 2012, respectively. Waste generation rate of CFLs in Iran was determined to be 2.05 per person in 2012. The average amount of mercury, lead, nickel, arsenic and chromium was 0.417, 2.33, 0.064, 0.056 and 0.012 mg per lamp, respectively. Currently, waste of CFLs is disposed by municipal waste stream in waste landfills. For improving the current conditions, we propose by considering the successful experience of extended producer responsibility (EPR) in other electronic waste management. The EPR program with advanced recycling fee (ARF) is implemented for collecting and then recycling CFLs. For encouraging consumers to take the spent CFLs back at the end of the products’ useful life, a proportion of ARF (for example, 50%) can be refunded. On the other hand, the government and Environmental Protection Agency should support and encourage recycling companies of CFLs both technically and financially in the first place.     

Takakura composting method for food wastes from small and medium industries with indigenous compost

Environmental Science and Pollution Research - The current work aimed to study the physical, chemical and biological properties of food wastes generated from small and medium industries by using...     

Sustainable supplier selection for the cold supply chain (CSC) in the context of a developing country

Cold supply chain (CSC) is a process that involves temperature-controlled activities ranging from the acquisition of raw materials and down to the end consumers. A sustainable cold chain supplier is the one that incorporates sustainable practices in its complete cycle of operations. This is to ensure keeping the products from going to waste, especially in the case of a developing country. To identify the driving factors towards the sustainable cold chain supplier, this study utilizes the interpretive structural modelling (ISM) approach in the first phase. Fifteen various sustainability factors were analyzed and the “utilization of renewable resources” factor concluded to be the most important driving factor. By implementing renewable resources, a supplier can be able to convert its manufacturing processes and services to sustainable assets. The second phase of this study conducts the selection of cold chain suppliers in the context of Pakistan. For this purpose, fuzzy VIKOR, a multi-criteria decision-making (MCDM) technique is incorporated to analyze eight suppliers based on fifteen distinct criteria. The results concluded Mitchell foods to be the most economically, environmentally and socially sustainable suppliers in the context of Pakistan. This study recommends providing business-friendly incentives to suppliers like Mitchells and new investors who tend to keep their operations sustainable by adopting renewable resources. Furthermore, the relaxation of taxes and creating job employability by working with sustainable suppliers can contribute positively towards economic growth and the overall society. The study holds novelty in the area of cold chain supplier selection for Pakistan by utilizing a novel approach in the form of ISM and fuzzy VIKOR techniques, thus forming a major application of this research study.

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Carbon and polymer-based magnetic nanocomposites for oil-spill remediation—a comprehensive review

Environmental Science and Pollution Research - Oil spills are a major contributor to water contamination, which sets off a significant impact on the environment, biodiversity, and economy....     

Sorption of carbendazim and linuron from aqueous solutions with activated carbon produced from spent coffee grounds: Equilibrium,kinetic and thermodynamic approach

Spent coffee grounds (SCG) have been used for the production of activated carbon (AC) by impregnation with different ratios of phosphoric acid at 600?°C, Xp (H₃PO₄/coffee): 3:1^30%, 4:1^30%, 3:1^50% and 4:1^50%. The obtained AC was characterized by BET, FTIR and SEM. BET surface area corresponds to 803.422 m² g^?1. The influences of the main parameters such as contact time, the pesticides initial concentration, adsorbent dose, pH and temperature on the efficiency of separation process were investigated during the batch operational mode. Results were modeled by adsorption isotherms: Langmuir, Freundlich and Temkin isotherms, which gave satisfactory correlation coefficients. The maximum adsorption capacities calculated from the Langmuir isotherms were 11.918?mg g^?1 for carbendazim and 5.834?mg g^?1 for linuron at room temperature. Adsorption kinetics of carbendazim and linuron have been studied by the pseudo-first-order, the pseudo-second-order and the intraparticle diffusion model. The results of adsorption kinetics have been fitted the best by pseudo-second-order model. The resulted data from FTIR characterization pointed to the presence of many functional groups on the AC surface. SCG adsorbent, as an eco-friendly and low-cost material, showed high potential for the removal of carbendazim and linuron from aqueous solutions.     

α-Amylase and α-glucosidase inhibitor effects and pancreatic response to diabetes mellitus on Wistar rats of Ephedra alata areal part decoction with immunohistochemical analyses

Ephedra alata, known as a medicinal plant in China, was used in this study as aqueous extract from aerial parts, for diabetes mellitus treatment. This study was carried out on two parts, in vitro, we tested the effect of the studied extract on the inhibition of α-glucosidase and α-amylase activities, and in vivo on Wistar male rats receiving alloxan intraperitoneally at a rate of 125 mg/kg. Extract (100, 200, and 300 mg/kg of body weight) was administrated for 28 days by oral gavage. Blood glucose, amylase, lipase, and lipid profile level were determined. Oxidative stress was evaluated by enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and by estimation of lipid peroxidation and protein carbonyl (PC) level. Histopathological changes in pancreas were investigated under photonic microscopy using immunohistochemical procedure. Our findings showed that aqueous extract inhibited in vitro both α-glucosidase and α-amylase activities and its use in vivo at 300 mg/kg of body weight restored pancreas weight and weight gain, ameliorated significantly (p ? 0.05) biochemical parameters; it prevented the increase in lipid and protein oxidation and the decrease in enzymatic and non-enzymatic defense system. Histological study of treated animals showed a comparable healed regeneration of beta cells.