Advanced Materials Research Vols. 931-932

Abstract: The objective of this study was to determine the effect of adding biomass fly ash to co-composting of tree pruning waste and cow dung. Shredded tree pruning waste and cow dung were used as compost mix. Biomass fly ash was added to achieve the following proportions: 0% (control), 4%, 8% and 12% (wt/wt). The mixtures, turned once a week, were composted in 120-L perforated polyethylene bins for 150 days. The temperature in the middle of the waste layer in each bin was recorded daily, and averaged 32.1-33.3°C. Compost was taken randomly from each bin once a week during turning and its characteristics analysed. The pH of the compost mixes gradually increased from 6.96-8.41 to 8.51-8.95. The EC of the compost mixes increased from 0.69-0.88 dS/cm to 0.97-1.21 dS/cm. The C/N ratio of the compost mixes decreased continuously from around 30 to stability at 12.96-14.04. The volatile solids of the compost mixes decreased continuously from 79.8-87.8% to stability at 55.4-68.5%. The initial NH₃-N and NO₃-N in the compost mixes were 9.1-11.5 and 1.75-3.03 mg/kg, respectively. The NH₃-N contents decreased to 5.41-7.31 mg/kg, while the NO₃-N increased to 6.45-7.84 mg/kg. We investigated more than half of the organic portion of each compost mix. Adding fly ash up to 12% (wt/wt) did not affect the composting process or resulting compost, and there was no indication that its high pH increased ammonia volatilization during composting.

Abstract: This research aims to produce activated carbon from bamboo waste (used bamboo chopsticks), activated by low-cost and non-toxic chemical substance (Sodium Chloride, NaCl), as an option for silk dyeing wastewater treatment in a small cottage industry. Initially, used bamboo chopsticks were carbonization at 600 °C to produce bamboo charcoal. Then the charcoal was activated using three different methods: (a) soaking in the NaCl solution at the charcoal to NaCl (weight/weight) ratio of 1:1; (b) burning at 800 °C; and (c) activating using the previously mentioned 2 methods together by soaking in the NaCl solution at the ratio of 1:1 then burning at 800 °C. The activated carbons physical characteristics study has found that the activated carbon activated using the third method had the highest BET specific surface area of 327.69 m²/g, total specific pore volume of 0.18 mg/l, and average pore size of 22.52 Å. The adsorption study of the activated carbon activated by NaCl and temperature used synthetic wastewater of red acid dye (AR114) with the initial concentrations of 20 mg/l. The study results have showed that the activated carbon activated by NaCl and temperature reached equilibrium within 180 minutes, and had the color removal efficiency of 77.36%. The adsorption isotherm study results have indicated that the acid dye adsorption of the activated carbon activated by NaCl and temperature followed the Langmuir isotherm.

Abstract: The municipal solid waste management (MSWM) is one major concern in Cambodia due to complicated problems from waste sector. Until now, because of poor MSWM, solid wastes have produced high pollution, like methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2), which are the substances of greenhouse gas affect to climate change. Therefore, this study was undertaken to estimate and compare the greenhouse gas (GHG) emission from municipal solid waste in different cities namely; Phnom Penh, Battambang, and Siem Reap of Cambodia. GHG emission was calculated through Intergovernmental Panel on Climate Change (IPCC) calculator 2006 based on secondary data of 2009 for all cities. In order to reduce the GHG emission, four scenarios were proposed with different waste treatment technologies such as composting, anaerobic digestion, waste reduction at landfill by separating waste for recycling before disposal off in landfill, and landfill with gas recovery as well. Additionally, the multiple benefits of implementing the proposed scenarios may include reduction of GHG emission, promotion of energy saving for landfill operation, and promotion of the renewable energy concept like electricity.

Abstract: Hydrogen sulfide (H₂S) isclassified as toxic gases that are commonly known to be generated from an anaerobic process, volcanic explosion and petroleum related processes. Low concentration of H₂S causes irritation on human eyes and respiratory system as well as nuisance problem due to its rotten-egg smell. Insanitary dumpsite of municipal wastes containing high organic fraction could be a source of H₂S emission, which affects the quality of life of nearby communities. This study assessed the H₂S dispersion from dumpsite in Nakhon Si Thammarat using the source dispersion model, AERMOD. Emission rate of H₂S generated at dumpsite was estimated using emission factor of 1.76 mg.m^-2.d^-1 taken from AP-42 (USEPA.). For meteorological data, hourly average data in 2012 were collected from three meteorological stations which were Nakhon Si Thammarat, Surat Thani and Trang Provinces. Meteorological data were primarily utilized from Nakhon Si Thammarat. Only missing values were filled by the data from Surat Thani and Trang, respectively. Results revealed that maximum concentrations of H₂S in 2012 were 0.595, 0.066 and 0.058 ppb, respectively for 1 hour average (1^st highest), 24 hour average (1^st highest) and annual average over the study area of 10 km x 10 km surrounding the source. Maximum concentration of H₂S emitted from dumpsite was mainly confined within 1.5 km surrounding the sources, particularly to the east and northeast area. The simulated concentrations of H₂S did not exceed the suggested standard values; however, the 1^st highest hourly average concentration was reached the odor threshold (0.5 ppb). To clarify the simulated H₂S concentrations, further works should be included the field sampling of H₂S at dumpsite to obtain the actual emission rate. Meteorological data in several years should be also used to provide the concrete pattern of H₂S dispersion.

