Orathai Chavalparit

Optimizing electrocoagulation process for the treatment of biodiesel wastewater using response surface methodology.

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.

Commuter exposure to BTEX in public transportation modes in Bangkok, Thailand

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.

Anaerobic baffled reactor treatment of biodiesel-processing wastewater with high strength of methanol and glycerol: reactor performance and biogas production

Biodiesel-processing factories employing the alkali-catalyzed transesterification process generate a large amount of wastewater containing high amount of methanol, glycerol, and oil. As such, wastewater has high potential to produce biogas using anaerobic treatment. The aim of this research was to investigate the performance of an anaerobic baffled reactor for organic removal and biogas production from biodiesel wastewater. The effect of different organic loading rates, varying from 0.5 kg m−3 d−1 to 3.0 kg m−3 d−1 of chemical oxygen demand, was determined using three 22 L reactors, each comprising five separate compartments. Wastewater was pretreated with chemical coagulants to partially remove oil prior to experimentation. Results show that the anaerobic baffled reactor operated at 1.5 kg m−3 d−1 of chemical oxygen demand and ten days of hydraulic retention time provided the best removal efficiencies of 99 % of chemical oxygen demand, 100 % of methanol, and 100 % of glycerol. Increasing the organic loading rate over 1.5 kg m−3 d−1 of chemical oxygen demand led to excessive accumulation of volatile fatty acids thereby making the pH drop to a value unfavorable for methanogenesis. The biogas production rate was 12 L d−1 and the methane composition accounted for 64–74 %. Phase-separated characteristics revealed that the highest chemical oxygen demand removal percentage was achieved in the first compartment and the removal efficiency gradually decreased longitudinally. A scanning electron microscopic study indicated that the most predominant group of microorganisms residing on the external surface of the granular sludge was Methanosarcina.

Development of environmental sustainability for the biodiesel industry in Thailand

The Thai Government has committed to promoting the production and use of biodiesel in place of petro-diesel oil, with the objective of reducing the countrys dependence on imported oil. However, biodiesel production generates large amounts of waste and wastewater. This research aspires to adopt industrial ecology measures to alleviate environmental problems encountered in the biodiesel industry in Thailand. The proposed implementation options included clean technology and waste exchange measures. Five biodiesel production factories were selected to analyse material flow and balance in the production processes. The results show that 1 m3 biodiesel production generated 8 kg of spent bleaching earth, 140 kg of glycerine and 0.50 m3 of wastewater with a chemical oxygen demand (COD) content of up to 170,000 mg/L. The postulated options, on the basis of clean technology, included methanol recovery from the methyl ester and glycerine mixture, substitution of the hydroxide catalyst by methoxide, and reuse of the final washing water used in the methyl ester purification step. These options are expected to reduce raw material and water use in the production processes. The wastes or by-products generated from the biodiesel production process can be utilised as raw material for other industries. Crude glycerine, which is produced in large quantities from the trans-esterification process, can be reused or recycled by a value-added conversion for other industries. In addition, the biodiesel wastewater mostly obtained from the methyl ester washing process can be treated in an anaerobic digestion system to produce biogas for electricity generation.

Biogas Production from Napier Grass (Pak Chong 1) (Pennisetum purpureum × Pennisetum americanum)

The objective of this research was to evaluate the quantity of biogas production from napier grass (Pak Chong 1) (Pennisetum purpureum × Pennisetum americanum) in three identical continuously stirred tank reactor (CSTRs) at room temperature. The volatile solids feed was varied at 1.5, 2 and 3%, respectively. The organic loading rate was altered at 0.43, 0.57 and 0.86 kg VS/m3.d in CSTR 1, 2 and 3, respectively. Three laboratory scale CSTRs with working volume of 5 l were carried out. The results showed that the optimum volatile solids fraction was 2% VS with maximum biogas production of 0.529 m3/kg VS added. The methane production was achieved at 0.242 m3/kg VS added. Under this condition, the soluble chemical oxygen demand (SCOD) of the hydrolysate was increased by 74% and the SCOD and VS removal efficiency were obtained 52.52% and 55.98%, respectively. The highest total volatile fatty acid was obtained on day 12, which was 5.51 g/l and the highest concentration of HAc was 4.33 g/l. The results indicated that volatile solids fraction was 2% VS achieves a maximum biogas yield and can be successfully converted using anaerobic digestion and was investigated into economical and scalable.

Development of sustainable waste management toward zero landfill waste for the petrochemical industry in Thailand using a comprehensive 3R methodology: A case study.

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.

