The Role Of Extracellular Polymeric Substances Played In Phosphorus Removal Process Of A Marine Strain Shewanella Sp.

Phosphorus is one of the most important element of organisms and one of the essential nutrients of microbes.Nowadays,activated sludge is the most used biological phosphorus removal method.However,the activated sludge required the alternative anaerobic-aerobic conditions to realize ideal phosphorus removal performance.With the developing of industry,the exploit of the natural phosphorus miners increasing.Therefore,to recovery phosphorus from wastewater is a meaningful way to alleviating the shortage of natural phosphorus resource.It had been reported that extracellular polymeric substances played a significant role in biological removal method through adsorption or metal phosphate precipitation.At the same time,extracellular polymeric substances could also remove other pollutants such as heavy metals by adsorption.Therefore,exploring the detailed mechanism of extracellular polymeric substances on phosphorus removal is of actual meaning to seek new pathway on phosphorus removal.On the basis of previous study on phosphorus removal mechanism of a deep sea aerobic phosphorus removal strain CF8-6,the main aim of this study was to investigate the specific role of extracellular polymeric substances on phosphorus removal by CF8-6.The main contents were as follows:Firstly,the phosphorus removal efficiency of CF8-6 in different kinds of wastewater was investigated.The results indicated that in all wastewater selected in the study the phosphorus removal efficiency was above 90%and could satisfied the discharging standard with an initial phosphorus concentration of 10 mg/L.The strain could absorb approximately 12 mg/L phosphorus in synthetic seawater flushing toilet wastewater.Thus,the strain had the application potential in actual wastewater treatment.Then,the effects of environmental factors on the role extracellular polymeric substances played in phosphorus removal were investigated.The results showed that CF8-6 had a wild adaptability to environment.It could grow well and removal phosphorus efficiently at the range of temperature 10-30 ?,pH 5-9,salinity 1-7%rotation speed 150-250 rpm.Finally,the specific mechanism of extracellular polymeric substances played on phosphorus removal was explored by investigation of simultaneous removal chemical oxygen demand,total nitrogen and phosphorus and the effect of metal cations on phosphorus removal.Moreover,the speculated mechanism of extracellular polymeric substances played on phosphorus removal was further confirmed by morphology and elemental characterization methods.The results showed that the concentration of metal cations had little effects on the role extracellular polymeric substances played on phosphorus removal.Therefore,the mechanism of biological induced metal phosphorus precipitation was excluded.The elemental characterization of bacterial cell proved that the capture of phosphorus and formation of extracellular phospholipid nanoparticles was the main pathway of extracellular polymeric substances to removal phosphorus.Phosphorus in nanoparticles was mainly linked with polysaccharides.The investigation of phosphorus removal performance of CF8-6 showed the application potential of the strain on actual in actual wastewater treatment system.The exploration of detailed information on phosphorus removal mechanism of extracellular polymeric substances provided a new orientation to biological phosphorus removal method and reference signification on the phosphorus species in marine sediment and investigation of marine phosphorus recycling.