The start‐up of anaerobic sequencing batch reactors at 20 °C and 25 °C for the treatment of slaughterhouse wastewater |
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Authors: | Daniel I Mass Lucie Masse Annie Verville Steve Bilodeau |
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Affiliation: | Daniel I Massé,Lucie Masse,Annie Verville,Steve Bilodeau |
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Abstract: | The objective of this research was to evaluate the feasibility, the stability and the efficiency of a start‐up at 20 °C and 25 °C of anaerobic sequencing batch reactors (ASBRs) treating slaughterhouse wastewater. Influent chemical oxygen demand (COD) and suspended solids concentrations averaged 7500 and 1700 mg dm?3, respectively. Reactor start‐up was completed in 168 and 136 days at 20 °C, and 25 °C, respectively. The start‐up process was stable at both temperatures, except for a short period at 20 °C, when effluent volatile fatty acid (VFA) concentrations increased from an average of 40 to 400 mg dm?3. Effluent quality varied throughout start‐up, but in the last 25 days of the experiment, as the ASBRs were operated under organic loading rates of 2.25 ± 0.21 and 2.86 ± 0.24 kg m?3 d?1 at 20 °C and 25 °C, respectively, total COD was reduced by 90.3% ± 1.3%. Methanogenesis was not a limiting factor during start‐up. At 20 °C, the limiting factor was the acidification of the soluble organics and, to a smaller extent, the reduction of propionic, isobutyric and isovaleric acids into lower VFAs. At 25 °C, the limiting factor was the hydrolysis of particulate organics. To minimize biomass loss during the start‐up period, the organic loading rate should be increased only when 75 –80% of the COD fed has been transformed into methane within the design hydraulic retention time. © 2001 Society of Chemical Industry |
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Keywords: | anaerobic digestion anaerobic sequencing batch reactor slaughterhouse wastewater start‐up temperature |
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