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is faster than via autotrophic pathway. While, from nitrate to nitrite (NO3 − → NO2 − ), the reaction rate via autotrophic denitrification (S2− → S0 ) is faster than via heterotrophic denitrification (acetate → CO2 ) pathway. References
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Wang, A.J., Du, D.Z., Ren, N.Q., van Groenestijn, J.W., 2005. An innovative process of simultaneous desulfurization and denitrification by Thiobacillus denitrification. J. Environ. Sci. Health A 40, 1939–1949.
doi:10.1016/j.jbiotec.2008.07.1513 VII4-P-008
Chen, C., Ren, N.Q., Wang, A.J., 2008. Simultaneous biological removal of sulfur, nitrogen and carbon using EGSB reactor. Appl. Microbiol. Biotechnol. 78, 1057–1063. Wang, A.J., Du, D.Z., Ren, N.Q., Van Groenestijn, J.W., 2005. An innovative process of simultaneous desulfurization and denitrification by Thiobacillus denitrification. J. Environ. Sci. Health A 40, 1939–1949.
Bioremediation of a petroleum-hydrocarbon contaminated aquifer by in situ biosparging system H.Y. Chien 1 , C.M. Kao 1,∗ , S.C. Chen 2 , Y.L. Chen 2 1
Institute of Environmental Engineering, National Sun Yat-Sen University, Taiwan 2 Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung 804, Taiwan
doi:10.1016/j.jbiotec.2008.07.1512 VII4-P-007 Optimal process pattern for simultaneous sulfur, nitrogen and carbon removal Chen 1,2 ,
Chuan Jong Lee 2,3
Aijie
Wang 1,2,∗ ,
Nanqi
Ren 1,2 ,
Xu
Zhou 1,2 ,
Duu-
1
State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China 2 School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China 3 Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan E-mail address:
[email protected] (A. Wang).
In order to obtain an optimal process pattern for simultaneous sulfur, nitrogen and carbon removal, an upflow anaerobic fixed-bed reactor (UAFB) and an expanded granular sludge bed (EGSB) reactor were conducted under same conditions (Wang et al., 2005). Directional domesticated activated sludge and mature granules were incubated in each reactor during the startup in order to cultivate a microbial community consisting of autotrophic sulfide-oxidation bacteria, denitrifying bacteria and heterotrophic denitrifiers (Chen et al., 2008). The experimental results showed that, there are no obvious differences in the removal efficiencies of sulfide, nitrate, and acetate below the loadings of 2.40 kg S m−3 d−1 , 1.26 kg N m−3 d−1 and 0.90 kg C m−3 d−1 under steady state and the removal rate of them were all nearly 100%. Meanwhile, insoluble elemental sulfur (S0 ) as one of the end products accumulated in two reactors and the theoretical S0 conversion rates of them, showing that above 95% of sulfide in the medium was converted to S0 . At higher loadings of 2.88 kg S m−3 d−1 , 1.51 kg N m−3 d−1 and 1.08 kg C m−3 d−1 , the removal rate of sulfide, nitrate and acetate in UAFB reactor decreased strongly to 74%, 50% and 40% in 9 days; however, high efficiency was achieved in EGSB reactor at the same loading and the sulfide and nitrate were completely consumed, more than 95% acetate was removed. To investigate the maximum capability of removing sulfide, nitrate and acetate for EGSB reactor, the loading was elevated to 4.92 kg S m−3 d−1 , 2.52 kg N m−3 d−1 and 2.72 kg C m−3 d−1 and the removal rate of them were all above 98%, 90% and 98% respectively with no accumulation of nitrite. These results suggested that EGSB reactor could be an optimal process pattern for simultaneous sulfur, nitrogen and carbon removal cause its efficiency is almost two times than that of UAFB reactor.
