Overview of waste disposal and landfills/dumps in Asian countries

Many cities in developing Asian countries face serious problems in managing solid wastes. The annual waste generation increases in proportion to the rises in population and urbanization. Asian countries with greater rural populations produce more organic waste, such as kitchen wastes, and fewer recyclable items, such as paper, metals, and plastics. Reliable data on solid waste compositions are difficult to obtain, and even if available, they are often not updated. We report the most recent waste composition data in some developing Asian countries. We suggest that a better classification system for landfills is needed to address inconsistencies in data for sanitary landfill sites versus waste dumps. We also discuss the information on waste disposal trends and problems associated with general solid waste management in developing Asian countries.     

Assessment of antimicrobial activity of Catechu and its dyed substrate

The present study was undertaken to evaluate the antimicrobial activity of catechu in solution and % microbial reduction of dyed wool samples against Escherichia coli MTCC 443, Staphylococcus aureus MTCC 902, Candida albicans ATCC 10261 and Candida tropicalis ATCC 750, by using micro-broth dilution method, disc diffusion assay and growth curve studies. The dye showed the maximum antimicrobial activity at 20% w/v, inhibiting the microbial growth by more than 90%. In the next set of the experiments the antimicrobial activity of the dye was compared on woollen yarn alone and on pre-mordanted samples. The reduction in antimicrobial activity was observed when mordanted samples were examined. K/S, CIELab values and fastness properties of the dyed samples were assessed. The structural morphology of woollen yarn was also evaluated using scanning electron microscopy (SEM). Haemolytic activity on human erythrocytes was studied to exclude possibility of further associated cytotoxicity. The observed antimicrobial characteristics and negligible cytoxicity of catechu indicate that the dye might be a promising antimicrobial agent for developing bioactive textile materials and clothing.     

Food additives for the synthesis of metal nanoparticles: a review

Environmental Chemistry Letters - Metal nanoparticles have found applications in many fields such as molecular diagnostics, electronic devices and environmental remediation. Nonetheless,...     

Production and growth of microalgae in urine and wastewater: A review

Environmental Chemistry Letters - Issues of climate change, energy demand, and natural resources depletion are calling for circular methods to produce value-added products such as biomass, biofuel,...     

Relationship between Pb and Cd accumulations in house crow,their habitat,and food content from Klang area,Peninsular Malaysia

Heavy metal pollution has become a global concern due to accumulation in tissue and transferable effects to humans via the food chain. This study focused on monitoring the accumulation of cadmium (Cd) and lead (Pb) in surface soil and body content: bone, heart, brain, liver, lung, muscle, kidney, feathers, feces, and gizzard contents of house crow Corvus splendens in the Klang region, Malaysia. The results revealed the occurrence of Pb and Cd in all biological samples from house crows, food contents, and surface soil samples. Heart and kidney accrued high amounts of Cd, while high amounts of Pb were found to accumulate in bones and feathers. Major discrepancies were also discovered in the concentrations of metals between juvenile and adults, as well as female and male bird samples. Concentrations of Pb and Cd in house crow internal tissues correlated significantly with that of bird feathers, but none could be established with that of surface soil. In addition, a significant correlation was observed between Pb concentration in the internal tissues to that of the feces, but the same was not the case when compared with the surface soil concentration. Metal accrual in the house crows feathers and feces may be through a long-term transmission via the food chain, which are eliminated from feathers via molting. This may suggest the utility of molted breast feathers of house crow in the bio-monitoring of Cd and Pb contamination, whereas feces of house crow appear only to be suitable for the bio-monitoring of Pb contamination.     

