Nipon Pisutpaisal

Kinetics of Biohydrogen Production from Ozonated Palm Oil Mill Effluent Using C. butyricum and C. acetobutylicum Co-Culture

Kinetics of mesophilic biohydrogen production from ozone-pretreated palm oil mill effluent (POME) using C. butyricum and C. acetobutylicum co-culture was investigated. All experiments were setup in 0.5-L batch reactors under mesophilic condition (37°C), pH 6, and POME concentration of 5,000-30,000 mg COD L-1. At the concentration of 15,000 mg COD L-1, maximum hydrogen production yield for non-ozone pretreated POME and ozone pretreated POME were 318 and 122 mL g-1 CODremoved, respectively. Acetic and butyric acids were dominant fermentation products in liquid phase. Ozone-pretreatment of POME showed no significant improvement on the hydrogen production by the co-culture.

Carbon Mass Balance of Biohydrogen Production Process by Clostridium butyricum TISTR 1032: Effect of Oxygen Scavenger

A dark hydrogen fermentation process of food waste by Clostridium butyricum TISTR 1032 was examined under the condition of initial pH 6, 37oC and varied condition with oxygen scavenger in 5 L semi-batch reactors. Results showed that oxygen scavenger significantly elevated the maximum rate of hydrogen production (Rm) (203.5 mL h-1) compared to that without oxygen scavenger (30.6 mL h-1). However, it did not improve the maximum cumulative hydrogen production (Hmax). Carbon mass balance was used to explore the direction of fermentative process including toidentify type of fermentative process. Butyric acid fermentation was recognized as the fermentation type of this study under both conditions. Drop of pH and accumulation of total undissociated acid considerably reduced the hydrogen production.

Treatment of Palm Oil Mill Effluent by Electrocoagulation Process

The purpose of current study was to examine the ability of electrocoagulation in decreasing chemical oxygen demand (COD) and total suspended solid (TSS) constituted in palm oil mill effluent. Bench-scale batch reactor containing two aluminum or steel plates (10 cm width × 30 cm height with 0.1 cm thickness) serving as electrodes with the interval distance of 3 cm was set up. The wastewater with COD concentration of 68,425 mg L-1 was treated in the reactor under the varied direct currents (0.3-1.3 A) and contact time (30-120 min). Sodium chloride was added to the wastewater to obtain the final concentration of 2 g L-1 (conductivity of 10 ms) prior to being fed into the reactor. The results showed that higher treatment efficiency when the aluminum was used as electrodes compared to the steel. COD removal efficiency was directly proportional to the contact time. The maximum COD and TSS removal observed at 1.3 A current input and 60 min contact time are 74.1 and 77.0%, respectively.

Bioelectricity Generation from Wastewaters in Microbial Fuel Cells

The study investigated bioelectricity generation from three types of wastewaters including artificial (AW), buffered brewery (BW) and buffered canteen (CW), in double chamber microbial fuel cells (MFCs). The biochemical oxygen demand (BOD) concentrations of influent were varied in the range of 125 - 1000 mg L-1. Influent pH and operation temperature were fixed at 7 and 30oC. 0.35 mL min-1 wastewater was fed into a half-cell anodic chamber, while 5 mL min-1 oxygen-saturated distilled water was fed into a half-cell cathodic chamber. The circuit resistance was fixed at 10 ohms. The results showed that maximum current output obtained from AW, BW and CW with the initial BOD concentration of 1000 mg L-1 were 0.92, 0.78 and 0.70 mA, respectively. The currents were directly proportional to the BOD concentrations in the influent for all wastewaters. The maximum BOD removal of AW, BW and CW was 90, 65 and 75%, respectively.

Impact of Glycerol Concentration on Lactic Acid Fermentation

Lactic acid was fermented from glycerol under condition of 37oC, pH 7 and varying glycerol concentration range of 10-85 g L-1 using 3 different pure cultures, Lactobacillus leichmanii, Lactobacillus delbrueckii, and Corynebacterium glutamicum. In 45 g L-1 glycerol–containing MRS medium, L. delbrueckii and L. leichmanii produced maximum lactic concentration of 32.6 and 23.5 g L-1, respectively. Concentration of lactic acid increased with the increase of glycerol concentration range of 0-45 g L-1. No lactic acid was produced at glycerol greater than 45 g L-1.