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Napier grass is a potent source of biomass commonly grown throughout the tropics. Here the effects of harvesting age and performance evaluation on Napier grass biogasification were investigated. Three different harvesting ages of fresh Pakchong-1 Napier grass at 35, 45, and 55 days were digested. Two separated stages process, combining Completely Stirred Tank Reactor (CSTR) and Anaerobic Baffle Reactor (ABR), was then operated for acidification and methanation. The results depicted that the different grass harvesting ages promoted different characteristics of biomass feedstock in particular for total solid, lignin content, and C/N ratio. The different gases production potentials about 70.8-164.6 ml biogas/g VS and 32.9-84.5 ml CH/g VS were then promoted. The acidification of 45 days harvesting age at 1.5-3.0% (VS) in CSTR generated the different acid production for 5.9-7.5 g/l. The selected solid load of 2.0% VS generated about 21.1 g COD/l or 7.5 g TVA/g VS. This was solubilized for almost 50% and consisted of acetic acid for 77.2-82.2%. The gases production from this hydrolysate in ABR was stably operated and produced about 484.0 and 267.8 ml /g COD for biogas and methane, respectively. This result depicted the possibility of biogas production from Pakchong-1 Napier grass employing two separated stages process. [ABSTRACT FROM AUTHOR]

This paper is aimed to systematically assess greenhouse gases (GHGs) and energy intensity of the granite rock mining operations in Thailand and also identify a range of feasible options to minimize their GHG emissions. Mining factories A, B and C, located in the Eastern region of Thailand, were selected as research case studies. The results indicated that the 3-year average of GHGs emissions from factories A to C was 3387 718 kgCO2e per year with approximately 2.92 kgCO2e per ton of granite rock produced over 2012 to 2014. Of this, the carbon intensity of grid-electricity consumption for the crushed rock production was 1.84 kgCO2/kWh. Diesel fuel combustion for transport activities in the mining factories was the greatest contributor to GHGs emissions (68 %) compared to the purchased electricity and explosion process, with 31 % and 1 %, respectively. In-Pit Crushing and Conveying (IPCC) installation, haul truck payload optimization and management, and reduction in tire rolling resistance have shown potential to reduce carbon emissions accounted for 20 % to 70 %.

Environmental impacts from natural gas power plant in Thailand was investigated in this study. The objective was to identify the hotspot of environmental impact from electricity production and the allocation of emissions from power plant was studied. All stressors to environment were collected for annual natural gas power plant operation. The allocation of environmental load between electricity and steam was done by WRI/WBCSD method. Based on the annual power plant operation, the highest of environmental impact was fuel combustion, followed by natural gas extraction, and chemical reagent. After allocation, the result found that 1 kWh of electricity generated 0.425 kgCO2eq and 1 ton of steam generated 225 kgCO2eq. When compared based on 1GJ of energy product, the result showed that the environmental impact of electricity is higher than steam product. To improve the environmental performance, it should be focused on the fuel combustion, for example, increasing the efficiency of gas turbine, and using low sulphur content of natural gas. This result can be used as guideline for stakeholder who engage with the environmental impact from power plant; furthermore, it can be useful for policy maker to understand the allocation method between electricity and steam products.

The objectives of this study were to estimate energy and carbon intensities of natural gas combined-cycle power plants and to improve the energy efficiency of power plants through an exergy analysis. Three plants in Thailand were evaluated as case studies in this research using data collected in 2013 – 2014. The results showed that the average carbon and energy intensities of three Combined-Cycle Power Plants were 0.436 kg CO2/kWh and 7.995 GJ/MWh, respectively. The range of the energy intensity in this study was slightly lower than that of other studies; however, the results of the carbon intensity were in the same range. The result of the exergy analysis illustrated that Heat Recovery Steam generator (HRSG) has the greatest exergy destruction due to the wide temperature range. To summarize, natural gas combined-cycle power plants require less energy and emit less carbon compared to other technologies or fuels. The exergy efficiency of HRSG was 60%, with an exergy destruction rate of 66.88 MW. One approach to improve the efficiency of power plants is to improve the efficiency and performance of HRSG.

