The objective of this study was to evaluate the composition and characteristics of the generated municipal solid waste (MSW) in order to obtain information about the quantity of recoverable plastic at Bukit Bakri landfill Muar, Malaysia. Solid waste sampling and laboratory analysis were carried out according to the random sampling method based on American Society of Testing and Materials (ASTM) standards to determine the waste compositions and proximate analysis (moisture content, volatile matter, ash content and fixed carbon). The total quantity of MSW generated at the site was 330 ton/day made up of 25 individual types of waste. The main compositions of the generated waste were 39% food waste, 12% plastic waste and 16% paper which accounted for about 67% by weight. About 12% of disposed materials at Bakri landfill consisted of recoverable plastics of which 9% plastic film, 2% rigid plastic and 1% plastic foam. The average moisture content of the waste was between 50-58%. Although, there is significant volume of recoverable plastic at the disposal site (approximately 35 tons/day), this materials are still being land filled without any form of treatments. Based on the results obtained, this study has recommended the plastic recovery plan as a feasible MSW strategy to reduce the amount of disposed waste at Bakri landfill.

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Potential genotoxic effects of diffusion flame-derived particulate matters (PMs), known to cause various adverse health problems, doped with iron, one of the representative heavy metals frequently found in the atmosphere, were examined. B6C3F1 mice were exposed to PMs [chamber 1 (low), 100; chamber 2 (middle), 200; and chamber 3 (high), 400 microg/m3] for 6 h/day, 5 days/week for one, two and four weeks in 1.5 m3 whole-body inhalation chambers. Our diffusion flame system produced 94.8 and 5.2% fine PM2.5 and PM10, respectively, with 89% of PM2.5 sized between 0.1 and 0.2 microm. Two cytogenetic endpoints were investigated through chromosomal aberration and supravital micronucleus (SMN) assays. Frequencies of cells with chromosome aberration (%) were observed in time- and concentration-dependent manners except in one-week exposure group, as also observed in SMN study. Generally, noniron flame induced less chromosome aberration than iron-doped flame, an indication that iron particles could potentiate urban PM toxicity. The above results indicate our diffusion flame system generated genotoxic fine PMs, whose effects were potentiated by organometallic particles such as iron. Our system can provide reliable PM models for studying the toxicity of urban fine PMs applicable for risk assessment.

Granite, bentonite, and starch were mixed with clinoptilolite zeolite to produce a modified zeolite. The modified zeolite was tested for its ability to absorb formaldehyde from air. The modified sample formaldehyde adsorption capacity was then compared with those of commercially available clinoptilolite, faujasite (Y), mordenite, and zeolite type A. Studies were focused on the relationships between the physical characteristics of the selected zeolites (crystal structure, surface porosity, pore volume, pore size) and their formaldehyde adsorption capacity. The removal of starch at high temperature (1100°C) and addition of bentonite during modified clinoptilolite zeolite (M-CLZ) preparation generated large pores and a higher pore distribution on the sample surface, which resulted in higher adsorption capacity. The formaldehyde adsorption capacities of M-CLZ, clinoptilolite, faujasite (Y), zeolite type A, and mordenite were determined to be 300. 5, 194.5, 123.7, 106.7, and 70 mg per gram of zeolite, respectively. The M-CLZ, clinoptilolite, and faujasite (Y) crystals contained both mesoporous and microporous structures, which resulted in greater adsorption, while the zeolite type A crystal showed a layered structure and lower surface porosity, which was less advantageous for formaldehyde adsorption. Furthermore, zeolite regeneration using microwave heating was investigated focusing on formaldehyde removal by desorption from the zeolite samples. XRD, XRF, N 2 adsorption/desorption, and FE-SEM experiments were performed to characterize the surface structure and textural properties the zeolites selected in this study.