Effect And Mechanism Of Gasification Phosphorus Removal In Facultative MBR

With the accelerating process of urbanization in our country,the industrial and agricultural production levels have rapidly risen,and a large amount of domestic sewage,industrial sewage and agricultural water have been discharged.If the high concentration of phosphorus in sewage water is discharged to the water body without any sewage treatment,it will cause the eutrophication of the water body,resulting in the deterioration of the water quality and the destruction of the balance of aquatic ecology,which seriously threaten the natural environment of the society and the economy and development.The traditional sewage biological phosphorus removal achieved the removal effect through the action of PAOs mainly,and had the advantages of low operation energy consumption,high phosphorus removal efficiency,no chemical sludge generation,etc.However,the method can only achieve phosphorus removal throught phosphorus-rich sludge emissions,the higher the rate of phosphorus removal,the more phosphorus-rich sludge emissions,and the more serious environment secondary pollution.Under the actual situation of the increasingly serious phosphorus pollution,it is a major objective and urgent task in the field of wastewater biological treatment to reduce the costs of operating and investment,increase the phosphorus removal efficiency and reduce the secondary pollution of phosphorous-rich sludge,and at the same time it is also the inevitable trend and research direction to the future development of water environmental protection in China.With the development of analytical conditions and techniques,phosphine(PH3)has been gradually recognized as a ubiquitous trace substance in the environment and it is generally accepted that PH3 can be produced by microbial reduction.This new phosphorus removal pathway converts phosphate to gaseous PH3 by microbial action,no phosphorus-rich sludge emission,eliminates the problem of phosphorus-rich sludge treatment caused by the traditional phosphorus removal method,avoids secondary pollution and improves theutilization of phosphorus resources.Based on this,Facultative Membrane Biological Reactor(FMBR)without excess sludge discharge is adopted,high-concentration organic phosphorus-rich sewage is taken as research object,a new phosphorous removal technology based on facultative phosphate reduction is proposed in this study.This paper solves the bottleneck problem of traditional biological phosphorus removal technology,provides theoretical and technical support for the development of new phosphorus removal technology based on phosphate bioreduction.In this experiment,a FMBR system was successfully constructed without residual sludge discharge by a step-by-step upgrade of COD load.The removal efficiency of organic compounds and phosphorus in the reactor was gradually increased during the start-up phase.COD and TP were removed above 92%and 45%respectively at the end of 30 days,and the activity of the strain was high and the system was stable.The reactor was gradually detected the formation of phosphine during the formal operation stage,and COD and TP were removed well at this time,COD removal rate can reach 92.09%?94.49%,TP removal rate can reach 48.66%?50.74%.Scanning electron microscopy(SEM)showed good strain traits.In this paper,the effects of different influencing factors on the phosphine production and phosphorus morphological changes were studied,including the inoculate sludgeon,carbon source,organic phosphorus source,pH value and DO concentration.The results showed that:the chicken manure inoculation sludge could promote the transformation of phosphorus form,accelerat the process of facultative phosphate reduction and the production of phosphine;carbon source was as the electron donor of phosphate reduction system,and provided adequate energy,material and reducing power for the microorganism whose reduction was stronger,made the phosphate-reducing bacteria becoming the predominant species,promoted the transformation of the phosphorus form,so as to improve the yield of the phosphine;the phosphate microorganism under the facultative condition was more effective in using the inorganic phosphate and could promote the transformation of phosphorus forms and the production of phosphine;pH = 8.0 was the optimum pH value for the growth of facultative phosphate-reduced microorganisms,which enhanced the activity of microorganisms and proliferated in a large amount,promoted the transformation of phosphorus forms and the production of phosphine;the effect of DO on the change of phosphorus forms in sludge was mainly the effect of appropriate environmental conditions on the growth and development of the facultative microbial cells,thus influencing the ability of internal phosphorus transformation and affecting the process of phosphate reduction and the production of phosphine.The results of phosphorus balance study on the FMBR system with no residual sludge discharged after 30 days of operation showed that the removal of exogenous phosphorus was 227.6 mg per day and the total system lost 2333.13 mg,the total phosphine production is about 578.95 mg/L,which is about 33%of the system phosphorus loss.After 30 days during the start-up phase in the FMBR reactor without excess sludge,the results of phosphorus form transformation indicated that the transformation pathway of phosphorus forms may be Org-P?NaOH-P ? HCl-P ? NaOH-P ? BD-P? H2O-P.After 30 days in the formal operation stage in the reactor,the results of the study on transformation of phosphorus showed that the transformation pathway of phosphorus could be Org-P ? NaOH85-P ? HCl-P? NaOH-P ??BD-P ? H2O-P.The intermediate process of phosphate reduction may be H2PO4-? HPO32-?H2PO2 ? P4? PH3.The transformation of phosphorus in the phosphate reduction system may be:C6H606+H2PO4-+H+ ? CH3COCOOH + 3HC03-+PH3+H2O;C6H6O6 + H2PO4-+H+?6HCO3-+ PH3+H2O?Phosphate biological reduction dephosphorization technology used in high-phosphorus sewage treatment,the role of microorganisms reducing the phosphate to PH3,can save phosphorus source.Thus,the development of efficient and economical new phosphate bioreductive phosphorus removal technology will open up a new way for urban sewage treatment,has important practical significance and good prospects for development and application,will open up new avenues for biological phosphorus removal.