Thai Environmental Engineering Journal

Sustainable Indicators of Water Resource Development Projects in Conservation Areas, Thailand

2024-06-13T14:08:20+07:00

Water resources development in Thailand is a very considerable aspect due to high variation of hydrological regime. Responsible agencies have to sufficiently supply in terms of quantity and quality raw water for various needs including water supply, agriculture, as well as industrial and other uses. Development of a water reservoir is one of the efficient
measures as for water source, in spite of some limitations. Unfortunately, the appropriate locations of potential reservoirs are mostly located in the natural resources conservation area occupied with the abundantly good ecological system, which might lead to the conflict of interest between the line agencies of water resources development and natural resources conservation. Despite the national laws and policies specify to promote sustainable water resource development, specific guidelines and standards for quantity-based consideration of sustainability together with the balance between resources development and conservation of a potential project have not yet been defined in details.

Consequently, the quantitative criteria to establish the sustainable water resource development indicators, applying the principles of self-sufficiency economy and transitioning from the extreme development of high into moderate impact levels with self-sustaining development, will ensure that the future water resources project development can be carried out successfully and effectively towards sustainability. The study is qualitative research using the Del Phi method. The Del Phi’s panel comprised selective 20 experts of various related ields, governmental agencies and independent academia. The research conducted firstly by defining draft relevant dimensions, factors, and indicators drawn from the previous related researches, and from in-depth interviewing 7 experts of the key related fields. Then the additional indicators and their scoring ranges were intensively determined and classified from the data and information of the 30 reservoirs’ environmental impact assessment (EIA) reports as well as those referenced from the relevant researches, governmental agencies’ regulations and announcements. The draft final indicators and scoring ranges were summarized and proposed to the Del Phi’s panel not less than two rounds to obtain their majority conclusion on indicators, weighting factors, scoring ranges and recommendations of sustainability level for the future projects.

The study results indicated that the relative importance weighting of four dimensions to be considered were : engineering (20%), natural resources and environment (35%), social (25%), and economics (20%). This research identified 14 main factors of which 7 factors having high significance, including (1) wildlife, (2) forests, (3) ecology system, (4) number of affected people, (5) quality of life, (6) economic feasibility, and (7) social opposition. These 14 factors comprise a total of 29 key indicators, with 12 highly significant indicators including (1) uniqueness, (2) number of opponents, (3) water quality, (4) annual cultivated area per reservoir capacity, (5) design flood rate per reservoir capacity, (6) environmental economic feasibility, (7) economic feasibility, (8) proportion of beneficiaries on sufferers, (9) conservation area type, (10) Number of evacuated households per unit of reservoir capacity, (11) endangered wildlife, and (12) biodiversity of wildlife.

Investigating the Impact of Aeration and Leachate Recirculation for Biodrying of Food and Vegetable Waste from the Market

2024-05-23T20:08:27+07:00

The increasing production of waste from the market presents significant challenges for waste management, necessitating efficient treatment methods like biodrying. This study examines optimizing biodrying methodologies for the treatment of fruit and vegetable waste collected from market sources, emphasizing the nuanced impact of leachate recirculation within zero discharge systems. Aimed at bolstering the efficiency of converting market refuse into a biodried product suitable for integration into the waste-to-energy framework, our research meticulously assessed the performance of three lysimeters, arranged in parallel, under distinct aeration rates: Lysimeter 1 with an aeration rate of 0.2 m³/kg/day, followed by Lysimeters 2 and 3 with 0.4 m³/kg/day and 0.6 m³/kg/day respectively. Lysimeter 1 emerged as the front-runner, showcasing better performance metrics across CO₂ concentration, weight reduction, leachate volume, and temperature profiles. Notably, it achieved a remarkable 5.97% moisture content (MC) reduction at the lowest aeration rate of 0.2 m³/kg/day. The controlled aeration strategy employed in Lysimeter 1 facilitated significant organic content transformation and led to an impressive 317% boost in heating value, surpassing the results of Lysimeters 2 and 3, which recorded MC losses of 7.97% and 2.47%, respectively. These findings highlight the critical importance of optimizing aeration rates and the detrimental effects of leachate recirculation on the biodrying process. They advocate for future research endeavors to refine aeration rates further and exclude leachate recirculation, aiming to produce a biodried product that meets the moisture loss and heating value requirements for the cement industry's RDF standards. This study contributes valuable insights towards enhancing biodrying efficiency, with significant implications for waste management and energy recovery practices.

