Effect Of Anionic Surfactant (SDBS) On Anaerobic Digestion Of Waste Activated Sludge

Recently,people concern more about the issue of waste activated sludge?WAS?disposal.Anionic surfactant and WAS has became a research hotspot.SDBS is a kind of anionic surfactants and currently widely used in the world.It is toxic to animal and plant and has a property of persistence,so it can accumulate in organisms easily.In general,amount of SDBS reaches 50 mg?L^-11 because it always accumulation in sewage treatment plant.However,we have little knowledge about how SDBS affect anaerobic digestion in the long-term.In this study,an experiment of anaerobic digestion of WAS were conducted under batch test and continuous experimental conditions.We compared gases production and physicochemical properties of anaerobic digestion effluent from two anaerobic systems,and observed SDBS degredation over time.By using the the 3D-EEM analysis of anaerobic sludge extracellular polymers?EPS?,the mechanism of anaerobic sludge on SDBS toxicity was revealed.We also clarified the effect of SDSB toxicity on microbial in anaerobic digestion through microbial community structure.This study aims to provide a theoretical basis for the engineering application of anaerobic digestion of WAS containing SDBS.The results of this study were shown below:?1?In the batch experiment,cumulative methane production decreased with the increase of SDBS.In the continuous experiment,we finished the domestication of the fermenting microorganisms by increasing SDBS to 200 mg?L^-1.Tolerance of microorganisms to SDBS stress was improved in this process.In the continuous experiment,the biological removal rate of SDBS decreased with the increase of SDBS,and the SDBS was mainly adsorbed in the solid phase.?2?In continuous experiment,microbes secreted the most EPS protein when SDBS was200 mg?L^-1.EPS significantly decreased when SDBS was 500 mg?L^-1.At this time,EPS transformed from bound state to slime state,anaerobic system deteriorated.This phenomenon can be a warning of indicator of system abnormalities.?3?SDBS lead to a decrease in the diversity and abundance of bacteria.Bacillus can degrading more SDBS when SDBS concentration was lower.When SDBS was 200 mg?L^-1,Sphingomonas proliferated fast,and EPS increased.When SDBS was 500 mg?L^-1,Sphingomonas proliferation was inhibited,EPS protection barrier disappeared.