Evaluation of greenhouse gas emissions and reduction from the petrochemical industry in Thailand

This study aims to determine the baseline and indicators for greenhouse gas (GHG) emissions and to evaluate the effectiveness of mitigation measures used to reduce GHG emissions in Thai petrochemical plants. The results demonstrate that petrochemical production between 2005 and 2010 had an annual energy requirement in the range of 120,000–170,000 TJ. The proportions of energy consumption for the petrochemical industrys upstream, intermediate and downstream groups were 75%, 14% and 11%, respectively. The amount of GHG emissions from the petrochemical industry during 2005–2010 was approximately 8000 to 12,000 kt CO2 eq./year. This value represents approximately 3% of the total GHG emissions of Thailand. The upstream petrochemical industry accounted for the highest GHG emissions of 62%, whereas the intermediate and downstream groups were responsible for 21% and 17%, respectively. The carbon intensities of the upstream petrochemical products for the olefin and aromatic groups ranged from 1.104 to 1.485 t CO2 eq./t and 0.420 to 1.125 t CO2 eq./t, respectively. For the intermediate and downstream petrochemical products, the carbon intensities ranged from 0.396 to 1.209 t CO2 eq./t and from 0.096 to 0.477, respectively. The likely reason for the decrease in carbon intensity from 2005 to 2010 is that the industry sector implemented measures to improve energy conservation and updated production processes. The most significant potential for GHG emissions reduction was found in fuel conservation measures, steam conservation measures and electricity conservation measures.

Evaluation of the environmental impact of portion bag for food packaging: a case study of Thailand

This study applied life cycle assessment methodology in evaluating environmental impact of portion bag. The objective of this study was to identify the hotspot of environmental impact through life cycle of portion bag. The options were proposed for improving environmental performance of the product. The system boundary was defined as cradle-to-grave which included the ethylene production, LDPE and LLDPE resins production, portion bag production, disposal, and transportation. All materials and emissions were calculated based on 1 piece of portion bag which weighed 2.49 g. IMPACT 2002+ was used for assessing environmental impact on SimaPro V8.2 software. The result found that the most of environmental impact was generated from LDPE and LLDPE resins which was used as raw material for producing portion bag. After normalization, non-renewable energy showed the highest potential to concern. This impact related directly to the natural gas drilling, ethane production, ethylene production, resin productions, and energy in all process. In conclusion, it should be suggested that the selection of bio-material for producing portion bag can play an important role to reduce the environmental impact. The research demonstrates the possible way and benefits in improving cleaner raw material and suitable way of products end-of-life for producing green portion bag in the future.

Enhancing Biogas Production from Sugarcane Bagasse Using Steam Explosion in According With Acetic Acid Pretreatment

Dilute acetic acid was used to pretreat sugarcane bagasse with 180°C steam explosion prior to anaerobic digestion. The Central Composite Design (CCD) was employed to recognize the optimum condition of pre-treatment sugarcane bagasse for biogas production. The individual variable effects of acetic acid concentration and reaction time on enhancing biogas production were investigated using response surface methodology (RSM). Data obtained from RSM analysis on biogas production were depending on analysis of variance (ANOVA). After optimization, the optimum pre-treatment condition was at 1.0% acetic, 17.45 min reaction time, while the maximum biogas production (434.47 L/kgVS) was 91.88% higher than the control (226.42 L/kgVS). Hence the optimum pre-treatment conditions for maximum biogas production were obtained by RSM analysis. It can be concluded that dilute acetic acid and steam explosion techniques can be used to achieve higher biogas.

Scenarios of Municipal Solid Waste Management for Mitigating Greenhouse Gas Emission: A Case Study of Supermarket in Bangkok, Thailand

As a consequence of rapid urbanization and population growth, many cities have faces issues of waste management. Landfill approach is generally decided for handling most of municipal solid waste, resulting the impacts of environment especially land occupation and global warming. As commercial building plays an importance role not only for economic value but also for environmental aspects, a supermarket located in community mall was selected as a case study towards sustainable cities. This study was aimed to investigate the current MSW management system of supermarket in order to quantify its environmental performance and to propose suitable options for improving municipal solid waste management. The findings revealed that at the business-as-usual, 397 tCO2e was emitted annually from landfilling waste of a supermarket in Thailand. However, if waste management has improved by recycling plus bio-gasification approach, not only 374 tCO2e/year will not be emitted from landfilling, but 243 tCO2e/year also be reduced due to the activities in relevant to recycling and bio-gasification process. Moreover, applying such approach provides benefit in economic term about 18,321 USD a year. The results of this study could inspire another commercial buildings or others sector to adopting waste management practices together for creating a network of sustainable cities through suitable waste management system.