Management of hazardous waste in Thailand: present situation and future prospects

 This paper deals with the present scenario of hazardous waste management practices in Thailand, and gives some insights into future prospects. Industrialization in Thailand has systematically increased the generation of hazardous waste. The total hazardous waste generated in 2001 was 1.65 million tons. It is estimated that over 300 million kg/year of hazardous waste is generated from nonindustrial, community sources (e.g., batteries, fluorescent lamps, cleansing chemicals, pesticides). No special facilities are available for handling these wastes. There are neither well-established systems for separation, storage, collection, and transportation, nor the effective enforcement of regulations related to hazardous wastes management generated from industrial or nonindustrial sectors. Therefore, because of a lack of treatment and disposal facilities, these wastes find their way into municipal wastewaters, public landfills, nearby dump sites, or waterways, raising serious environmental concern. Furthermore, Thailand does not have an integrated regulatory framework regarding the monitoring and management of hazardous materials and wastes. In addition to the absence of a national definition of hazardous wastes, limited funding has caused significant impediments to the effective management of hazardous waste. Thus, current waste management practices in Thailand present significant potential hazards to humans and the environment. The challenging issues of hazardous waste management in Thailand are not only related to a scarcity of financial resources (required for treatment and disposal facilities), but also to the fact that there has been no development of appropriate technology following the principles of waste minimization and sustainable development. A holistic approach to achieving effective hazardous waste management that integrates the efforts of all sectors, government, private, and community, is needed for the betterment of human health and the environment. Received: February 26, 2001 / Accepted: October 11, 2002     

Emission of dioxins/furans and other U-POPs from test burns of non-POP pesticides in a hazardous waste incinerator

This paper presents the results of test burns for obsolete pesticides (OPs) of the permethrin group in a high temperature incinerator (HTI) in Southeast Asia. Three test burn runs were conducted, a baseline run when no OP was fed to the incinerator, and two test runs with different mixtures of OP compounds (formula 1 and 2, refer to Table 1 for detail) containing chlorine in the feeding wastes. The unintentional formed persistent organic pollutants (U-POPs) including 17 dioxins/furans, 12 dioxin-like PCBs and 12 chlorobenzenes (CBs) were monitored in all input materials and all discharges (flue gas, scrubbing liquid and solid residues). The results show relatively high levels of the U-POPs in the flue gas emission with total dioxins/furans of 4.4, 3.4, and 8.4 ng I-TEQ/m³ in the baseline, test run 1 and test run 2, respectively, which are above international acceptable emission levels. The PCB levels in flue gas were, respectively, 0.01, 0.3 and 0.4 ng I-TEQ/m³. The baseline thus had similar U-POPs levels with the OP test runs.In stack emission, approximately 90% of the U-POPs and 100% of CBs were present in gas phase. The emission factors, mass of pollutants per metric ton (tonne) of input waste, of U-POPs associated with fly ash (from bag house) were the highest, followed by flue gas and bottom ash while those associated with scrubbing liquid were relatively low. Among the waste input material only the black toner power contained U-POPs, but at low levels. The profiles of the dioxins/furans and PCBs in the toner waste were significantly different from that in the discharges. Despite the overall good destruction and removal efficiency of permethrin (better than 90%) the high emission of U-POPs and CBs from the test burn is of another more serious concern. To our best knowledge the findings of this study are the first of this kind for the Southeast Asia. The findings emphasize that if not properly conducted a standard destruction technology of a non-POP chemical can lead to a release of a range of more dangerous U-POPs into the environment.     

Productive utilization of pig farm wastes: a case study for developing countries

This paper presents a case study on pig farm waste management in which pig manure is stabilized in two-stage anaerobic reactors (to produce methane), while pig farm wastewater is treated in water hyacinth ponds from which the harvested water hyacinth plants are used in the production of silage (animal feed) or compost fertilizer. The results suggest the technical feasibility of applying these technologies to treat and recycle pig farm wastes. Cost/benefit analysis reveals the option to produce methane gas and silage to be financially viable after 15 years of operation. A management concept of waste recycling programs is presented, including relationships among objectives, constraints and implementation plan. Decision on a waste recycling program should not be based only on cost/benefit analysis, but also on the pollution control and public health improvement to be gained.     

