The Characteristics Of Sedimentation And Discharge Of Pollutants And Substrate Flow By Biochemical Activities In Sewage Network

In order to investigate the change of sewage treatment plant influent by migration of pollutants in sewer between sewage and sediment and biochemical metabolism,by controlling the velocity of sewage in a sewer pilot-scale system,the variation of pollutants concentration of sewage and sediment was researched on condition of different sewage flow velocity.And according to the model of pollutants transformation,the characteristics of sedimentation and discharge of pollutants between sewage and sediment was studied.To investigate organic pollutant transformation through biochemical metabolism by analyzing the microorganism in sewer and calculating the substrate flow,the change of sewage quality by bioreaction was researched.The study could provide the theoretical basis of predicting inflow sewage quality of wastewater treatment plant and steady operation of sewage networkAccording to the starting speed equation,which describing the particulate pollutant washed by sewage,0.3m/s was verified as the starting speed for particulate pollutant suspending from sedimentation to sewage.Through the controlling of sedimentation and sewage biochemical environment,pollutant sedimentation,suspending,bioreaction in sewage and sedimentation,the 4 kinds of transformation of pollutants in sewer was built.With the measurement of TCOD ? TN ? TP of sedimentation and sewage,the result showed that 1)when the sewage velocity was less than 0.3m/s,the change of sewage quality was decided by sedimentation and bioreaction;2)when the sewage velocity was greater than 0.3m/s,particulate pollutant was starting to suspend,but sewage quality was decided by sedimentation and bioreaction,too.3)when the sewage velocity was greater than 0.6m/s,sewage quality was decided by pollutant suspending.For the further study of sewage quality change by the bioreaction,through the analyzing of microorganism distribution in sedimentation by High-throughput sequencing,the result showed that methanogens,denitrifying bacteria and sulfate reduction bacteria was the main bacteria which consuming the organic substrate.With the concentrate of organic pollutant,nitrogen pollutant and sulfate,the result suggested that the main pathway to remove the organic pollutant in the sewer system was methane generation,denitrification and sulfate degradation,consuming 32.51mg/L?8.04mg/L and 6.41mg/L organic pollutant,respectively.The 3 kinds of pathway occupied 68.01% of the variation of concentrate of organic pollutant by bioreactions.Therefore,methane generation,denitrification and sulfate degradation were main bioreactions which affect the biodegradability of sewage.