Impact of Feedstock Density on Biodrying for Enhancing Heat Retention and Moisture Reduction

2024-07-11T11:41:20+07:00

This study examines the effect of varying feedstock densities on the performance of biodrying processes to enhance waste management efficiency. Three different densities of wet- refuse-derived fuel 3 (wet-RDF3) from Bangkok's On Nut Transfer Station were tested using lysimeter reactors with constant aeration rates (0.6 m³/kd.day). Results revealed that a moderate density (230 kg/m³) achieved the highest temperature integration index (7218.01°C) and demonstrated effective moisture reduction and minimal volatile solids consumption. The higher densities improved heat retention and prolonged thermophilic conditions, optimizing the biodrying process. These findings highlight the importance of feedstock density in biodrying, suggesting that optimal density can significantly improve waste drying efficiency and produce better quality refuse-derived fuel. This approach offers a sustainable solution for waste management, particularly in developing countries.

The Effect of Bromide Ions on the Formation of Brominated Haloacetic Acids (Br-HAAs) in Tropical Rivers, Thailand

2024-07-01T15:40:17+07:00

With the presence of bromide ions in chlorination during water purification, hypobromous acid (HOBr) is formed, leading to the formation and distribution of brominated disinfection by-products (Br-DBPs) in tap water. Brominated haloacetic acids (HAAs) in tap water are known to be significantly harmful and toxic to human health. Bromide ions are naturally present in groundwater and surface water, primarily as affected by seawater intrusion. Conventional treatment methods face difficulty in completely eliminating bromide ions. This study investigated the concentration of bromide ions and the haloacetic acid formation potentials (HAAFPs) in three tropical river sources in Thailand: the Tha-Chin River, the Chao Phraya River, and the Mae Klong River. The bromide ion concentrations were 44.79, 41.34, and 18.22 µg/L, respectively. In these three rivers, chlorinated and brominated HAAs (trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), bromodichloroacetic acid, and bromochloroacetic acid) were detected after chlorination. The sum of only DCAAFPs and TCAAFPs were significantly higher than the US EPA regulations of 60 µg/L for total HAA5 (the sum of monochloroacetic acid, monobromoacetic acid, DCAA, dibromoacetic acid, and TCAA). The DCAAFPs in the Chao Phraya River were relatively high, surpassing the WHO guidelines of 50 µg/L. This study also found that the Tha-Chin River had high levels of bromide ions and brominated HAAFPs, resulting from seawater intrusion from the estuary Gulf. These findings highlighted the formation of brominated HAAFPs, which were particularly significant in water sources with higher levels of bromide ions in the water.

Effect of In-situ Aeration on Leachate Qualities under Uncompacted Municipal Solid Waste Disposal Conditions

2024-08-15T15:27:25+07:00

This research was carried out to investigate the effect of in-situ aeration on leachate qualities in simulated lysimeters containing uncompacted municipal solid wastes representing typical municipal solid waste disposal conditions in Thailand. The study was performed by applying different aeration conditions to the lysimeters and leachate volume and its chemical characteristics were monitored over 6 months. The air supply conditions varied from natural ventilation to active aeration at rates of 0.18 and 0.36 l/min. The generated leachate was compared to the control lysimeter representing typical anaerobic disposal conditions. The lysimeters operated at a high airflow rate of 0.36 l/min and natural ventilation had their leachate qualities in terms of organic (BOD, COD) and nitrogen (TKN) well stabilized by more than 90% within 30 days. Under low aerated conditions (0.18 l/min), organic stabilization in leachate required more than 100 days whereas TKN removals were also highly fluctuated. Based on the results from this study, waste disposal operation under natural aeration through a ventilation pipe installed into the uncompacted waste layer would be sufficient to reduce organic and nitrogen pollutants in leachate to the same level as the highly aerobic landfill condition.

