• Energy Research
• 6. Clean water close
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Abstract H2 produced by cyanobacteria is one of the interesting alternative energy carriers for the future. The filamentous N2-fixing cyanobacterium Anabaena siamensis TISTR 8012 is a potential microorganism for H2 production. It can produce H2 via both photosynthesis and nitrogen fixation processes. This study aimed to increase the efficiency of H2 production by immobilization of A. siamensis cells. The result showed that H2 production rate by A. siamensis grown in BG110 medium was higher than that in BG11 and Allen-Arnon media due to an increase of the heterocyst cells. The sulfur deprivation during adaptation period for 24 hours increased its H2 production rate. The optimal conditions for H2 production by immobilized cells were immobilization with alginate and using 150 gel beads in 20 mL glass vial. In immobilized cells, an addition of 0.5% fructose resulted in a 2-fold increase of H2 production rate. Finally, the reducing agents β–mercaptoethanol and methylviologen enhanced H2 production rate with 3.092 and 2.426 µmolH2 mg chl a-1 h-1, respectively, in A. siamensis immobilized cells whereas NADH, dithiothreitol and sodium dithionite were not capable of increasing H2 production rate.

AbstractAyutthaya is a popular tourist destination located about 76km north of Bangkok. The climate of the province is typical of Central Thailand, comprising three (cool, hot, and rainy) seasons, with relatively small changes in average temperatures but significantly varying rainfall patterns. In this study, we present a geographic information system (GIS) used for the assessment and monitoring of the pollution in the watershed. The ArcInfo-based system combines geographic, meteorologic and hydrologic data for multiple uses. Water quality management is based on composite water quality index and corresponding water quality classes. The chief input parameters include temperature, pH, faecal bacteria count (FCB), dissolved oxygen (DO), nitrate (NO3), total phosphates (PO4), biochemical oxygen demand (BOD), suspended solids (SS), and total solids (TS), together with population density, rainfall and land-use. The initial results of year 2008-2009 show that water quality derogation is strongly related to high population density in the central (new City) districts that also affect the historical City. In addition, increased runoff from the mainly northern agricultural districts carries significant PO4, NO3, and BOD pollution to the Pa Sak River in the rainy season. The relationship between diversity index of mollusks and BOD, DO and WQI show the some correlate results of diversity index(H) and the quantity of oxygen in the water(DO). The low of diversity index almost locate at area of low DO. For other water quality indexes, there are no significant results in relation with diversity index of mollusks.

AbstractThe potentiality in biogas production from anaerobic co-digestion of canned seafood wastewater (CSW) with glycerol waste (GW) was investigated. Methane yields from anaerobic co-digestion of CSW with 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10% (v/v) of GW were 577, 265, 101, 51, 11, 9, 4, 3, 2 and 2mLCH4/g VS-added, respectively. The anaerobic co-digestion of 99% CSW with 1%GW was the optimal mixture ratio for methane production with a maximum methane yield was 577mLCH4/g VS-added and 97% biodegradability. Meanwhile, the maximum methane yield of 1%GW and 100%CSW were 211 and 278mLCH4/g VS-added. Methane yield increased by 108% when compared with digested CSW alone. The maximum methane production from anaerobic co-digestion of 99%CSW with 1%GW was 5.8 m3 CH4/m3 of mixed wastewater and electricity production of 1 m3 mixed wastewater would be 207MJ or 58 kWh of electricity. Continuous methane production from anaerobic co-digestion of CSW with 1% GW in up-flow anaerobic sludge blanket (UASB) reactors gave methane production rate of 2.33 LCH4/L-reactor.day.