This research is aimed to estimate energy consumption and the greenhouse gases emission from olefins production process in Thailand and to analysis its correlation between energy intensity and carbon intensity. The results of five olefin case study plants showed that direct energy use of olefins production was about 87% of total energy consumption. The greatest amount of energy demand was supplied for fuel combustion in manufacturing processes. The olefin plants using gas feedstock could operate with less amount of energy consumed as the average energy intensity (EI) of 23.88 GJ/ton of olefin produced, whereas plants of olefin produced from steam cracking of liquid feedstock had the average EI of 33.21 GJ/ton of olefin produced. Greenhouse gas emission from olefin plants using gas feedstock were consistent with the result of EI. The carbon intensity (CI) from olefin plants using gas feedstock (0.98 tCO2-eq./ton of olefin produced) was lower than the plants using liquid feedstock (2.01 tCO2-eq./ton of olefin produced). The T-test function used to reflect the correlation between EI and CI emphasized that the carbon intensity was significantly correlated with the intensity of energy (r = 0.9564 and p = 0.05).

Two constructed wetlands were evaluated regarding their performance in treating different wastewaters under the tropical conditions of Thailand. The first one was for treating the domestic sewage from a governmental institute, whereas the latter was used to improve the quality of the effluent from a central aerated lagoon, for which the influent had been already pretreated by about 100 factories in an industrial estate. The hydraulic loading rate and the hydraulic retention time were 0.015 m3/m2-d and 28 days and 0.3 m3/m2-d and 3 days for the two wetland systems, respectively. The physical and chemical water quality and the occurrences of protozoa and metazoa were monitored for three seasons, each of which had samples taken twice a week for two months. The temperature wasquite constant throughout the whole year, ic., 26 to 31 deg.C and 25to 34 deg.C for the two wetlands, respectively. The water quality ofthe wetland effluents was rather good; the BOD and TKN were only 4.5and 3.3 mg/l and 2.7 and 6.8 mg/l for the two cases. A relationship between the filtered BOD and the zoological characteristics was established. As a result, a simple glance at the occurrence of certain metazoa and protozoa can rapidly but approximately predict the water quality of the system. (c) 1997 IAWQ. Published by Elsevier Science Ltd. [ABSTRACT FROM AUTHOR]