Assessment of Airborne Microbial Contamination in Cosmetics Manufacturing Facilities: Skincare Cream Production in Thailand

2024-08-22T09:30:49+07:00

Skincare is a variety of practices to maintain skin integrity, enhance appearance, and alleviating skin conditions. Thailand's skincare market has seen substantial growth, becoming the dominant sub-sector in cosmetics. Microbial contamination in the skincare can occur when the manufacturing process are not well controlled. The objective of this research is to establish criteria for managing appropriate levels of microbial quantities in the air of Good Manufacturing Practice (GMP) cosmetics production facilities. Airborne microbial samples are collected using both active air sampler and settle plate techniques at varying time intervals, followed by a comparative analysis. The skincare creams as representatives showed that the total airborne microbial counts using the air sampling method, ranged from 85 to 252 cfu/m³. For the settle plate method for 4 and 1 hours ranged from 8 to 90 cfu/4h and 1 to 59 cfu/h. The action limits from control charts at 341 cfu/m³, 107 cfu/4h, and 59 cfu/h for the respective methods. Based on the results of this research, it can be concluded that the monitoring criteria for cosmetics manufacturing facilities, with a specified limit for airborne microbial counts not exceeding 100 cfu/4h (sterile medicinal products at Grade D) or 50 cfu/h (moderate IMA level).

Adsorption Mechanisms of Haloacetonitriles on Adsorbent Derived from Canvas Fabric

2024-06-17T23:06:47+07:00

The adsorption mechanisms of HANs on canvas fabric-derived adsorbent and modified adsorbent with ferric chloride and ferric nitrate solution were investigated. With the ferric nitrate modification (CF-Fe(NO₃)₃), the pore structure of the adsorbent was mesopore, while other adsorbents were micropore. With the mesopore structure of CF-Fe(NO₃)₃, the adsorption occurred both on the outer pore layer and inside the pore surface, which resulted in the highest adsorption efficiency obtained by the CF-Fe(NO₃)₃ adsorbent. Furthermore, the adsorption mechanisms of five HAN species were investigated. Physical adsorption is the main mechanism of HANs on CF-Fe(NO₃)₃ adsorbent based on the low adsorption energy determined from the D-R isotherm. The fastest HAN species to reach equilibrium and the highest removal by the CF-Fe(NO₃)₃ adsorbent was TCAN, which has the lowest solubility and more hydrophobicity. Besides the low solubility of HANs species, the halogen atom of each HANs species also affected the removal efficiency. HANs species with more halogen atoms showed higher removal efficiency than other HANs species with low halogen atoms.

Performance Assessment of the Onsite Wastewater Treatment System at High-rise Condominium in Bangkok: A Case Study

2024-08-14T11:17:53+07:00

Condominiums in Bangkok increase annually to accommodate the growing population. The wastewater generated from residents’ activities could potentially impact natural water quality. This study aims to assess the efficiency of onsite wastewater treatment from the high-rise condominium in Bangkok and investigate the presence of microplastic contamination in discharged wastewater. The revealed removal efficiencies of SS, VSS, BOD, COD, NH₄-N, and TN at 82.75%, 81.55%, 94.80%, 85.60%, 75.0%, and 21.4%, respectively. The E. coli could be treated at 1.44log₁₀. The effluent's pH, SS, and BOD values met the wastewater effluent standards according to the notification of the Ministry of Natural Resources and Environment on effluent standards from buildings of certain types and size. The presence of microplastics in wastewater originating from the high-rise condominium building is detected in both influent and effluent, at quantities of 4 pieces/L and 2 pieces/L, respectively. Fiber-shaped microplastics were found the most, followed by fragments, films, and granules, in that order. The random sampling of microplastics for analysis to identify the polymer type revealed the presence of Polyethylene terephthalate (PET), Polypropylene (PP), Low Density Polyethylene (LDPE), and detected Polydimethylsiloxane (PDMS).