Process Optimization And Performance Of A PAC-DMBR Hybrid System For Wastewater Treatment

Aiming at the problems of high cost of mudules and high spending of running and maintenances for membrane bioreactor reactor(MBR),the experimental was study on the sewage treatment process based on low cost and low energy consumption dynamic membrane filtration technology.In the experiment,different types of membrane modules were selected and used in dynamic membrane bioreactor(DMBR)to compare the effects of dynamic membrane filtration and sewage treatment.Then powdered activated carbon(PAC)was added to the DMBR to study the effect of different PAC dosage on the performance of PAC-DMBR under long-term operating conditions,so as to provide reference for the practical application of PAC-DMBR process.First,for the problem of relaxation of membrne substrate during long-term operation,different types of membrane modules were developed using different supporting material(1# membrane module developed with stainless steel mesh(200mesh),2# membrane module with 200 nylon mesh(200 mesh),3#nylon mesh plus stainless steel(200 mesh)),applied to the DMBR for the comparative study of the dynamic membrane filtration performance and sewage treatment effect.The results showed that the module made of nylon mesh plus stainless steel showed the highest stable flux((80-105L/(m2·h))and operational period(3d)and the treatment performance of different modules was quite similar.Then,from the view of strengthening the formation of dynamic membrane and the removal of pollutants,detecting the different pore size modules(200-500mesh)under1g/L PAC and the module(200 mesh)under different PAC dosage(0.5-3g/L)s' effection on the performance of dynamic membrane bioreactor.It was found that the membranemodule with 200 mesh has a better performance,and 1g/L was the best additive quantity,as the flux increased and turbidity fall rapidly(below 1NTU within 30min),and PAC-DMBR showed better performance compared with DMBR as the removal efficiency of COD,NH4+-N,TP and UV254 were all increased.Finally,three dynamic membrane bioreactors(DMBR)with the dosages of powdered activated carbon(PAC)in the bioreactors of 0,1,3g/L,respectively,were developed and operated parallel to study the effect of dosing PAC on the wastewater filtration performance,sludge properties and treatment effects in the long-term operational PAC-DMBRs.It was found that by dosing PAC,it could enhance the treatment performance of PAC-DMBRs as the removal efficiencies of COD,ammonia,TP,UV254 and color all increased.Through the long-term operation of three reactors,it was found the dosage of 3g/L PAC showed the best operation performance,as the flux increased,the operation period was extended,the turbidity declined rapidly(below1NTU within 30min)and better quality of effluent was achieved.Analysis suggested that dosing PAC could enhance the characteristics of mixed liquor of sludge,promote the formation process and changes in the structure of DM layer.At the same time it was measured that after PAC addition,the size of the sludge flocs increased,sludge settling ability was better,the concentrations of extracellular polymeric compounds(EPS)were lower and the specific oxygen utilization rate(SOUR)of the activated sludge slightly improved.