Performance of biotic indices in comparison to chemical-based Water Quality Index (WQI) in evaluating the water quality of urban river

In order to evaluate the water quality of one of the most polluted urban river in Malaysia, the Penchala River, performance of eight biotic indices, Biomonitoring Working Party (BMWP), BMWP^Thai, BMWP^Viet, Average Score Per Taxon (ASPT), ASPT^Thai, BMWP^Viet, Family Biotic Index (FBI), and Singapore Biotic Index (SingScore), was compared. The water quality categorization based on these biotic indices was then compared with the categorization of Malaysian Water Quality Index (WQI) derived from measurements of six water physicochemical parameters (pH, BOD, COD, NH₃-N, DO, and TSS). The river was divided into four sections: upstream section (recreational area), middle stream 1 (residential area), middle stream 2 (commercial area), and downstream. Abundance and diversity of the macroinvertebrates were the highest in the upstream section (407 individual and H′?=?1.56, respectively), followed by the middle stream 1 (356 individual and H′?=?0.82). The least abundance was recorded in the downstream section (214 individual). Among all biotic indices, BMWP was the most reliable in evaluating the water quality of this urban river as their classifications were comparable to the WQI. BMWPs in this study have strong relationships with dissolved oxygen (DO) content. Our results demonstrated that the biotic indices were more sensitive towards organic pollution than the WQI. BMWP indices especially BMWP^Viet were the most reliable and could be adopted along with the WQI for assessment of water quality in urban rivers.     

Developing strategies for managing construction and demolition wastes in Malaysia based on the concept of circular economy

Construction and demolition (C&D) waste is a pressing issue not only in Malaysia, but it is also a worldwide concern including the developed countries as well. C&D waste should be managed throughout the construction cycle. The concept of circular economy (CE) is an emerging notion that has the potential to be utilized as waste minimization approach. This paper aims to assess the potentials of incorporating the CE concept as an approach to minimizing C&D wastes, by developing a CE-based theoretical framework for C&D waste management in Malaysia. In line with this objective, a systematic review has been conducted to determine how CE can be operationalised as a strategy to minimize wastes, while considering it as a key factor for mitigating the environmental impacts. Based on the literature review, a CE-based theoretical framework has been proposed using Malaysia as a case study. The framework has been developed following a three-layer approach namely micro-, meso-, and macro-levels. Waste minimization strategies have been identified for each level taking into account the main stages in the construction industry, i.e., planning, designing, procurement, construction, and demolition. The different stakeholders involved at each stage and their interactions in the stages have also been identified.     

Fabrication and Characterization of Polyaniline Based Nano-Composite with Their Physico-Chemical and Environmental Applications

A series of organic–inorganic conducting nano polymer-matrix composite cation-exchanger have been synthesized via sol–gel method and characterized through FTIR, XRD, TGA-DTA, SEM, and TEM studies. The structural studies confirm the semi-crystalline nature of the material but the morphology of the exchanger gets changed after incorporation of inorganic moiety. The particle size of the nano-composite was found to be 19.2 nm. The observed band gap for the different samples was found to be in the range of 3.70–4.61 eV which shows that nano-composite material covers semiconducting range but the resistivity of samples is highly dependent on the percentage of inorganic part in the composite. Further the oxidative degradation of the polymer backbone begins after the removal of trapped water successively followed by dopant and low molecular weight oligomers. During the antimicrobial screening, the nano-composite was found to be active against different strains of bacteria and fungi. Gel electrophoresis and molecular docking studies were carried out to check the interaction and mechanism of inhibition of microbial growth, respectively by studying the effect of the nano-composite with DNA-Topoisomerase-1.     

Medium-scale gasification of oil palm empty fruit bunch for power generation

Journal of Material Cycles and Waste Management - This paper focuses on the performance of oil palm empty fruit bunch (EFB) gasification using a medium-scale downdraft gasifier for power...     

Contribution of waste segregation to GHG emissions,land usage,and health risk of NMVOC exposure: a study in Malaysia

Journal of Material Cycles and Waste Management - The present study examined greenhouse gas (GHG) emissions, land usage, cost of land use, and health risk exposure to non-methane volatile organic...