抄録
High-concentration industrial molasses wastewater treatment was examined using biological reactors coupled with physicochemical filtration membranes. The biological processes combined two mesophilic upflow anaerobic sludge blanket (UASB) reactors, a multi-stage upflow anaerobic sludge blanket (MS)-UASB, and a regular UASB for primary anaerobic pre-organic removal, and a downflow hanging sponge (DHS) reactor, equipped with polyurethane sponge media for post-aerobic treatment. Concentrated blackstrap molasses was diluted [12,000 - 1,500 mg of chemical oxygen demand (COD)/L] with organic loading rate (OLR) of 4.5 - 57.7 kg-COD/m3/d (MS-UASB), 2.3 - 34.7 kg-COD/m3/d (UASB), and 0.2 - 6.0 kg-COD/m3/d (DHS). A 1:1.3 recirculation ratio within the MS-UASB was evaluated at different influent concentrations for COD, biogas (CH4) production, and nitrogen, phosphate, and color removal. The average total organic COD removal was over 92% with and without recirculation. A total of 150 NL/d of biogas with 64 - 75% methane content was collected at the maximum loading rate and influent concentration. Ammonia was reduced from 30 mg-N/L to 5 mg-N/L in the DHS reactor. The dark influent could not be reduced biologically; however, ultrafiltration and nanofiltration removed 98% of the color.
