Experimental Study On Modified Non-Woven Fabric-Cyclic Activated Sludge System For Ship Domestic Sewage Treatment

At present,the widely used Membrane Bio-reactor(MBR)ship sewage treatment technology has many problems,such as high operation cost,high cost of membrane modules,and difficult control of membrane fouling,therefore,it is necessary to develop a new process of ship sewage treatment with low cost,high efficiency and stable effluent.In this study,the modified non-woven CASS process(Modified Non-woven Fabric-Cyclic Activated Sludge System)was used to treat ship sewage,through the hydrophilic modification of low-priced non-woven fabrics,the problem of membrane pollution and high cost of membrane components is overcome.At the same time,the CASS process is used to reduce the operating cost and improve the impact resistance.By comparing the properties of the modified film,the best modification parameters are explored in this experiment.Under the best operating conditions,the modified non-woven CASS process was started and the treatment efficiency was investigated.Surface coating method was used to prepare modified nonwoven fabric with glutaraldehyde(GA)crosslinked polyvinyl alcohol(PVA).By comparing the pure water flux and the adsorption amount of albumin from bovine serum(BSA)of modified non-woven fabric under different parameters,the best modification parameters are determined.The concentration of PVA is 0.6wt%,the concentration of GA is 2.0wt%,the coating time is 60min,the heat treatment time is 60min,and the heat treatment temperature is 60?.Under this parameter,the flux of pure water decreased from 55876.33 L/h·m~2 to50437.64 L/h·m~2,the adsorption amount of BSA decreased from 275.53mg/m~2 to 36.75mg/m~2 after the modification of non-woven fabric.In order to explore the maximum treatment potential of CASS technology for ship sewage,first start the CASS reactor to investigate the optimal operating conditions.In order to explore the maximum treatment potential of CASS technology for ship domestic sewage,start the CASS reactor first.After the culture and acclimation of 18d,the reactor is running steadily.The optimum operating parameters of the CASS process are obtained by monitoring the water quality.The operation cycle time is 8h,aeration time is4h,and aeration strength is 0.4m ~3/h.Under this parameter,the CASS process was applied,and the removal efficiency of pollutants in water was:the average removal rate of CODCrwas 96.46%,the average removal rate of ammonia nitrogen was 94.82%,the total nitrogen removal rate was 83.03%,and the total phosphorus removal rate was 95.14%.It is satisfied and much higher than the current discharge standard of ship sewage.The modified non-woven membrane module was applied to the CASS process.Two non-woven CASS processes were launched and two cleaning cycles were run continuously.The test results showed that after adding membrane modules,the water quality of the effluent increased further.Before the modification of modified non-woven fabric,the removal rate of CODCr was improved and the effect of nitrogen and phosphorus removal was guaranteed.The decrease rate of pure water flux in the modified non-woven fabric is slower,and the flux can be recovered to 90.54%of the original flux after physical cleaning.The micromorphology of the membrane surface was detected by scanning electron microscopy(SEM)to reveal that the non woven fabric modified by PVA enhanced the surface evenness of the membrane and improved the pollution resistance of the membrane.