Thai Environmental Engineering Journal

From Drainage to Regeneration: Revitalizing the Samsen Canal in Bangkok

Pechladda Pechpakdee — Wed, 24 Dec 2025 00:00:00 +0700

This study investigates the environmental condition and management challenges of the Samsen Canal, an inner-city waterway in Bangkok that currently functions primarily as a drainage channel. Water-quality monitoring at ten sampling stations revealed severe organic and microbial pollution, with BOD₅ and COD exceeding national standards, persistently low dissolved oxygen, and fecal coliform levels indicating continuous discharge of untreated wastewater. Spatial analysis identified hydraulic stagnation, sediment accumulation, and canal-bank encroachment as key physical constraints.

An integrated assessment using SWOT analysis, Stakeholder Influence Matrix, and the DPSIR framework under Integrated Water Resources Management (IWRM) principles was applied to evaluate technical and governance dimensions. The results show that canal management is limited by fragmented institutional responsibilities, inconsistent monitoring, and a continued emphasis on flood conveyance rather than pollution control and ecological function. The study concludes that future development should adopt a multifunctional canal approach, supported by centralized wastewater interception, hybrid blue–green–gray measures, and participatory management. Environmental engineers play a critical role in translating empirical evidence into coordinated actions to improve water quality, ecological performance, and urban livability.

Life Cycle Assessment of Municipal Solid Waste Management Systems in the ASEAN Region: Strategies toward Environmental Sustainability

Wed, 24 Dec 2025 00:00:00 +0700

Rapid urbanisation and consumption patterns shift in the Association of Southeast Asian Nations (ASEAN) has rapidly increased municipal solid waste (MSW) generation, resulting in environmental challenges such as greenhouse gas emissions, resource depletion and public health risks. This study evaluates the life cycle environmental impacts of MSW management systems in ASEAN, focusing on three areas of protection, including human health, ecosystem damage, and resource depletion, and translates these impacts into monetary units. Additionally, the study investigates mitigation potentials through the integration of circular economy policies. The environmental impacts associated with managing one tonne of MSW in ASEAN countries vary across countries, with impacts on human health varying from 6.60 x 10^-4 to 19.68 x 10^-4 DALYs (Disability Adjusted Life Years), on ecosystem quality ranging from 1.87 x 10^-6 to 3.31 x 10^-6 species-years, and resource depletion costs between -0.77 and 11.08 USD₂₀₁₃. Total environmental damage costs from managing one tonne of MSW in ASEAN countries range from 199.49 to 434.88 USD₂₀₂₃. The environmental costs of the MSW management sector in ASEAN countries range from 29 million to 24 billion USD₂₀₂₃ in 2024 and are projected to increase, ranging from 40 million to 28 billion USD₂₀₂₃ in 2030 and from 71 million to 38 billion USD₂₀₂₃ in 2050 if current systems remain unchanged. Indonesia faces the highest environmental costs in the region, due to its substantial MSW generation volume. Singapore is the only country that avoids environmental impacts from its MSW management systems, characterised by high recycling rates, significant energy recovery, and minimal landfilling. Circular economy has the potential to reduce the environmental costs by over 60%. Therefore, comprehensive reforms, including stringent landfill regulations and incentivised recycling practices, are essential to decrease reliance on open dumping and achieve sustainable waste management.

Logistics Efficiency Improvement and Waste Reduction using the Appropriate Forecasting Techniques Analysis for Hospital Pharmaceutical Demand Forecasting Error Reduction