AbstractSalinity-gradient solar pond is one type of solar collector with the ability to store thermal energy for long period of time and lower cost of construction compared with the other type of solar collector. It can collect and store solar heat at temperatures up to 80°C. A system in which heat from the lower zone is transferred to the hot surface of the thermoelectric modules using gravity- assisted heat pipes as thermosyphons has been investigated experimentally.The temperature difference between the lower convective zone and the upper convective zone is applied across the hot and cold surfaces of the thermoelectric modules. In the salinity gradient solar pond, a insulated solar pond with a surface area of 7 m2 and a depth of 1.3 m was built at Rajamangala University of Technology Isan Khon Kaen Campus,Thailand to conduct performance experiments. From the results of experiment by using water as working fluid, the temperature of the solar pond in lower convective zone is at 50°C.It can be seen that the thermoelectric is able to generate electricity at 36.25mV. Using R134a as a working fluid, the temperature of heat pond in lower convective zone is at 41°C.Due to this, thermoelectric generates electricity at 234.25mV.. Research results in the present work indicate that there is a significant potential for electric power generation from small solar ponds through a simple and passive device incorporating thermosyphons and thermoelectric cells.

AbstractThis work aimed to study and identify the optimum sub-critical water pretreatment conditions of sugarcane bagasse to increase the enzymatic digestibility of the cellulose fraction for subsequent bioethanol production. Sugarcane bagasse was pretreated with sub-critical water under several operating conditions; reaction temperature (126.36°C to 193.64°C), reaction time (3.18min to 36.82min), and bagasse/water ratio (1/4.64 to 1/11.36) in 600mL autoclave reactor. These operating conditions were optimized by using central composite design (CCD) and response surface methodology (RSM). From the study, it was found that the optimum pretreatment condition for producing sugars was 169.66°C, 19.41min, and 1/6.85 bagasse to water ratio.

Abstract In this study, sulfated tin oxide was modified with cobalt oxide and aluminium oxide resulting in sulfated cobalt-tin (SO 4 2- /Co 2 O 3 -SnO 2 ) and sulfated aluminium-tin (SO 4 2- /Al 2 O 3 -SnO 2 ) mixed oxide catalysts, respectively. Their catalytic activities for esterification of free fatty acids (FFA) in crude palm oil were investigated. Cobalt-tin and aluminium-tin mixed oxides were prepared by co-precipitation method. The mixed oxides were further impregnated with sulfate ions by immersing in sulfuric acid solution, dried and calcined at 450-500 °C. The properties of SO 4 2- /Co 2 O 3 -SnO 2 and SO 4 2- /Al 2 O 3 -SnO 2 samples were determined by nitrogen adsorption, X-ray diffraction and potentiometric titration. The activities of SO 4 2- /Co 2 O 3 -SnO 2 and SO 4 2- /Al 2 O 3 -SnO 2 catalysts were tested in a stirred-tank reactor equipped with a reflux condenser. Esterification between crude palm oil containing 10-10.2 wt% of FFA and methanol was carried out at various reaction times. The comparison in the catalytic activities of SO 4 2- /Co 2 O 3 -SnO 2 and SO 4 2- /Al 2 O 3 -SnO 2 was made. The results showed that the SO 4 2- /Al 2 O 3 -SnO 2 had higher catalytic activity than SO 4 2- /Co 2 O 3 -SnO 2 in esterification of FFA to produce methyl esters.

AbstractAir-cathode single-chamber microbial fuel cells (SCMFC) using the heat pretreated seed inoculation showed shorter period of biofilm formation with the maximum current output after 25 days inoculation when compared to the non-heat pretreated seed inoculation (45 days). The results showed the high performance of the heat pretreated seed inoculation in term of a peak of voltage and current generation, except the high COD and reducing sugar removal. Better voltammogram in oxidation and reduction peaks of the heat pretreated seed anode biofilm was observed. The current densities increased with the increases of wastewater concentrations and obtained maximum of 7.37mA m-2 of 3,000mg COD L-1 for the heat pretreated seed inoculation. In addition, the current outputs and wastewater concentrations displayed a linear correlation in the concentration range of 500 to 3,000mg COD L-1 (r2=0.96).