Low-Carbon Source Sewage Efficient And Low-Cost Biochemical Synergistic Phosphorus Removal Technical Research

At present,the low-carbon source of urban sewage is more common.The application of external carbon sources to ensure the removal of phosphorus and nitrogen has become a measure that most sewage plants have to take.Reducing the operating cost of sewage treatment has become a low-carbon source wastewater treatment technology.The problem that needs to be solved.Biological phosphorus removal is achieved by utilizing the aerobic excess phosphorus uptake capacity of polyphosphate bacteria.Previous studies have found that the concentration of phosphate in the solution often appears to be close to zero after aerobic excess phosphorus absorption.This situation indirectly indicates that the biological active phosphorus uptake process is not limited by the equilibrium concentration of the solution.Based on the objective requirements of high-efficiency and low-cost treatment of phosphorus removal from low-carbon source sewage,based on the analysis of the respective advantages of biological phosphorus removal and chemical phosphorus removal,from the perspective of meeting increasingly strict sewage discharge requirements and reducing sewage treatment operation costs,A part of aerobic sludge external carbon source was constructed to strengthen anaerobic phosphorus release,lateral flow chemical dephosphorization,aerobic phosphorus deficiency and enhanced biological active phosphorus uptake.Around the development of this technology,the low-carbon source sewage with COD of 120²13 mg/L and COD/TP of 23.6 was studied.The side-flow phosphorus removal performance of low-carbon source sewage and the low-carbon source sewage enhanced anaerobic phosphorus release were studied.In this paper,the enhanced anaerobic phosphorus release effect of the external circulation aerobic phosphorus-rich sludge in the low-carbon source sewage high-efficiency and low-consumption biochemical phosphorus removal system was studied.Based on the results,the external circulation sludge volume and the corresponding carbon source were designed.Adding amount and discussing the effect of phosphorus removal on low-carbon source sewage,the results show that:?1?The initial MLSS=3.5 g/L of the lateral flow dephosphorization system uses the manually adjusted low-carbon source campus domestic sewage as the treatment influent while adding COD=100 mg/L mixed carbon source in the anaerobic section.In the lateral flow dephosphorization system,anaerobic stage phosphorus-rich wastewater was discharged in three stages at a side stream ratio of 5%,7.5%,and 10%,and the effluent TP concentrations were 0.67,0.08,and 0.06 mg/L,respectively.When the side-flow ratio is 7.5%,the system runs stably,and the TP concentration is lower than 0.01 mg/L,and the ultra-low phosphorus effluent is obtained.The 5%lateral flow ratio is lower than the drainage phosphorus removal,and the effluent cannot reach the standard discharge;The7.5%lateral flow ratio is too high.Excessive drainage and phosphorus removal leads to a decrease in the phosphorus storage capacity of the system,and the activity of the polyphosphate bacteria is affected,and the long-term efficient phosphorus removal effect cannot be maintained.The side-flow dephosphorization technology treated the effluent average TP concentration of 0.07 mg/L,and often can obtain ultra-low phosphorus effluent,better than the traditional biological phosphorus removal effluent TP about 0.25mg/L of phosphorus removal;lateral flow dephosphorization technology The dosage of aluminum salt is only 0.42⁰.85 of traditional biological phosphorus removal,which is lower than traditional biological phosphorus removal.?2?The effects of carbon source species on anaerobic phosphorus release of polyphosphate bacteria were studied.When acetic acid,propionic acid and glucose were used as carbon sources,the phosphorus release rate of the system was 26.73,16.59,6.13mgP/g MLSS,acetic acid.The effect of VFAs with propionic acid as a carbon source is much better than that of non-VFAs as a carbon source.The effect of carbon source addition on the anaerobic phosphorus release of polyphosphate bacteria is found.The rate of phosphorus release in one-time dosing and three-time dosing is basically the same as that in the sludge,and the concentration of glucose added in three times is 23.7%higher than that in the one-time dosing.Adding non-VFAs to the carbon source system is effective,but has no obvious effect on the VFAs.If the influent carbon source is mainly VFAs,the one-time influent is cheaper.Studying the ratio of C/acetic acid to the phosphorus-dissolving bacteria The effect of pure acetic acid,propionic acid/acetic acid content ratio of 0.5,1,2,pure propionic acid five gradients,found that the degradation rate of VFAs increased with the proportion of propionic acid/acetic acid,propionic acid/acetic acid ratio It has little effect on primary phosphorus release,but it will affect the secondary phosphorus release,which will affect the final phosphorus release balance.Degree,the higher the ratio of acetic acid,the higher the equilibrium concentration of phosphorus release,the highest when pure acetic acid is used as the carbon source,and the phosphorus release rate of sludge is up to 26.11 mgP/gMLSS.Therefore,the strengthening of pure acetic acid during one-time dosing The phosphorus release effect is the best and the operation is cheap.?3?Taking the aerobic phosphorus-rich sludge of anaerobic phosphorus release tank as the research object and selecting acetic acid as the carbon source,it is found that the maximum specific gravity of aerobic sludge in the high-efficiency and low-consumption biochemical phosphorus removal system of this low-carbon source sewage.The phosphorus release rate was 26.01 mgP/gMLSS.The aerobic phosphorus-rich sludge of the system reached the minimum carbon source requirement under the maximum phosphorus release rate of the sludge.It was found that the absorption of 1 mg of HAc-COD induced the release of 0.4924 mg P from the molecule.From a point of view,about1 mol of PO₄^3-is released per 1 mol of HAc,and about 26.01 mg of phosphorus can be released per 1 g of phosphorus-rich sludge,while 52.82 mg of HAc-COD is required.In the high-efficiency and low-consumption biochemical synergistic dephosphorization system of low-carbon source sewage,the mainstream SBR system has low carbon source concentration and anaerobic 1h,and the external circulation sludge anaerobic phosphorus release tank has sufficient carbon source for anaerobic 2 h.Under this operating condition,it can be observed.Most of the time,the effluent TP concentration<0.01 mg/L,the realization of ultra-low phosphorus effluent efficient phosphorus removal effect,excessive phosphorus uptake 108.6 mg,much higher than the ordinary sidestream phosphorus removal system of excessive phosphorus uptake.The low-carbon source sewage high-efficiency and low-consumption biochemical synergistic dephosphorization technology treats low-carbon source sewage to achieve ultra-low phosphorus emission of effluent,and can save chemical cost compared with traditional biological phosphorus removal+terminal chemical phosphorus removal technology,compared with common lateral flow Phosphorus-rich wastewater dephosphorization technology can save the external carbon source dosage,and finally achieve high-efficiency and low-cost biochemical synergistic phosphorus removal of low-carbon source sewage.