Flow Carbon Electrode For Controlling Salinity Accumulation In Anaerobic Osmosis Membrane Bioreactor

Wastewater is rich in organic matter,and the recovery of biomass energy is of great significance for solving water pollution and energy crisis.Anaerobic osmosis membrane bioreactor（AnOMBR）with osmotic pressure as the only driving force is coupled with a forward osmosis membrane with excellent interception effect,which can effectively trap microorganisms and dissolved methane in the effluent,and recover the biomass energy it is good.However,in the process of using seawater or concentrated brine as the drawing liquid,the forward osmosis membrane is not strictly a non-porous membrane,which will inevitably cause the reverse diffusion of the solute of the drawing liquid,which is easy to cause the accumulation of salinity on the side of the raw material liquid and make the reactor operate efficiently decline.In order to solve the problem of AnOMBR raw material liquid side salinity accumulation,this paper couples the flow carbon electrode（FE）to control the AnOMBR raw material liquid side salinity accumulation.The research is mainly divided into two aspects:（1）By measuring the water flux and the conductivity of the raw material liquid,the removal rate of COD,ammonia nitrogen and phosphate in the reactor,volatile fatty acids（VFAs）,the polysaccharide and protein concentration in the supernatant of the sludge,and the SEM and EDX of the surface of the contaminated membrane to investigate the operation effect of the reactor after introducing the flowing carbon electrode for desalination.The results show that,compared with the conventional AnOMBR（C-AnOMBR）（9.5 mS/cm）,the desalted AnOMBR（D-AnOMBR）feed solution can achieve a lower salinity（4.2 mS/cm）,the initial water flux decline is alleviated,the removal rate of COD is increased by 6.11%,and the accumulation of NH₄⁺and PO₄^3-in the reactor no longer exists.Compared with the continuous increase of SMP in the C-AnOMBR phase,the SMP in the D-AnOMBR phase first increased and then decomposed and dropped to the initial value,indicating that the effect of sludge salt stress was reduced and the system was more stable.VFAs and pH data also indicate that D-AnOMBR is more conducive to sludge survival.The EDX results show that the content of elements that constitute the inorganic membrane pollution in the D-AnOMBR stage decreases.（2）By measuring the water flux and the conductivity of the raw material liquid,the removal rate of COD,ammonia nitrogen,and phosphate in the reactor,volatile fatty acids（VFAs）,the polysaccharide and protein concentration in the supernatant of the sludge,and the SEM and EDX of the surface of the contaminated membrane to investigate the effect of electrodialysis desalination（E-AnOMBR）on the performance of the reactor,and to compare the improvement of the desalination effect by introducing a flowing carbon electrode on the basis of electrodialysis desalination.The results show that compared with C-AnOMBR（9.5mS/cm）,E-AnOMBR conductivity can be maintained at 4.60 mS/cm,which is lower than D-AnOMBR（4.2 mS/cm）,indicating that the introduction of mobile carbon electrode based on electrodialysis desalination The effect of desalination can be improved.In addition,the removal rate of COD increased,NH₄⁺and PO₄^3-no longer accumulated,SMP,VFAs,pH and EDX results also showed that D-AnOMBR and E-AnOMBR performed better than C-AnOMBR after desalting.