Synchronization Efficient Treatment Of Sewage And Sludge By Hydrolysis Acidification And Denitrification Technology

In the background of increasing sewage collection rate and treatment rate and increasing sludge production in China,the related research on sludge reduction,stabilization and innocuity has been done.In this paper,the production of volatile fatty acids?VFAs?from sewage and sludge by hydrolysis and acidification was studied and applied to denitrification.In the new type of anaerobic baffled reactor,various types of fillers were added to increase the adhesion of microorganism,and the solid residence time?SRT?was completely separated from the hydraulic retention time?HRT?to improve the biomass and the hydrolysis acidification efficiency in the hydrolysis acidification process.In the experiment of hydrolytic acidification of domestic sewage,the maximum influent load of the equipment was 0.628 kgCOD_Cr/?m³·d?at HRT=8 hours.At this time,the removal rate of soluble chemical oxygen demand?SCOD?was 87%,the removal rate of ammonia nitrogen was 27%,and the phosphate removal rate was 15%.In the hydrolytic acidification experiment of mixed sewage and sludge 1:1,the maximum residual sludge hydrolysis acidification load was 3.99 kgCOD_Cr/?m³·d?at HRT=13hours,the sludge reduction rate 37%,SS interception rate 97%,SCOD growth rate27%,ammonia nitrogen growth rate 25%,phosphate growth rate 153%,the effluent SCOD/NH₃-N was 41:1.The effluent has a good biodegradability and can be directly used as denitrification carbon source.In the study of the hydrolytic acidification solution as a denitrifying carbon source,the denitrifying SCOD/NO₃^--N was adjusted to 4,5,6 respectively and the sodium acetate as the control group.The specific denitrifying rates of SCOD/NO₃^--N for 4,5,6 and the control group were 14.9,16.9,17.6 and 21.7 mgN/?gMLVSS?h?respectively.The maximum accumulation of nitrite nitrogen was 9.4,11,11.2 and13.8mg/L.The accumulation of nitrite nitrogen could be quickly reduced when the carbon source was sufficient.After 2 hours of denitrification,the removal rate of nitrate nitrogen is 78%,86%,92%,96%,and the removal rate of COD was 74%.The effluent COD,ammonia nitrogen and total phosphorus met the first grade A standard of“The pollutant discharge standard of urban sewage treatment plant”?GB18918-2002?,so the sludge hydrolysate could be used as a cheap carbon source for denitrification.In the study of simultaneous hydrolytic acidification and denitrification,hydrolytic acidification tank can effectively reduce TN in reflux denitrification solution.When the reflux ratio was 1:2,1:1 and 3:2,the removal rates of SCOD were44.8%,53.4%and 57.6%respectively.The removal rates of TN were 23.4%,35.6%and 54.8%respectively.The hydrolysis and denitrification can be carried out in the same reactor.In the pilot experiment,the kinetic model parameters of hydrolytic acidification were verified.The ratio of feed sludge to sewage was 2:8,HRT was 15 hours,and the maximum excess sludge hydrolysis and acidification load was 2.1 kgCOD_Cr/?m³·d?,the energy consumption of tons of water was 0.1-0.2 yuan,the effluent SCOD/NH₃-N was 12,and the sludge reduced by 60%,which reduced the sludge disposal costs and the pressure of the follow-up processing unit.