Article ID Journal Published Year Pages File Type
17902 Enzyme and Microbial Technology 2007 10 Pages PDF
Abstract

Dairy wastewater was evaluated for biological hydrogen (H2) production in conjugation with wastewater treatment in a suspended growth sequencing batch reactor (AnSBR) employing sequentially pretreated [heat-shock (100 °C, 2 h) and acid (pH 3.0, 24 h)] mixed consortia. The bioreactor was operated at mesophilic (room) temperature (28 ± 2 °C) under acidophilic conditions (pH 6.0) with a total cycle period of 24 h consisting of FILL (15 min), REACT (23 h), SETTLE (30 min), and DECANT (15 min) phases at three different organic loading rates (OLR) of 2.4, 3.5, and 4.7 Kg COD/m3-day, respectively. H2 evolution rate differed significantly with the substrate/OLR of wastewater used as substrate [OLR 2.4 Kg COD/m3-day - volumetric H2 production rate: 0.3683 mmol H2/m3-min; specific H2 production rate: 0.0184 mmol H2/min-g CODL; OLR 3.5 Kg COD/m3-day - volumetric H2 production rate: 1.105 mmol H2/m3-min; specific H2 production rate: 0.0245 mmol H2/min-g CODL and OLR 4.7 Kg COD/m3-day - volumetric H2 production rate: 0.7367 mmol H2/m3-min; specific H2 production rate: 0.0107 mmol H2/min-g CODL]. Substrate (COD) removal efficiency of 64.7 (substrate degradation rate (SDR): 1.577 Kg COD/m3-day), 60 (SDR: 3.168 Kg COD/m3-day), and 50% (SDR-3.2 Kg COD/m3-day), respectively, was observed at operating OLR of 2.4, 3.5, and 4.7 Kg COD/m3-day, respectively. The system showed rapid stabilization tendency (2.4 Kg COD/m3-day: 39 days; 3.5 Kg COD/m3-day: 14 days; 4.7 Kg COD/m3-day: 24 days) with respect to H2 generation and COD reduction. A surge in pH values from 5.8 to 4.5 (2.4 Kg COD/m3-day), 5.82 to 4.62 (3.5 Kg COD/m3-day), and 6.28 to 4.56 (4.7 Kg COD/m3-day) was observed during stabilized phase of operation.

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