Advanced Materials Research Vols. 931-932

Abstract: Tapioca starch manufacturing generated a large amount of wastewater containing high organic matter contents. Wastewater from tapioca starch manufacturing thus had a high potential for biogas recovery. In Thailand, biogas recovery from tapioca wastewater has been performed via a UASB system for large-scale manufacturers and a cover lagoon system for small-to medium-scale manufacturers. Settling the UASB system on a tapioca starch processing site required high investment and operation cost, whilst settling the cover lagoon system required a land area. There were a number of studies identifying that the anaerobic filter system, using natural materials as support media, had a high efficiency for treatment and biogas recovery of agro-industrial wastewater containing high organic contents. This research was begun with the idea to seek for a proper technique for treatment and biogas recovery, with high effectiveness and low cost, of wastewater from small-to medium-scale tapioca production plants. The studied materials, used as support media, were two natural materials (burnt corn cobs and charcoal) and synthesis material (plastic balls). The research experiment has been undertaken, using three laboratory-scale anaerobic filter reactors. The initial findings have showed that wastewater treatment efficiencies, as well as biogas production capacities, of the two reactors containing selected natural support media types and the one containing synthesis media type were in the same range. The COD removal efficiencies were 95.42% to 97.90%. The SS removal efficiencies were 78.12% to 85.32%. The methane contents of biogas produced were 73.45% to 75.06%.

Abstract: There are increasing demands to substitute the plastic from the petrochemical industry with bacterial cellulose which were produced from microorganisms as Acetobactor xylinum strain. The aim of this study was to produce bacterial cellulose from banana peels which are agricultural waste around Walailak University area. The banana peels were used as a carbon source together with nutrient medium for the growth of bacteria. The ratio between Hestrin and Schramm nutrient medium (HS) with banana peel to DI water was 1:0.5, 1:1, and 1:1.5 (%V/V). Sugar content in banana peel (control) was 4.0% Degree Brix. The initial pH was 6.0 and sugar contents varied in this study were 5.5%, and 11% Degree Brix. A.xylinum dosages used in the cultivation were 5, 6.67, and 8.33 (%V/V) respectively. The cultivation times were 15 days at the temperature of 30 °C. As a result, the highest yield of produced bacterial cellulose was 19.46 gram and the best condition which maximum yield of bacterial cellulose 1.95% can be obtained was 11% (Brix) of sugar content, 6.67 (%V/V) of A.xylinum added, and 1:1.5 of banana peel to DI water. The physical properties of bacterial cellulose were studied with ATR-FTIR spectroscopy which shown adsorption spectrum at 3279, 2915, 1627 and 1013 cm^-1 corresponding to the-OH,-CH,-CH₂ and carboxyl function groups, respectively. Glass transition Temperature (T_g) was 116.85°C. Tensile strength was measured with UTM and had average value of 41.13±5.43 Mpa. The bacterial cellulose had moisture content of 90.00±0.02%. The synthesized bacterial cellulose can be used as adsorption media and also has its chemical properties like petroleum polymer. Result suggested that the similar property can be observed when compared with petroleum plastic, however with the exception of methyl group (CH₃). Methyl group which can be found in plastic synthesized from petrochemical is responsible for the strength of plastic. Thus, bacterial cellulose, synthesized in this study, is not as strong as petrochemical plastic. But it can be used to produce bio-plastics because of the-CH and-CH₂ functional group attached. With the similar physical and chemical properties to those of petrochemical plastic, bacterial cellulose can be used as biopolymer.

Abstract: Soil biocementation is the new technique using biochemical process to initiate the crystal forms of calcium carbonate (CaCO₃) to bind the soil particles resulting in soil mechanical improvement. This research examines the effect of urease (UR) dosages on the strength development of sandy soil in biocemented sand reactor (BSR). Our results found that urease dosages between 5-30% (v/v) affected the strength development in sandy soil in term of shear modulus (G). Addition of UR resulted on an increase of solution pH. Highest solution pH during the treatment was found at UR 20%, as well as highest G value. Formation of CaCO₃ in biocemented sand could be useful for the stabilization of the sand or earth structures.

Abstract: This article presents a statistical correlation between GPS precipitable water vapor and meteorological data, i.e., surface temperature, air pressure, relative humidity, dew point temperature, and water vapor pressure by using linear regression. The data, recorded over a 4-year period, was used as an estimation of missing GPS precipitable water vapor data from discontinuous recordings. A multiple linear regression equation showed a correlation among zenith wet delay (ZWD), water vapor pressure (e) and surface temperature (T) was ZWD(e,T) = 17.4952e-0.8281T-93.164, with a coefficient of determination (R²) of 0.725, a mean absolute error of 8.71 mm, a root mean square error of 10.39 mm, and a mean absolute percentage error of 18.63%. The equation obtained can be used to estimate GPS precipitable water vapor data which is missing from recordings due to accident or technological error.