This study evaluates the greenhouse gas (GHG) emissions and economic value creation of plastic waste (PW) management in Rayong, Thailand, a city on the eastern Gulf Coast with a significant amount of generated and leaked PW. By analyzing current practices, and developing and evaluating improvement scenarios, the study explores strategies for reducing GHG and enhancing economic benefits across the PW management chain. Four primary routes with varying capacities handle approximately 5,445.55 tonnes of PW via source separation recycling (5.18 %), post-sorting recycling (9.30 %), energy recovery (54.86 %), and landfills or opened dump disposal (30.66 %). About 83.21 % of the 16 ± 6.9 % PW in municipal solid waste (MSW) is recyclable, primarily consisting of high-density polyethylene (HDPE), polypropylene (PP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polyethylene terephthalate (PET). The current management practice generates an economic benefit of approximately 1.68 million USD/yr or 310 USD/t of PW, compared to the proposed scenarios, which enhances recycling efficiency and reduces landfill and energy recovery waste, yielding 2.27-6.48 million USD/yr or 420.64-1200.33 USD/t of PW. The practice emits about 7,028.47 tCO 2 e annually, while improved source and post-sorting efficiencies reduce GHG emissions by 2.86-3.17 times or -2.83 to -2.42 tCO 2 e/t of PW or a total of over 13,078.60-15,268.44 tCO 2 e. Burning PW increases approximately 1.6 times or 11,841.36 tCO 2 e/yr. Enhancing recycling efficiency, particularly through source separation, is key to promoting more productive and valuable PW separation, increasing economic value and GHG mitigation by approximately 3.87 and 3.17 times, respectively. These findings provide valuable insights for local authorities and policymakers to develop strategic interventions and policies that align with the improved scenario by enhancing source separation and recycling. The results demonstrate that improving the efficiency of separation at the source is critical for transitioning from a linear PW management strategy to a circular economy, significantly reducing landfill waste and mitigating environmental threats., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Sutisa Samitthiwetcharong reports financial support was provided by 10.13039/501100004704National Research Council of Thailand. Orathai Chavalparit reports financial support was provided by 10.13039/501100017170Thailand Science Research and Innovation Fund 10.13039/501100002873Chulalongkorn University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The transition to net-zero emissions (NZEs) in developing countries is challenging and requires the immediate adoption of comprehensive climate policy packages, strong collaboration among all sectors and stakeholders, and timely financial and technological assistance for developing economies. This research aims to analyze and evaluate the pathways to realize an NZE scheme at the municipality level. Nakhon Ratchasima (NR) Municipality, Thailand, is selected as the case study for this research. The Global Protocol for Community-Scale GHG Emission Inventories (GPC) is applied as the robust framework to assess the city's GHG emission profile. A mathematical forecasting model and the participatory multicriteria decision-making (MCDM) approach were adopted to support evidence-based local climate action planning based on four different scenarios: the business-as-usual (BAU), nationally determined contribution (NDC), carbon neutrality (CN), and NZE scenarios. The roles of stakeholders at the local community level across all sectors in mitigation actions and investment costs were investigated, and cost-effectiveness was evaluated to understand the economic performance of the adoption and implementation of local climate policy packages. The results indicate that by employing solely conventional technologies, a residential city that is also a hub for trade and land transportation will be unable to achieve its net-zero targets. It is imperative to seek additional low-carbon businesses and decarbonizing technologies that accompany substantial investments. According to the case of NR Municipality, the implementation costs to attain the NZE target by 2050 would range between 974.40 and 4.131.96 million USD. A pivotal driver of the municipal NZE pathway is the successful mobilization private sector investments to propel the transition toward climate-friendly technologies. Cost-effectiveness analysis significantly bolsters the municipality's transitional plan preparation, holistically encompassing economic, social, and environmental considerations. By preparing these aspects together, we ensure a smooth and equitable transition to net zero, avoid conflicts and economic harm and leave no one behind. This approach ensures a harmonious balance between a net-zero future, economic growth, and environmentally friendly living for all., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Athitinon Phupadtong reports financial support was provided by Chulalongkorn University., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Air pollution, owing to the ever-increasing transport vehicle fleet, and adverse health effects are increasing in provinces of Thailand. The study estimated that the vehicle fleet size of Nakhon Ratchasima (NR) province of Thailand will grow to 2 million vehicles by 2030, which was 1.36 million in 2021. In NR, the PM 2.5 and PM 10 concentrations already surpassed both WHO and NAAQS guidelines in 2019-2021. Using Pollution Control Department (PCD) approved Tier I and II Methodology of EMEP/EEA, this research estimated that the total tailpipe emission load will be 1039 tons of PM 2.5 , 16,630 tons of NO₂, 20,623 tons of CO, 195 tons NH₃, and 249 tons of SO₂ in NR during 2030. The emission load will increase to 1752 tons of PM 2.5 , 21,126 tons of NO 2 , 25,559 tons of CO, 361 tons of NH 3 and 9344 tons of SO₂ during 2030 if upstream emissions are considered. This study has developed five control scenarios in line with the directives of PCD to mitigate the adverse health from vehicle-led air pollution in NR and implementation during 2024-2030. According to the study, different control scenarios to be implemented during 2024-2030, will be able to keep the fleet size of vehicles in the NR under control. The results show that the control scenarios will keep the annual tailpipe emission of PM 2.5 at 604 tons in 2030, a 42 % reduction over the 2030 Business-As-Usual scenario (BAU). The health damage in the range of 6941 to 11,625 disability-adjusted life years (DALYs) under the 2030 BAU scenario in NR due to tailpipe and upstream emissions can be reduced to 4162-7318 DALYs with the implementation of different control scenarios. The control scenarios will also provide significant economic benefits ranging from 4465 to 6718 million THB during 2024-2030 through reduced DALYs and associated costs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The circularity of plastic packaging waste (PPW) material via recycling is critical to its circular economy towards sustainability and carbon neutrality of society. The multi-stakeholders and complex waste recycling loop of Rayong Province, Thailand, is herein analysed using an actor-network theory to identify key actors, roles, and responsibilities in the recycling scheme. The results depict the relative function of three-actor networks, namely policy, economy, and societal networks, which play different roles in PPW handling from its generation through various separations from municipal solid wastes to recycling. The policy network comprises mainly national authorities and committees responsible for targeting and policymaking for local implementation, while economic networks are formal and informal actors acting for PPW collection with a recycling contribution of 11.3-64.1%. A societal network supports this collaboration for knowledge, technology, or funds. Two waste recycling models are classified as community-based and municipality-based management, which functions differently by coverage areas, capabilities, and process efficiency. The economic reliability of each informal sorting activity is a crucial factor for sustainability, while empowering people in environmental awareness and sorting ability at the household level is also essential, as well as law enforcement that is effective in the long-term circularity of the PPW economy., (© The Author(s), under exclusive licence to Springer Nature Japan KK, part of Springer Nature 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Sustainable waste management was introduced more than ten years ago, but it has not yet been applied to the Thai petrochemical industry. Therefore, under the philosophy of sustainable waste management, this research aims to apply the reduce, reuse, and recycle (3R) concept at the petrochemical factory level to achieve a more sustainable industrial solid waste management system. Three olefin plants in Thailand were surveyed for the case study. The sources and types of waste and existing waste management options were identified. The results indicate that there are four sources of waste generation: (1) production, (2) maintenance, (3) waste treatment, and (4) waste packaging, which correspond to 45.18%, 36.71%, 9.73%, and 8.37% of the waste generated, respectively. From the survey, 59 different types of industrial wastes were generated from the different factory activities. The proposed 3R options could reduce the amount of landfill waste to 79.01% of the amount produced during the survey period; this reduction would occur over a period of 2 years and would result in reduced disposal costs and reduced consumption of natural resources. This study could be used as an example of an improved waste management system in the petrochemical industry., (© The Author(s) 2014.)

Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in four public transportation modes in Bangkok, Thailand during two rush hour periods (7:00-9:00 a.m. and 4:00-7:00 p.m.). The four modes included an air-conditioned bus (A/C bus), non-air-conditioned bus (non-A/C bus), electric sky train, and a passenger boat traveling along the canal. Comparison among three important bus routes was also studied. In-vehicle air samples were collected using charcoal sorbent tubes and then analyzed by a gas chromatography-mass spectrometer. Results showed that the transportation modes significantly influenced the abundance of in-vehicle benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). Median concentrations of BTEX were 11.7, 103, 11.7, and 42.8 microg/m3 in A/C bus; 37.1, 174, 14.7, and 55.4 microg/m3 in non-A/C bus; 2.0, 36.9, 0.5, and 0.5 Cig/m3 in sky train; and 3.1, 58.5, 0.5, and 6.2 microg/m3 in boat, respectively. Wilcoxon rank sum test indicated that toluene and m,p-xylene in the sky trains were statistically lower than that in the other three modes at a p-value of 0.05. There were statistical differences in TEX concentrations among the bus routes in the non-A/C buses. In addition, the benzene to toluene ratios implied that tail-pipe emissions were important contributor to the abundance of in-vehicle VOCs.

The production of biodiesel through a transesterification method produces a large amount of wastewater that contains high levels of chemical oxygen demand (COD) and oil and grease (O&G). Currently, flotation is the conventional primary treatment for O&G removal prior to biological treatments. In this study, electrocoagulation (EC) was adopted to treat the biodiesel wastewater. The effects of initial pH, applied voltage, and reaction time on the EC process for the removal of COD, O&G, and suspended solids (SS) were investigated using one factor at a time experiment. Furthermore, the Box-Behnken design, an experimental design for response surface methodology (RSM), was used to create a set of 15 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the pollutant removals. The experimental results show that EC could effectively reduce COD, O&G, and SS by 55.43%, 98.42%, and 96.59%, respectively, at the optimum conditions of pH 6.06, applied voltage 18.2 V, and reaction time 23.5 min. The experimental observations were in reasonable agreement with the modeled values.