Biodegradation of wastewater organic contaminants using Serratia sp. ISTVKR1 isolated from sewage sludge

• Some xenobiotic organic compounds were detected in effluent of VK STP.
• Serratia sp. strain ISTVKR1 isolated from sludge was used for biodegradation study.
• Almost 12 fold COD reduction was attained after 240 h bacterial treatment.
• Decrease in peak area of complex organic contaminants was observed after treatment.

Wastewater was collected from various stages and sewage sludge was collected from sludge bed of Vasant Kunj sewage treatment plant (VK STP) in the post-monsoon season. The treatment plant is based on extended aeration activated sludge (EAAS) process. Preliminary analysis of the wastewater and sewage sludge samples revealed 11.5 fold reduction in chemical oxygen demand (COD) of wastewater after treatment while GC–MS analysis showed the presence of bisphenol P (RT = 41.63), certain pharmaceuticals, pesticides, and industrial compounds in effluent and sewage sludge, thus indicating the need for further treatments before their discharge into the environment. One indigenous bacterial strain isolated from sewage sludge of VK STP and identified as Serratia sp. ISTVKR1 was used for biodegradation of wastewater contaminants. Preliminary analysis of bacterial treatment culture showed almost 12 fold COD removal after 240 h of treatment while the GC–MS analysis revealed removal of complex organic compounds like phosphoric acid triphenyl ester (RT = 30.017) and 4H-1-benzopyran-4-one, 2-(3,4-dimethoxyphenyl)-3,5-dihydroxy-7-methoxy- (RT = 45.36) and formation of simpler compounds like alcohols and aliphatic hydrocarbons such as 1-heptacosanol (RT = 32.66), docosane (RT = 34.18) and hexadecane (RT = 29.621). Results of the study indicate the efficient removal of wastewater organic contaminants by the isolated Serratia sp. ISTVKR1.