Enhancement of anaerobic degradation of sludge biomass through surfactant-assisted bacterial hydrolysis

• 0.03 g/g SS of SDS disrupt flocs and enhance sludge enzyme activity.
• Suspended solids reduction was enhanced in deflocculated sludge of about 27%.
• Kinetic appraisal shows that rate was two times higher in deflocculated sludge.
• Surfactant-mediated bacterial pretreatment enhances biogas production potential.
• Biogas production was higher in deflocculated sludge than the flocculated sludge.

In the present paper, the study focuses on the effects of sodium dodecyl sulfate (SDS) surfactant on the release of extracellular polymeric substance (EPS) followed by pretreatment with a thermophilic protease-secreting bacterial strain on WAS (waste activated sludge). This in turn enhanced the subsequent anaerobic biodegradability. The extracellular polymeric substances were released using SDS (0.03 g/g SS of dosage) to stimulate the bacterial pretreatment. The thermophilic bacterial pretreatment results indicated that deflocculated (EPS released with SDS and pretreated with bacteria) sludge showed higher Suspended Solids (SS) reduction of about 27% and Chemical Oxygen Demand (COD) solubilization of about 24%, whereas flocculated (pretreated with bacteria alone) showed SS reduction of about 18% and COD solubilization of about 16%. The biogas production potential of deflocculated, flocculated, and raw (untreated) samples was found to be 2.5211 L/(gVS), 1.7677 L/(gVS), and 0.6140 L/(gVS), respectively. As a result, the EPS release followed by disintegration of sludge by bacteria enhanced the biogas production.

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