E-mail address:
[email protected] (C.M. Kao). In this study, a full-scale biosparging investigation was conducted at a petroleum-hydrocarbon spill site. Field results reveal that the natural attenuation was the main cause of the decrease in major contaminants [benzene, toluene, ethylbenzene, and xylenes (BTEX)] concentrations in groundwater before the operation of biosparging system. Evidence of the occurrence of natural attenuation within the BTEX plume include: (1) decrease of DO, nitrate, sulfate, and redox potential, (2) production of dissolved ferrous iron, sulfide, methane, and CO2 , (3) decreased BTEX concentrations along the transport path, (4) increased microbial populations, and (5) limited spreading of the BTEX plume. Field results also reveal that the operation of biosparging caused the shifting of anaerobic conditions inside the plume to aerobic conditions. This variation can be confirmed by the following field observations inside the plume due to the biosparging process: (1) increase in DO, redox potential, nitrate, and sulfate, (2) decrease dissolved ferrous iron, sulfide, and methane, (3) increased total heterotrophs, and (4) decreased total anaerobes as well as methanogens. Results of polymerase chain reaction, denaturing gradient gel electrophoresis, and nucleotide sequence analysis reveal that three BTEX biodegraders (Candidauts magnetobacterium, Flavobacteriales bacterium, and Bacteroidetes bacterium) might exist at this site. Results show that more than 70% of BTEX has been removed through the biosparging system within a 10-month remedial period at an averaged groundwater temperature of 18 ◦ C. This indicates that biosparging is a promising technology to remediate BTEX contaminated groundwater. Keywords: Biosparging; Natural attenuation; BTEX; PCR; DGGE doi:10.1016/j.jbiotec.2008.07.1514 VII4-P-012 Cyanide-generating bacteria for gold recovery from electronic scrap material Yen-Peng Ting ∗ , Chi Chong Tan, Van Anh Pham Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge Crescent, Singapore 117576, Singapore E-mail address:
[email protected] (Y.-P. Ting). Electronic wastes (or E-wastes) is recognised as a new emerging and fast-growing waste stream, and may be considered as a ‘secondary
References Chen, C., Ren, N.Q., Wang, A.J., Yu, Z.G., 2008. Simultaneous biological removal of sulfur nitrogen and carbon using EGSB reactor. Appl. Microbiol. Biotechnol. 78, 1057–1063.
∗ Corresponding author. Tel.: +886 7 525 4413; fax: +886 7 525 4449.
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ore’ for the recovery of some precious metals (such as gold) (Ten and Ting, 2003). The purpose of this study was to evaluate the use of bioleaching for the biomining of gold from E-wastes. Electronic scrap materials (ESM) from a local waste recycling company was physically and chemically characterised. The fine ESM showed a heterogeneous matrix with low specific surface area and contained 0.2% gold and more than 20% copper. Two cyanide-producing bacteria, Pseudomonas fluorescens and Chromobacterium violaceum were cultured, and three bioleaching methods were evaluated: one-step, two-step and spent medium bioleaching. In one-step bioleaching where the bacteria was inoculated in the presence of ESM in the batch culture, the optimal pulp density for bioleaching occurred at 5%w/v, with gold recovery at 26% and 29% by C. violaceum and P. fluorescens respectively. Copper recovery was similar for both the bacteria (at 20%). Both two-step and spent medium bioleaching were evaluated using 5% pulp density. In two-step bioleaching where the ESM was introduced into the culture two-days after the bacteria was inoculated, a gold recovery of about 30% was obtained for both the bacteria. Copper recovery was marginally higher (at 22% and 25% respectively) than in one-step bioleaching. The results showed that both C. violaceum and P. fluorescens were capable of bioleaching gold. Although C. violaceum has been reported for its cyanide producing (and thus metal leaching capability) (Campbell et al., 2001; Faramarzi et al., 2004), the use of P. fluorescens for bioleaching is shown for the first time. Indeed, P. fluorescens exhibited a higher growth rate, a higher metal resistance and hence better metal leaching kinetics than C. violaceum. References Campbell, S.C., Olson, G.J., Clark, T.R., McFeters, G., 2001. Biogenic production of cyanide and its application to gold recovery. J. Ind. Microbiol. Biotechnol. 26, 134–139. Faramarzi, M.A., Stagars, M., Pensini, E., Krebs, W., Brandl, H., 2004. Metal solubilization from metal-containing solid materials by cyanogenic Chromobacterium violaceum. J. Biotechnol. 113, 321–326. Ten, W.K., Ting, Y.P., 2003. Bioleaching of electronic scrap materials by Aspergillus niger. In: 15th International Biohydrometallurgy Symposium, vol. 1, Athens, Greece, September 14–19, 2003, pp. 137–1146.
