LAUSR

This study provides extensive information about oily wastewater treatment in aerobic granular reactors (AGR) using three different inoculums from sewage, refinery and brewery. Initially, sodium acetate was used for granule formation while AGR with brewery inoculum had maximum granule size (5.44 ± 0.05 mm) and extracellular polymeric substances (EPS: 471.22 ± 2.0 mg/g VSS). But, during emulsified diesel exposure, refinery sludge granules achieved maximum granule size of 3.49 ± 0.01 mm and EPS of 204.85 ± 2.01 mg/g VSS with maximum 67.39 ± 0.15% oil removal efficiency. AGRs achieved 99.9 ± 0.05% chemical oxygen demand (COD) and 91.67 ± 0.14% ammonia nitrogen (NH4+-N) removal efficiencies. Refinery granules remained stable at maximum 310 ± 10 mg/L diesel concentration whereas, the stability thresholds for sewage and brewery granules were 170 ± 15 and 250 ± 10 mg/L, respectively. Brevibacterium paucivorans strain SG001, Micrococcus aloeverae strain SG002 and Staphylococcus hominis strain SG003 were identified as the major pollutant degraders isolated from sewage, refinery and brewery sludge. Micrococcus aloeverae strain SG002 exhibited maximum pollutant removal efficiencies (COD: 99.9 ± 0.01%, NH4+-N: 99.9 ± 0.01%, oil: 61.34 ± 0.85%) among the three species. Re-addition of sodium acetate restored granule structure and stability.