Chatpon Mongkalig — Wed, 24 Dec 2025 00:00:00 +0700

Effective waste management is guided by the 7R framework (Refuse, Reduce, Reuse, Repair, Repurpose, Recycle, and Recover). This study emphasizes the first two most important principles (Refuse and Reduce) by improving pharmaceutical demand forecasting to reduce waste and enhance logistics efficiency. The objective of this research was to analyze the appropriate forecasting techniques for the case study hospital important pharmaceutical demand forecasting error reduction. Using ABC analysis, 219 products were classified, with Group A items (70.95% of total inventory value) selected for analysis. These were further categorized into cyclical/seasonal demand (31 SKUs) and demand without seasonality (188 SKUs). Randomized Complete Block Design (RCBD) was applied in the Design of Experiments (DOE) using the Analysis of Variance (ANOVA) and multiple comparisons test for the appropriate forecasting techniques analysis in order to reduce the important pharmaceutical demand forecasting error. The forecasting technique was the main factor and Mean Absolute Deviation (MAD) served as the response variable. According to the class A cyclical/seasonal demand pharmaceutical products, the most appropriate forecasting technique was the 12-month seasonal length Winters’ method. The average of MAD obtained by the yearly seasonal length Winters’ method decreased by 7.04 units per month comparing to the 3-month moving average which was the current forecasting method because of the seasonality of pharmaceutical demand. For the class A drugs without seasonality, the most appropriate forecasting technique was single exponential smoothing. The MAD of single exponential smoothing decreased by 38.47 units per month comparing to the 3-month moving average which was the as-is forecasting method of the case study hospital. It can be concluded that Winters’ method with 12-month seasonal length was suitable for cyclical/seasonal demand drugs, reducing MAD by 11% compared to the traditional 3-month moving average. For pharmaceutical demand without seasonality, single exponential smoothing was the most appropriate forecasting method, reducing MAD by 17.5%. The findings demonstrated that selecting appropriate forecasting methods could significantly improve logistics efficiency, reduce pharmaceutical waste, and enhance hospital supply chain performance.

An Innovative Method for Upcycling Leaf Waste from Green Areas in Bangkok's Government Agencies

Wed, 24 Dec 2025 00:00:00 +0700

The rapid growth of urban green spaces in Bangkok’s government agencies generates substantial amounts of organic leaf waste, which imposes significant financial burdens and environmental challenges when managed through conventional disposal methods. This study quantifies leaf waste generation in three government agencies and evaluates its potential valorization into composite panels as a sustainable alternative to plywood. Over a 30-day period, daily leaf waste generation ranged from 86.50 to 172.33 kg, highlighting a consistent biomass stream with high potential for reuse. Composite panels were fabricated by combining leaf waste with a urea-formaldehyde adhesive and a paraffin emulsion and then hot-pressed into 30 × 30 × 3 cm sheets. Mechanical testing revealed an average tensile strength of 0.063 MPa and a compressive strength of 5.45 MPa, values that are below the Thai Industrial Standard (TIS 966-2547) for Medium-Density Fiberboard (MDF) requirements for structural applications but are acceptable for lightweight, non-load bearing uses, such as interior decoration and furniture components. The findings underscore the dual benefits of this approach: reducing greenhouse gas emissions and landfill dependency while lowering waste management costs. By integrating circular economy principles, this research demonstrates the feasibility of upcycling leaf waste into innovative products, providing both environmental and socio-economic value.

Conditional Optimization for Treatment of Wastewater from Ethanol Production Process Using Ozonation

Wed, 24 Dec 2025 00:00:00 +0700

This study aimed to determine the optimal conditions for removing COD and color from ethanol production effluent using the ozonation process. The investigation employed Response Surface Methodology (RSM) with a Central Composite Design (CCD) model, focusing on two key variables: ozone dosage rate (900, 1,200, and 1,500 mg/hr) and contact time (60, 90, and 120 minutes). The results showed that the highest COD and color removal efficiencies—63.32±1.28% and 75.65±1.42%, respectively—were achieved at an ozone dosage of 1,500 mg/hr and a contact time of 120 minutes. Based on the ANOVA statistical analysis of the treatment results, the Quadratic Model and the Linear Model were found to be suitable for describing the relationship between the variables (ozone dosage rate and contact time) and the COD and color removal efficiencies of effluent from a UASB tank, which is the wastewater after preliminary treatment, using the ozonation process. According to the model, the optimal conditions for maximum treatment efficiency were an ozone dosage rate of 1,500 mg/hr and a contact time of 116.881 minutes, which predicted COD and color removal efficiencies of 63.99% and 75.79%, respectively. To validate these findings, a series of experiments was conducted under the recommended optimal conditions. The average COD removal efficiency observed was 62.99±0.68%, which closely aligns with the model prediction, with a deviation of only 1.60%. Similarly, the average color removal efficiency was 73.22±0.62%, showing a minor deviation of 3.51% from the predicted value. These results confirm the reliability and suitability of the CCD model in optimizing the ozonation process for treating effluent from ethanol production.

