Enhancing Bio-Electricity Generation Using Novel Model of Ceramic-Separator Microbial Fuel cell with a Laccase-Based Cathode

บทคัดย่อ เยื่อแลกเปลี่ยนโปรตอนเป็นองค์ประกอบสำคัญที่มีอิทธิพลต่อต้นทุนในการเดินระบบ การบำบัดสารปนเปื้อนในน้ำเสียและการผลิตกระแสไฟฟ้าในเทคโนโลยีเซลล์เชื้อเพลิงจุลินทรีย์ จากการศึกษาที่ผ่านมาวัสดุที่มีรูพรุนหลากหลายชนิดถูกนำมาประยุกต์ใช้ รวมถึงแผ่นเซรามิก ในงานวิจัยนี้เซลล์เชื้อเพลิงจุลินทรีย์เซรามิกรูปแบบใหม่ถูกพัฒนาขึ้น โดยใช้ขั้วแคโทดที่ผิวมีจุลินทรีย์แบบใช้อากาศเคลือบอยู่ซึ่งที่ประกอบขึ้นจากการเพาะเลี้ยงเชื้อยีสต์ Galactomyces reessii ที่ผลิตแลคเคสบนวัสดุใยมะพร้าวและวางบนแผ่นตาข่ายสเตนเลส ใช้ผ้าคาร์บอนเป็นขั้วแอโนด และใช้แผ่นเซรามิกที่มีความหนา 0.2 เซนติเมตร เป็นแผ่นกั้นประจุ ใช้น้ำเสียยางพาราที่มีความเข้มข้นซัลเฟตเริ่มต้นที่ 500 มิลลิกรัมต่อลิตร และค่าซีโอดีเริ่มต้นที่ 1,000 มิลลิกรัมต่อลิตร จากการศึกษาพบว่าระบบเซลล์เชื้อเพลิงจุลินทรีย์เซรามิกรูปแบบใหม่ที่พัฒนาขึ้นซึ่งทำการเดินระบบแบบกะ สามารถผลิตความหนาแน่นกำลังไฟฟ้าสูงสุดที่ 310.78±1.94 มิลลิวัตต์ต่อลูกบาศก์เมตร ความหนาแน่นกระแสไฟฟ้าสูงสุดที่ 3,392.09±16.07 มิลลิแอมแปร์ต่อลูกบาศก์เมตร และมีค่าความต้านทานภายในระบบเท่ากับ 330 โอห์ม ระบบนี้สามารถบำบัดซีโอดีได้ที่ร้อยละ 78.70±0.56 และบำบัดสารซัลเฟตที่ร้อยละ 88.85±0.50 ดังนั้นเซลล์เชื้อเพลิงจุลินทรีย์เซรามิกรูปแบบใหม่มีศักยภาพในการพัฒนาเพื่อใช้ในการบำบัดน้ำเสียในระดับอุตสาหกรรม คำสำคัญ: แผ่นกั้นเซรามิก ใยมะพร้าว พลังงานไฟฟ้า แลคเคส เซลล์เชื้อเพลิงจุลินทรีย์ สแตนเลส ซัลเฟต ABSTRACT In microbial fuel cell (MFC), a proton exchange membrane (PEM) is an important part that affects the cost of the operation and the performance in contaminants elimination and electricity  production. Various types of porous materials have been studied as alternatives to ion separators including ceramic. In this work, a novel model of ceramic-separator microbial fuel cell (CMFC) consisted of air-cathode based on coconut coir with laccase producing yeast Galactomyces reessii on stainless steel net, the carbon cloth anode and ceramic plate with 0.2 cm of thickness. The rubber wastewater (initial 500 mg/L sulfate concentration and 1,000 mg/L COD concentration) was used as an anolyte. The maximum power density of 310.78 ± 1.94 mW/m3, the maximum current density of 3,392.09 ± 16.07 mA/m3 and the internal resistance of 330 Ω were obtained for CMFC by laccase-based cathode under batch processing. Moreover, the COD removal of 78.70 ± 0.56% and the sulfate removal of 88.85 ± 0.50% were achieved. Hence, the ceramic-separator microbial fuel cell with a laccase-based cathode are potential candidate for the development of industrial-scale wastewater treatment plants.Keywords: Ceramic-separator, Coconut coir, Electrical energy, Laccase, Microbial fuel cell, Stainless steel, Sulfat

Nutrient optimization of polyhydroxyalkanoate production from palm oil fiber by Ralstonia eutropha TISTR 1095 using response surface methodology

Polyhydroxyalkanoate (PHA) is polyesters formed in several bacteria as a carbon or energy storage under some nutrientlimitation. Ralstonia eutropha has potential to produce PHA from various substrates, including carboxylic acids. In this research,the nutrient optimum to produce PHA from carboxylic acid was studied by using response surface methodology. Thecarboxylic acids were produced by anaerobic palm oil fiber fermentation for 7 days. Then Ralstonia eutropha TISTR 1095was cultured in fermented broth containing 840 mg/l of acids. The interaction of two factors at the same time was investigated.The effects of propionic acid, butyric acid, (NH4)2SO4 and K2HPO4 addition were examined. The result showed that the nutrient optimum for PHA production was fermented broth with nutrient addition (2.50 g/l propionic acid, 6.53 g/l butyric acid,1.53 g/l, (NH4)2SO4 and 0.03 g/l K2HPO4). The cell concentration, PHA concentration, and PHA content were 1.53 g/l, 0.70 g/l and 46.5%, respectivel

Enhancement of sludge granulation in anaerobic treatment of concentrated latex wastewater

