Wednesday, August 19, 2009
Tuesday, August 18, 2009
Monday, August 17, 2009
Sunday, August 16, 2009
Combination of ozonation with conventional aerobic oxidation for distillery wastewater treatment [An article from: Chemosphere] Review
This digital document is a journal article from Chemosphere, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Laboratory-scale experiments were conducted in order to investigate the effect of ozone as pre-aerobic treatment and post-aerobic treatment for the treatment of the distillery wastewater. The degradation of the pollutants present in distillery spent wash was carried out by ozonation, aerobic biological degradation processes alone and by using the combinations of these two processes to investigate the synergism between the two modes of wastewater treatment and with the aim of reducing the overall treatment costs. Pollutant removal efficiency was followed by means of global parameters directly related to the concentration of organic compounds in those effluents: chemical oxygen demand (COD) and the color removal efficiency in terms of absorbance of the sample at 254nm. Ozone was found to be effective in bringing down the COD (up to 27%) during the pretreatment step itself. In the combined process, pretreatment of the effluent led to enhanced rates of subsequent biological oxidation step, almost 2.5 times increase in the initial oxidation rate has been observed. Post-aerobic treatment with ozone led to further removal of COD along with the complete discoloration of the effluent. The integrated process (ozone-aerobic oxidation-ozone) achieved ~79% COD reduction along with decoloration of the effluent sample as compared to 34.9% COD reduction for non-ozonated sample, over a similar treatment period.
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Saturday, August 15, 2009
Long-term aerobic cometabolism of a chlorinated solvent mixture by vinyl chloride-, methane- and propane-utilizing biomasses [An article from: Journal of Hazardous Materials] Review
This digital document is a journal article from Journal of Hazardous Materials, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
The aerobic cometabolic biodegradation of a mixture of chlorinated aliphatic hydrocarbons (CAHs) including vinyl chloride (VC), cis- and trans-1,2-dichloroethylene (cis-DCE, trans-DCE), trichloroethylene (TCE), 1,1,2-trichloroethane (1,1,2-TCA) and 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) was investigated at both 25 and 17^oC by means of bioaugmented and non-bioaugmented sediment-groundwater slurry microcosm tests. The goals of the study were (i) to study the long-term aerobic biodegradation of a CAH mixture including a high-chlorinated solvent (1,1,2,2-TeCA) generally considered non-biodegradable in aerobic conditions; (ii) to investigate the efficacy of bioaugmentation with two types of internal inocula obtained from the indigenous biomass of the studied site; (iii) to identify the CAH-degrading bacteria. VC, methane and propane were utilized as growth substrates. The non-bioaugmented microcosms were characterized, at 25^oC, by an average 18-day lag-time for the direct metabolism of VC (accompanied by the cometabolism of cis- and trans-DCE) and by long lag-times (36-264 days) for the onset of methane or propane utilization (associated with the cometabolism of the remaining CAHs). In the inoculated microcosms the lag-phases for the onset of growth substrate utilization and CAH cometabolism were significantly shorter (0-15 days at 25^oC). Biodegradation of the 6-CAH mixture was successfully continued for up to 410 days. The low-chlorinated solvents were characterized by higher depletion rates. The composition of the microbial consortium of a propane-utilizing microcosm was determined by 16s rDNA sequencing and phylotype analysis. To the best of our knowledge, this is the first study that documents the long-term aerobic biodegradation of 1,1,2,2-TeCA.
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Friday, August 14, 2009
Combining anoxic denitrifying ability with aerobic-anoxic phosphorus-removal examinations to screen denitrifying phosphorus-removing bacteria [An article ... Biodeterioration & Biodegradation] Review
This digital document is a journal article from International Biodeterioration & Biodegradation, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Anaerobic-aerobic (or anaerobic-anoxic) enhanced biological phosphorus- removal (EBPR) processes were generally considered for P removal. However, some isolated polyphosphate-accumulating organisms (PAOs) or denitrifying P-removal bacteria (DPB) may have varied P-removal characteristics under different conditions. This study investigated proper screening procedures for isolating DPB from piggery sludge, enriched sludge, and winery sludge. We combined anoxic denitrifying ability with aerobic-anoxic P-removal examinations to screen the DPBs as compared with conventional anaerobic-aerobic and anaerobic-anoxic P-removal examinations. It was concluded that denitrification ability detection was recommended as the first step of screening. Subsequently, denitrifiers were cultured under an aerobic-anoxic single-stage process using oxygen and nitrate simultaneously as e^- acceptors to examine P-removal abilities. We chose single-stage aerobic-anoxic P-uptake denitrifiers (Types I and II) according to the purpose of P removal, whereas well-grown denitrifiers without obvious P removal might be induced by considerable PHB formation. Moreover, under anaerobic-anoxic P-removal examinations, most of the isolated DPBs had no obvious anaerobic P release, but did have significant anoxic P uptake. Pure isolated DPB cultures behaved like enriched sludge, which showed no anaerobic P release but achieved respective N- and P-removal efficiencies of 96% and 86%.
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