People’s Perception and Water Consumption Behavior in High Fluoride Risk Area

Patcharaporn Somkiattiyot, Aunnop Wongrueng, Sarunnoud Phuphisith — Wed, 24 Dec 2025 00:00:00 +0700

Fluoride contamination in groundwater remains a persistent environmental and public health challenge in northern Thailand, where natural geological formations contribute to elevated fluoride concentrations. This study aimed to assess residents’ awareness of fluoride-related risks, drinking water practices, and acceptance of defluoridation technologies in high-fluoride areas of San Kamphaeng District, Chiang Mai Province. A total of 205 residents were interviewed using a structured questionnaire. The results showed that bottled water was the most commonly used for household water consumption, accounting for 66.9% for drinking and 42.3% for cooking. However, some households in high-fluoride villages still relied on untreated groundwater, with drinking and cooking accounting for up to 4.2% and 14.3% of total daily water use, respectively. Although 92.7% indicated strong support for a community defluoridation system, most respondents demonstrated limited knowledge of fluoride contamination and its health implications. No significant effects of gender or age were observed regarding knowledge, perceived risk, perception of groundwater use, or the desire for defluoridation system. These findings underscore the need for strengthened public education and community-based communication strategies to promote safer water consumption and support long-term access to safe drinking water.

Application of Submerged Nanofiltration Membrane for Treating Natural Organic Matter from Reservoir Water

Chamaiporn Nantakham, Takahiro Fujioka, Aunnop Wongrueng, Prattakorn Sittisom — Wed, 24 Dec 2025 00:00:00 +0700

Surface water quality continues to be compromised by expanding residential and industrial activities. Chlorine is widely used in conventional treatment systems due to its low cost and availability; however, its reaction with natural organic matter (NOM) generates disinfection by-products (DBPs), particularly trihalomethanes, which are known as human carcinogens. Despite the increasing interest in nanofiltration (NF) membranes, studies on the application of submerged NF systems for treating real surface water without pretreatment remain limited, especially regarding trihalomethane precursor removal, ion rejection, and permeate stability. Comparative data with conventional treatment systems is also insufficient. This study investigates the performance of a submerged NF membrane relative to a conventional treatment system in a previous study for NOM removal. Water samples were collected every three days from Ang Kaew Reservoir, and the NF system was operated at a constant flux of 11 L/m²·h. All samples were analyzed at the Environmental Engineering Laboratory, Chiang Mai University. The NF membrane achieved significant reductions in turbidity (93-98%), electrical conductivity and total dissolved solids (36-65%), UV254 (74-89%), dissolved organic carbon (68-80%), and trihalomethane formation potential (66.54%). In contrast, the conventional system exhibited limited ion removal and, in some cases, increased ion concentrations. These results indicate that submerged NF membranes offer superior ion rejection and effective control of DBP precursors, demonstrating their potential for producing high-quality drinking water from surface water under stable operating conditions.

Assessment of Greenhouse Gas Emission Reduction Potential from Decentralized Community-Based Solid Waste Management: A Case Study in Ban Non Sung, Sisaket, Thailand

Wed, 24 Dec 2025 00:00:00 +0700

Greenhouse gas (GHG) emissions from municipal solid waste (MSW) significantly contribute to climate change, particularly through methane (CH₄) and carbon dioxide (CO₂) emissions from landfills. This study evaluates the potential for GHG emissions reduction through improved solid waste management practices in Ban Non Sung, Khun Han district, Sisaket province, Thailand. Data was collected for 1 fiscal year, covering 1,586 residents across 340 households. Waste segregation at source included composting, bio-fermentation, animal feed conversion, and recycling. GHG emissions reductions were calculated based on national methodologies. Results showed that 69.27% of sorted waste was organic, with per capita sorted waste generation of 0.07 kg/day. The total estimated GHG emissions reduction was 41,111.78 kg CO₂eq/year (0.96 kg CO₂eq per kg sorted waste). Animal feed conversion was the most effective method, contributing 40.89% of the total reduction, primarily due to the dual benefit of methane avoidance and commercial feed displacement. Additionally, secondary national data from the Pollution Control Department (PCD) for 2020–2023 indicated a steady increase in source-sorted waste and corresponding GHG reductions, emphasizing the role of community-based waste initiatives in meeting national climate goals. The findings support the integration of sustainable waste practices to significantly mitigate GHG emissions in large communities.