Sulfide production during anaerobic lagoon treatment of tapioca wastewater

Laboratory-scale experiments on anaerobic lagoon treatment of tapioca wastewater were conducted under ambient, tropical conditions. The objectives of this study were to investigate factors that affect hydrogen sulfide production and to propose means to control the formation of hydrogen sulfide in lagoon effluents. The concentrations of sulfides were found to increase with increasing organic loading from 2.76 to 5.77 kg COD/m³.d, decreasing hydraulic retention time; and increasing pH from 3 to 7. The maximum total sulfide concentration of 18.8 mg/L occurred at the organic loading of 5.77 kg COD/ m³.d and neutral pH. the maximum H₂S concentration was calculated to be 13.3 mg/L which occurred in the laggoon operated at an organic loading of 5.77 kg COD/m³.d and a pH of 5. The control of odour problems due to the H₂S formation should be possible by raising pH of the lagoon water to be more than 8 or operating the lagoon at low organic loadings.     

Determination and health risk assessment of enrofloxacin,flumequine and sulfamethoxazole in imported Pangasius catfish products in Thailand

The goals of this study were to determine the levels of three antibiotics – enrofloxacin, flumequine and sulfamethoxazole – in Pangasius catfish products imported into Thailand and to assess the health risks from consumption. To extract these antibiotic residues, acetonitrile, methanol and a small amount of formic acid were used as solvents. Determination of the antibiotics after extraction steps was carried out by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) technique. The results showed that 14 and 3 samples of Pangasius catfish products were contaminated with enrofloxacin and sulfamethoxazole, respectively. No flumequine residue was found. While the concentration levels of these antibiotics in most contaminated samples were lower than the European Union (EU) standard, one sample was found to contain sulfamethoxazole at 245.91 µg kg^?1, which was higher than the EU standard (100 µg kg^?1), indicating the likelihood that some contaminated freshwater fish products are widely distributed in Thai markets. Notably, the concentration levels of enrofloxacin in samples of Pangasius catfish with skin were higher than in non-skin products, suggesting that products with skin might retain more antibiotic residues than non-skin products. Although the hazard quotient showed that consuming imported Pangasius catfish products, based on the current consumption rate, will not adversely affect consumer health, antibiotic residues in Pangasius catfish products imported into Thailand should be continually monitored.     

OPTIMIZATION OF DUAL-MEDIA FILTER PERFORMANCE1

ABSTRACT: Rapid-rate filter with sand or anthracite as filter media was studied at filtration rates of 4.5 and 9.0 m³/m²-h. Different parameters were evaluated by adopting a proposed simplified model. A suitable combination of anthracite-sand as filter media was given by using corresponding filter parameters of single-medium filters and break-even optimization technique.     

Paraquat adsorption, degradation, and remobilization in tropical soils of Thailand

Paraquat adsorption, degradation, and remobilization were investigated in representative tropical soils of Yom River Basin, Thailand. Adsorption of paraquat in eight soil samples using batch equilibration techniques indicated that adsorption depended on soil characteristics, including exchangeable basic cations and iron content. Multiple regression analysis indicated significant contribution of exchangeable calcium percentage (ECP), total iron content (TFe) and exchangeable sodium percentage (ESP) to paraquat sorption (Q). ESP and TFe were significant at all adsorption stages, whereas ESP was significant only at the initial stage of paraquat adsorption. Adsorption studies using two soils representing clay and sandy loam textures showed that paraquat adsorption followed the Freundlich model, exhibiting a nonlinear sorption curve. Paraquat adsorption was higher in the clay soil compared to the sandy loam soil with Kf values of 787 and 18, respectively. Desorption was low with 0.04 to 0.17% and 0.80 to 5.83% desorbed in clay and sandy loam soil, respectively, indicating some hysteresis effect. Time-dependent paraquat adsorption fitted to the Elovich kinetic model indicated that diffusion was a rate-limiting process. Paraquat mobility and degradation studies conducted using both field and laboratory soil column experiments with clay soil showed low mobility of paraquat with accumulation only in the surface 0-5 cm layer under field conditions and in the 0-1 cm layer in a laboratory soil column experiment. Degradation of paraquat in soil was faster under field conditions than at ambient laboratory conditions. The degradation rate followed a first-order kinetic model with the DT50 at 36-46 days and DT90 around 119-152 days.     

INTEGRATED PLANNING OF RURAL WATER SUPPLY AND SANITATION1

ABSTRACT: Development schemes to improve the health of the rural populace through prevention of the transmission of communicable diseases should be considered in the context of some kind of “Sanitation Package” to ensure effectiveness. The general practice of concentrating resources on limited objectives, like water quality improvement, is shown to be less effective than allocating the same resources to multi-objectives defined in the Sanitation package. Systems Dynamic Modeling based on the DYNAMO II language, is presented as a capable tool for sanitation systems planning.     

Characteristics of Gases Emitted from Chicken Manure Wastewater and Potential Effects on Human Health

Environmental Science and Pollution Research - Hazardous and odorous gas emissions from chicken manure wastewater are a public preoccupation. Odor composition measurements are crucial steps to...