Recently, the upflow anaerobic sludge blanket (UASB) reactor has become attractive for wastewater treatment with low energy requirement and biogas production. However, the start-up of an UASB reactor depends on the formation of granules. Therefore, this research aims to study the effect of AlCl3, CaCl2 and temperature on the granule formation process using real concentrated latex wastewater. The result shows that the optimum chemicals concentration of AlCl3 at 300 mg/l enhanced the biomass accumulation and sludge formation process. Approximately 50% of large granular size (0.5 mm < d < 0.8 mm) was obtained with a specific methanogen activity (SMA) of 0.14 gCOD/gVSS/d after 28 days. The COD removal efficiencies were gradually improved until reaching 50% at the end fermentation. Furthermore, the result shows that increasing temperature did not promote granular size. In addition, the granular sludge (R1) (positive control), crushed sludge (R2) and crushed sludge with 300 mg/l of AlCl3 (R3) was examined in 2-l UASB system. It was also found that reactor with AlCl3 supplement (R3) could provide a large granule size (d > 0.8 mm) within 35 days, whereas the large granular sizes in reactorwithout AlCl3 supplement (R2) became visible within 63 days. Moreover, this experiment found that R1, R2 and R3 could reach steady state within 40, 55 and 45 days, respectively

Integrative Effects of Sonication and Particle Size on Biomethanation of Tropical Grass Pennisetum purpureum Using Superior Diverse Inocula Cultures

Biogas from the fast growing crop, Pennisetum purpureum, has received considerable attention in Southeast Asia since wastewater and bio-waste materials are almost completely utilized. To overcome slow hydrolysis, a rate-limiting step in anaerobic digestion of lignocellulosic biomass, superior microorganism culture, size reduction, and sonication pretreatment were co-applied. In the first experiment, the selection of anaerobic microbial culture to be used in digestion, so-called inoculum, was carried out. Specific anaerobic activities for hydrolysis and methanogenesis of sludge from different sources, a slurry digester of cattle farm (CF) and a wastewater digester of rubber latex factory (RL) were assessed. Results revealed a remarkable synergistic capability in the combined sludge, adding 10% and 49% to the overall biomethanation efficiency over the individual CF and RL sludges. In the second part, interactive effects of size reduction and sonication intensity were studied. Biomethanation efficiency as methane yield increased by 62% by size and 115% by sonication variation, but when optimally combined an additional gain of 40% was recorded. The regression model generated could estimate the energy yield increase as a function of size and sonication intensity with a satisfactory statistical precision R2 of 0.945

Bio-Succinic Acid Production from Palm Oil Mill Effluent Using <i>Enterococcus gallinarum</i> with Sequential Purification of Biogas

Bio-succinic acid production using microorganisms has been interesting as an environmentally friendly process. Palm oil mill effluent (POME) was considered as a cheap substrate to lower the cost of production. It was revealed that 2-fold diluted POME produced more succinic acid than undiluted and 5-fold diluted POME. In addition, the effects of various neutralizing agents on succinic acid production utilized to manage pH and CO2 supply indicated that the utilization of MgCO3 as a neutralizing agent produced succinic acid of 11.5 g/L with a small amount of by-product synthesis. Plackett–Burman Design (PBD) was used to screen the most significant nutrients for bio-succinic acid production from 2-fold diluted POME using E. gallinarum. From the Pareto chart, MgCO3 and peptone presented the highest positive effect on the production of succinic acid. In addition, Box–Behnken Design (BBD) was conducted to increase bio-succinic acid production. Experiments showed the highest production of succinic acid of 23.7 g/L with the addition of 22.5 g/L MgCO3 and 12.0 g/L peptone in 2-fold diluted POME. Moreover, the experiment of replacing MgCO3 with CO2 from biogas resulted in 19.1 g/L of succinic acid, simultaneously creating the high purity of biogas and a higher CH4 content

Effect of organic loading rate on methane and volatile fatty acids productions from anaerobic treatment of palm oil mill effluent in UASB and UFAF reactors

Anaerobic treatment of palm oil mill effluent (POME) with the separation of the acidogenic and methanogenic phase was studied in an up-flow anaerobic sludge blanket (UASB) reactor and an up-flowanaerobic filter (UFAF) reactor. Furthermore, the effect of OLR on methane and volatile fatty acid productions in UASB and UFAF reactors was investigated. In this research, UASB as acidogenic reactor wasused for volatile fatty acid production and UFAF as methanogenic reactor was used for methane production. Therefore, POME without pH adjustment was used as influent for the UASB reactor. Moreover, the syntheticwastewater with pH adjustment to 6.00 was fed into the UFAF reactor. The inoculum source for both reactors was the combination of POME sludge collected from the CSTR of a POME treatment plant and granulesludge collected from the UASB reactor of a frozen sea food industry treatment plant. During experimental operation, the organic loading rate (OLR) was gradually increased from 2.50 to 17.5 g COD/l/day in theUASB reactor and 1.10 to 10.0 g COD/l/day in the UFAF reactor. Consequently, hydraulic retention time (HRT) ranged from 20.0 to 2.90 days in the UASB reactor and from 13.5 to 1.50 days in the UFAF reactor.The result showed that the COD removal efficiency from both reactors was greater than 60.0%. In addition, the total volatile fatty acids increased with the increasing OLR. The total volatile fatty acids and acetic acidproduction in the UASB reactor reached 5.50 g/l and 4.90 g/l, respectively at OLR of 17.5 g COD/l/day and HRT of 2.90 days before washout was observed. In the UFAF reactor, the methane and biogas productionincreased with increasing OLR until an OLR of 7.50 g COD/l/day. However, the methane and biogas production significantly decreased when OLR increased up to 10.0 g COD/l/day. Therefore, the optimum OLR inthe laboratory-scale UASB and UFAF reactors were concluded to be 15.5 and 7.50 g COD/l/day, respectively