Source Contribution of 1,3 Butadiene in the Vicinity of Petrochemical Industrial Area

Emissions and ambient concentrations of 1,3 butadiene released from the synthetic rubber industries in the largest petroleum and petrochemical complex in Thailand were evaluated in this study. The industrial emissions in this analysis were those emitted from process fugitive, combustion stack, flare, and wastewater treatment facility. It was found that wastewater treatment units were the largest emission source among other potential sources. The contribution of emission from wastewater treatment plants were about 92% of total 1,3 butadiene emission. The extent and magnitude of 1,3 butadiene in ambient air were further evaluated through the simulation of AERMOD dispersion model using these emission data together with local meteorological and topographical characteristics. Predicted annual 1,3 butadiene concentrations at every receptor were lower than its ambient air quality standard (< 0.33 μg m-3). Source apportionment analysis was performed with the objective to reveal the contribution of each emission source to the ambient concentrations at each receptor. Analytical results indicated that wastewater treatment units were the major emission source affected to the environmental concentrations of 1,3 butadiene in the study area. Evaluation of the potential adverse health impact of this chemical revealed that there may be a potential carcinogenic risk from inhalation exposure of 1,3 butadiene. Therefore, an effort in controlling emission of 1,3 butadiene should be given the priority to effectively manage the level of this compound in the environment

SOLIDIFICATION/STABILIZATION OF NONVALUABLE RESIDUE FROM WASTE PRINTED CIRCUIT BOARD ASSEMBLY

ABSTRACT: The process of copper recovery from waste printed circuit board assembly (PCBA) has remained a large fraction of solid waste called &quot;Nonvaluable Residue (NVR)&quot;. This residue is considered to be a hazardous waste because Pb, Cu, and Sb exceed the regulatory levels. Solidification/Stabilization (S/S) treatment technique is selected to improve waste characteristics before disposal of in hazardous waste landfills. In this study, a cement-based solidification/stabilization was used to treat NVR. Unconfined compression strength test (UCS) and toxicity characteristic leaching procedure (TCLP) were mainly used for physical and chemical characterization of the solidified/stabilized products. After curing for 28 days, the compressive strength and heavy metal leachability (Pb, Cu, Sb) were tested. The results showed that the compressive strength of blank sample was 20.75 MPa while compressive strengths of the solidified/stabilized NVR products were 7.36, 4.17 and 1.35 MPa for 20%, 30% and 40 wt% of NVR, respectively. All experimental mixture ratios satisfied the UCS requirements (0.35 MPa). In addition, the concentrations of Pb, Cu, and Sb in the TCLP leachate of all solidified/stabilized NVR products were lower than the limit value and the original waste. This study indicated that cement-based S/S treatment process was able to improve heavy metal immobilization and subsequently minimize potential environmental impacts in landfill disposal

Comparison of Performance and Economic Efficiency for Greenhouse Solar versus Hot Air Drying: A Case of Crispy Mango Production

This study aimed to compare the performance and economic efficiency of greenhouse solar and hot air drying. These are widely used and inexpensive techniques for preserved fruit production in Thailand. Two drying methods were used to dry mango fruit, var. Nam Dok Mai. During the process of both drying methods, the moisture content of mango slices was reduced from an average 85.6% to 12.5% wet basis. To determine the most profitable dryer system for investment, economic analyses of greenhouse solar and hot air drying, involving the main variables affecting their profitability, were investigated, including production and maintenance cost, capital costs, revenue, and drying capacities. The internal rate of return (IRR), net present value (NPV), benefit to cost ratio (BCR) and payback period (PBP) were all evaluated. The results of economic evaluation revealed that high values of IRR, NPV, and BCR, and low value of PBP made the two drying systems cost efficient. However, when the incremental rate of return (ROR) was determined, 66% incremental ROR was much greater than the minimum attractive rate of return (MARR = 4.875%). Consequently, the greenhouse solar drying method proved to be the most suitable method for small-to-medium-scale entrepreneurs to produce crispy mango

Integration of substance flow analysis, transport and fate of materials in the environment, and environmental risk assessment for provision of information for regional environmental management: cadmium as a case study in Australia

Extraction, production, utilization and disposal of material resources have been undertaken continuously for much of human histories. Unavoidably, all of these activities have disturbed our environment, and subsequently have been harmful to humans and ecosystems in this and future generations. Due to time lag associated with both environment impact and the effects of measures taken to reduce this impact, existing approaches (i.e. monitoring and reacting) do not give sufficiently rapid feedback for effective environmental management. With regard to the complexity and concern related to environment-health chain effects, there is currently no environmental tool or approach that can provide comprehensive information and indicators covering all major environment and health themes, to enable decision makers to make informed judgements about regional policies and plans, relating to the sustainable use and disposal of material resources. Consequently, there is a need for developing a new approach by taking account of a multidisciplinary concept used in this thesis.Substance Flow Analysis (SFA) has been mainly applied in order to provide input information for Health Risk Assessment (HRA). The SFA approach provides the quantity of the substance that is transported (flows) and stored in the system (stock), and of which sub-system, flow, and process is the greatest concern. The HRA approachprovides estimates of human health risk associated with site, activity and facility. An environmental fate and transport model is another key knowledge area incorporated into the HRA process.An integrating method of SFA, environmental fate and transport, and HRA is developed and illustrated by a case study of cadmium in Australia.This thesis shows that this new integration of existing stand-alone methods can provide holistic information and useful indicators covering all significant economic activities, environment, flows, and health risk assessment for selected substances. This enables better decision making on the use and disposal of substances at a range of levels in the economy, from corporations to regions and nations