Author/Authors :
Daniel I. Masse، نويسنده , , Lucie Masse، نويسنده ,
Abstract :
High strength slaughterhouse wastewater was treated in four 42 l anaerobic sequencing batch reactors (ASBRs) operated at 30°C, 25°C and 20°C. The wastewater contained between 30% and 53% of its chemical oxygen demand (COD) as suspended solids (SS). The ASBRs could easily support volumetric organic loading rates (OLRs) of 4.93, 2.94 and 2.75kg/m3/d (biomass OLRs of 0.44, 0.42 and 0.14 g/g volatile SS (VSS)/d) at 30°C, 25°C and 20°C, respectively. At all operating temperatures, the total COD (TCOD) and soluble COD (SCOD) were reduced by over 92%, while average SS removal varied between 80% and 96%. Over the experimental period, 90.8%, 88.7% and 84.2% of the COD removed was transformed into methane at 30°C, 25°C and 20°C, respectively. The decrease in the conversion of the COD removed into methane as operating temperature was lowered, may be partly explained by a lower degradation of influent SS as temperature was reduced. The reactors showed a high average methanogenic activity of 0.37, 0.34 and 0.12 g CH4-COD/gVSS/d (22.4, 12.7 and 11.8 l/d) at 30°C, 25°C and 20°C, respectively. The average methane content in the biogas increased from 74.7% to 78.2% as temperature was lowered from 30°C to 20°C.
Keywords :
Anaerobic sequencing batch reactor , Slaughterhouse wastewater , anaerobic digestion , Operating temperature