Abstract: Information on spatial variability of Sodium Adsorption Ratio (SAR) is useful for implementation of appropriate control measures for the salt-affected soils. The major objective of this study was to use geostatistics to describe the spatial variability of (i) the SAR and consequently (ii) the soil sodicity, in areas of different classes of salt-affected soils. Attention was on areas of very severely salt-affected soils (class 1), severely salt-affected soils (class 2), and moderately salt-affected soils (class 3). For each class, 2 study sites were chosen, totally 6 sites were taken into consideration. In each site, 100 soil samples were collected at 0-30 cm depth according to the stratified systematic unaligned sampling method in the dry season of 2012, and analyzed for the SAR in the laboratory. Descriptive statistics and Geostatistics were applied to describe the variability and spatial variability of SAR and soil sodicity, respectively. The result revealed very high variability of SAR. Descriptive statistics showed the CV values of ≥ 35% for every site of every class. When using semivariogram to describe the spatial correlation of SAR, it was found that in 3 study sites, the semivariogram models fitted well with the corresponding semivariogram samples indicating spatial correlation of SAR in the areas. In these cases, the Ordinary Kriging was applied to generate soil sodicity map. The relatively short range values especially for class 1 indicated very high variation of SAR. However, for the other 3 study sites, the linear models were fitted indicating no spatial correlation. Consequently, Trend Surface Analysis was applied instead. According to the soil sodicity maps generated in this study, the areas of class 1 were entirely occupied by strongly sodic soils. For classes 2 and 3, the soils in all study sites belonging to these classes included normal and slightly sodic soils of different proportions. Furthermore, inconsistency of the spatial variability patterns of SAR was found even in areas within the same class of salt-affected soils. As a result, prior to the intensive management of this problem soil in a particular area, investigation on the spatial variability pattern should be performed

Abstract: This study focused on quality of shallow groundwater collected around Laemchabang sanitary landfill Chonburi Province, Thailand. The sixteen public shallow wells were collected and analyzed for pH, cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺), anions (HCO^-_3, Cl^- and SO₄ ^2-) and metals (As, Fe, Mn, Zn and Al). The results were reported by statistical and correlation techniques. It was found that, in some wells, metals such as Fe and Mn exceeded the acceptable limits. Thus, shallow groundwater around Laemchabang Sanitary Landfill would not be suitable for drinking. According to correlation analysis, pH value is positively correlated with HCO^-_3, Fe and Al. Ca²⁺ and Mg²⁺ are positively correlated with HCO^-₃ and Cl^-. Arsenic is positively correlated with Fe and Mn. Most shallow groundwater samples in this area are the mixed type, Ca (Mg)Cl (SO₄) type, which may occur from water-rock interaction and leakage from landfill to groundwater system.

Abstract: This study is the beginning of attempts to obtain existing data of estrogens contamination in wastewater treatment plants (WWTPs) in Bangkok Metropolitan area. Influents and effluents of seven WWTPs in Bangkok, and water samples from Bang-sue canal (receiving water from Chatuchak (CTC)-WWTP) and Chaopraya River (as receiving water from Chongnonsri (CNS)-WWTP) were collected by grab sampling. The sampling and analyses were done three times in a year round, during March to April 2010, October 2010, and January 2011. 17β-estradiol (E2) was found as in the majority in most samples including the surface water samples. In addition, the results of receiving water samples in both locations show that downstream (of discharged point) estrogens were a little higher than upstream ones. This could imply that WWTPs might be the important sources of estrogens contamination in surface (receiving) waters in Bangkok area and that the biological wastewater treatment processes currently used in WWTPs could not completely remove these estrogens.

Abstract: Recently, usage of the metal-based pesticide especially manganese (Mn) and copper (Cu) have been widely used in the agricultural area around the Lam Takhong Reservoir; the major water resource of Nakhon Ratchasima Province and the Southern I-Sarn. The exposures of these metals can causes neurological and Parkinson diseases. Therefore the objectives of this study were to investigate Mn, Cu, and Fe contaminations in the reservoir as well as the environmental risks by using hazard quotient (HQ). The results showed that the average concentrations of Mn, Cu, and Fe in water column were 0.05 mg/l, 0.01 mg/l, 0.39 mg/l in dry season and 0.08 mg/l, 0.01 mg/l, 0.53 mg/l in wet season, respectively. Mn and Cu concentrations were in normal range except those of Fe that were extremely high. Also, Mn and Cu in sediment were found in the normal range. Interestingly, high concentrations of Fe in sediment were found at many stations with respect of the parent materials in this area. Fortunately, there were no risks of Mn and Cu in both water column and sediment. However, Fe in sediment exceeded the recommended guideline. These results suggested that using Mn/Cu-based synthetic pesticides in this area might be limited with respect of Fe abundance that could enhanced the toxicity of Mn/Cu and might increased the incidents of neurological and Parkinson diseases.

Abstract: Background: Saphan Hin is well known park located in the southern east coast of Phuket. Marine litter, especially light and floatable litter such as plastic, is known to be the cause of death in marine animals. Therefore, prediction of light floatable marine litter will greatly help to understand behavior of marine litter transportation at Saphan Hin and leads to proper waste management in vulnerable areas.

Abstract: The Lower Yom River Basin is located in the north of Thailand. This study carried out to calibrate and validate using SWAT model in terms of streamflow and sediment concentration hydrographs (Year 2000-2012) for 3 RID streamflow gauging stations (the Royal Irrigation Department). The nitrates concentrations simulate have been influenced of land use changes during last ten years. Optimal values of model parameters derived from calibration and validation processes, which showed well fitted between observed and simulated results. In the last decade, particular in Lower Yom River, the land use change gradually transformed to be more paddy field and has been increased 127.48 km² (approx. 0.87% increase), followed by urban area, which has been increased 196.66 km² (approx. 1.35% increase), respectively. Average monthly concentration of nitrate increased 38.28 mg/l (approx.13.40 % increase), 43.17 mg/l (approx.12.00% increase), 43.02 mg/l (approx. 8.60% increase) at station Y.6, Y.4 and Y.17, respectively. Accordingly, on the basis of the results presented in this study, land use changes can significantly affect on concentrations of nitrate.