A novel three-stage bioreactor for the effective detoxification of sodium dodecyl sulphate from wastewater

Anionic surfactants like sodium dodecyl sulphate (SDS), due to its extensive disposal to water bodies cause detrimental effects to the ecosystem. Among the various attempts to reduce the after effects of these toxicants, microbial induced bioremediation serves as a promising strategy. The current study aimed to develop a three stage bioreactor to remediate anionic surfactants in wastewater using effective bacterial isolates. Screening of effective SDS biodegraders led to isolation of Pseudomonas aeruginosa (MTCC 10311). Treatment of synthetic effluent with an immobilized packed bed reactor at a flow rate of 5 mL h^-1 resulted in 81 ± 2% SDS eliminations and 70 ± 1% reduction in chemical oxygen demand (COD) in five cycles (6 h per cycle). The hydraulic retention time of the reactor was found to be 6 h. Combinatorial usage of a three stage bioreactor, involving aeration, adsorption with low cost scrap rubber granules and treatment with immobilized Pseudomonas aeruginosa, successfully reduced SDS concentrations and COD of wastewater to 99.8 ± 0.1% and 99 ± 1%, respectively, in 18 h by continuous treatment. Half-life of the three stage bioreactor was 72 h. In addition to reducing the surfactant concentrations, this novel bioreactor could resolve the surfactant associated foaming problems in treatment plants, which make it more unique.