Abstract: This study is aimed to determine the emission of oxide of nitrogen (NO_x), released from combustion of LPG, used in households cooking. The emission factor and emission inventory of NO_X for the household activity are developed taking into consideration local characteristic of the household in Thailand. Activities data in this study are collected in Rayong province. These data will serve and assist in developing the emission database under the Pollutant Release and Transfer Registration (PRTR) program. Emission factors of NO_x, based on amount of LPG usage per household per year are calculated for different size of household. These values are 142.2, 213.3 and 426.6 kg of NO_x /1000 household/year for small, medium and large sizes of household, respectively. It is estimated that the total amount of NO_x emissions from households LPG cooking will be about 60.31 tons per year in Rayong province.

Abstract: Laboratory is one of non-point source, which use chemical substance for an experimental analysis and which may release chemical into an environment. There is a lack of information about the release of chemical to the environment from laboratory activity. In this study, releasing of volatile organic compound from school, university and commercial laboratories are estimated. Direct measurement of target chemical concentrations in laboratory are taking into account the normal practice in each laboratory. Emission factors of ethyl acetate are calculated as 383.09, 174.13 and 445.53 kg (release to air) per 1000 kg of amount of usage for school laboratory (opened room), school laboratory (closed room) and university laboratory, respectively. Results of this study indicated that emission rate of VOCs from chemical laboratory will be dramatically decreased as a result of installation of VOCs treatment.

Abstract: The objective of this study was to determine formaldehyde emission considering the following factors; indoor air temperature, type of resin, and thickness of particleboard. Formaldehyde emissions from particleboards were analyzed using the JIS A 1460 and the Perforatored EN 120 methods. Three sets of experiments were conducted to investigate effects on formaldehyde emission from particleboard samples due to these factors. For the first factor, test specimens were conditioned in a dry oven at 20, 35, and 40 °C for a period of 1, 2, 3, 5, and 7 days, emission were analyzed using the JIS A 1460 method. The second factor, type of resin, formaldehyde emissions and remaining were analyzed by the JIS A 1469 and the Perforatored EN 120 methods. For the third factor, thickness of particle board, samples with different thickness were used in the experiments. Results of the first factor indicated that the highest formaldehyde emission was obtained at the condition temperature of 20 °C followed by the emissions at the condition temperature of 35 °C and 40 °C, respectively. In addition, formaldehyde emissions decreased as the condition time increased. Results of the second factor showed that for the JIS A 1469 method, particleboards made with the 10L617A (UF:E1) resin emitted the lowest amount of formaldehyde. While particleboards made with the 10L631 (MUF:E2) resin emitted the lower amount of formaldehyde as compared to the particleboards made with the 10L686 (UF:E2) resin. For the Perforatored EN 120 method, formaldehyde remaining in samples made with UF:E0 was lowest followed by samples made with UF:E1 and UF:E2, respectively. Results for the third factor indicated that the thickness of particleboard has no significant effect on formaldehyde emission. This effect was found for both methods of analysis.

Abstract: The annual arithmetic mean concentrations of benzene and 1, 3-butadiene were gradually decreasing tendency from the year 2008 2011 at every monitoring stations in Bangkok. Dramatically decreasing of these air toxics, measured in the road curbside areas were found in the year 2012 when the Thais government implemented the improvement of fuel quality from Euro 2 to Euro 4 standards. Calculated cancer risk of benzene and 1, 3-butadiene dramatically decreased at every monitoring stations. The results indicated that the population was estimated to receive an excess lifetime cancer risk greater than 1 x 10^-5, which is proposed as the permissible maximum value for individual excess lifetime cancer risk by the Japan Environmental Agency (JEA). However, cancer risk from air toxic was found significantly decreased in the year 2012. These finding elucidated the effectiveness of changing of fuel quality to the reduction of airborne air toxic concentration in Bangkok environment.

Abstract: This study aims to assess possibility of health risk attributed to nuisance dust on people living and working on roadside areas nearby Mahasarakham University (MSU). Nuisance dust was measured during November 2012 to May 2013 covering a school semester and a school break. All samples for Ban Tha Kong Yang roadside area showed high level of ambient aerosol with size less than 10 micron and the level was exceeding the national ambient air quality standard of 0.12 mg m-3 . Approximately half of the samples taken for Ban Kham Riang also show the same result. This suggests significant dust problem in these areas and could potentially cause adverse human health effects. Results from personal respirable dust sampling show that construction worker was exposed to the highest respirable dust concentration among three occupations, including security guard and street-food cooker. The levels were significantly higher with longer time on the road and having earth moving activity nearby. Occupational exposure to respirable dust, however, was not exceeding the US Occupational Safety and Health Administration standard of 5 mg m-3.

Abstract: In this work, both batch method and column method were used to investigates the adsorption of Ni and Zn on different kinds of soils found in the Northeastern Thailand including clay, silt, and sand. The batch method was used to examine the adsorption isotherm and the effect of contact time, initial concentration, and temperature on the adsorption. The column method was used to simulate the real condition of wastewater adsorption. The results indicated that the adsorption isotherms were fitted with Freundlich and Langmuir isotherm. All soils adsorbed Ni better than Zn. The adsorption capacity of soils tended to increase when the temperature increased from 30°C to 50°C. Soil surface characteristic was an important factor that affected on the adsorption capacity of soils. For the column test, the adsorption decreased with the increasing amount of metal solution. Leaching of the metal occurred in a fractional volume.