doi:10.1016/j.jbiotec.2008.07.1515 VII4-P-013 Agricultural waste utilization for production of xylooligosaccharides and incorporation in yoghurt as functional ingredient Semee Mumtaz, Salim-ur-Rehman ∗ , Nuzhat Huma, Javed Aziz Awan National Institute of Food Science and Technology, University of Agriculture, Faisalabad, Pakistan E-mail address: drsalim
[email protected] ( Salim-ur-Rehman). Xylooligosaccharides (XOs) were extracted from four indigenous agricultural wastes including corncob, rice husk, almond shells and sheesham wood (Dalbergia sissoo) dust through chemical and enzymatic actions to evaluate potential of local agricultural wastes for XOs production. The methodology comprised of chemical pretreatment, i.e., soaking sheesham wood dust in 2 g/L H2 SO4 at 70 ◦ C for 15 h and other substrates in 1 g/L H2 SO4 at 65 ◦ C for 10 h followed by filtering and washing to pH 5.0. Slurry was subjected to steaming at 145 ◦ C for 30 min and the substrates were pounded to facilitate enzymatic hydrolysis with xylanase (5 U/g) at 55 ◦ C, pH 5.0. After refining, the XOs solution was spray dried. Both crude and refined XOs were measured with HPLC. Highest yield of XOs was obtained from corncobs followed by rice husk, almond shells and sheesham wood dust. The XOs were incorporated in yoghurt
by replacing sucrose at different ratios. The pH, titratable acidity, whey separation and sensory characteristics of yoghurt samples were determined at 0, 7, 14 days interval. Calorific value (CV) of the yoghurt decreased with an increase in concentration of XOs. No significant differences in sensory characteristics among all treatments were observed. doi:10.1016/j.jbiotec.2008.07.1516 VII4-P-014 Activated carbons based on solid residues from coffee biodiesel production Adriana S. Franca ∗ , Anne A. Nunes, Leandro S. Oliveira DEQ/UFMG – R. Espirito Santo 35 – 6◦ Andar, Belo Horizonte, MG, Brazil E-mail address:
[email protected] (A.S. Franca). Brazil is the largest coffee producer in the world, but the coffee beverage consumed in the country is of low quality, due to the presence of defective coffee beans, which represent approximately 20% of the total coffee production in Brazil (Oliveira et al., 2008). In view of such problem, studies are currently under development in order to find alternative uses for defective coffee beans. One of the alternatives being considered is biodiesel production, with the added advantage of allowing coffee producers to produce and use their own fuel (Oliveira et al., 2008). Unfortunately, the use of inedible vegetable oils for biodiesel production generates a considerable amount of solid residues (pressed seed cakes), which present an environmental problem in terms of adequate disposal. In order for such process to become environmentally favorable, alternative uses for such waste biomass should be sought. Recent studies have demonstrated that such type of residues can be used for adsorbent production (Garg et al., 2007; Karagöz et al., 2008). In view of the aforementioned, the objective of this study was to investigate the potential of defective coffee beans press cake to be used as an adsorbent for the removal of dyes from synthetic aqueous media. Batch adsorption tests were performed at 25 ◦ C and the effects of particle size, contact time, adsorbent dosage and pH were investigated. Preliminary adsorption tests indicated that thermal treatment is necessary in order to improve adsorption capacity, with microwave activation providing a significant increase in maximum adsorption capacity (68 mg g−1 ) in comparison to conventional activation in a muffle furnace (15 mg g−1 ). Adsorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, with the second-order model providing the best description of MB adsorption onto the prepared adsorbent. The experimental adsorption equilibrium data were fitted to Langmuir and Freundlich adsorption models, with the first providing the best fit. The experimental data obtained in the present study indicated that this type of waste material is a suitable candidate for use in the production of low cost adsorbents for removal of cationic dyes, thus contributing for the implementation of sustainable development in the biodiesel production chain.
Acknowledgement The authors acknowledge financial support from the following Brazilian Government Agencies: CAPES, CNPq and FAPEMIG. References Garg, U., Kaur, M.P., Garg, V.K., Sud, D., 2007. Removal of hexavalent chromium from aqueous solution by agricultural waste biomass. J. Hazard. Mater. 140, 60–68.
