In Situ Biological Activity And Influencing Factors Of Phosphorus Removal Bacteria In Activated Sludge Aggregates

Micro-electrode is a kind of miniature sensor with small tip,low detection limit,short response time and high precision.It is a study on the mass transfer and degradation of sludge mass inside the water treatment process,kinetic characteristics and microbial in situ.A powerful tool for activity.In order to understand the transformation law of PO₄^3--P in the activated sludge group,the phosphate and ORP microelectrodes were fabricated in a deeper and more intuitive way.The A²/O process and SBR denitrifying phosphorus removal process were studied at the microscopic level.The in-situ biological activity of the phosphate-dissolving bacteria in the activated sludge group and its influencing factors have yielded the following results:?1?A phosphate microelectrode and an ORP microelectrode were prepared by a metal encapsulation method and a low melting point alloy electroplating method,respectively.The electrode tip is less than 25?m,the linear regression coefficient is above 0.99,the response time is less than 65 s,and it has good resistance to external interference,and the microelectrode performance is good.?2?The in-situ biological activities and influencing factors of dephosphorization bacteria in the sludge group of denitrifying phosphorus removal system were investigated by using phosphate,ORP and DO microelectrodes.The results show that:?1?The maximum net volume of phosphorus release rate in the early stage of anaerobic period was 3.29 mg·?cm³·h?^-1,and the rate of phosphorus release was maintained in the range of 0?1600?m.Compared with the early stage,the overall phosphorus release rate decreased,the maximum net volume release rate decreased to1.59 mg·?cm³·h?^-1,and the phosphorus release area was mainly concentrated from 0 to700?m.The net volume of phosphorus uptake in the early stage of hypoxia is large,and the maximum is 1.09 mg·?cm³·h?^-1.In the late stage of anoxic,the net volume phosphorus uptake rate in the range of 0?800?m is maintained at about 0.1mg·?cm³·h?^-1.With the increase of sludge depth,the phosphorus uptake reaction almost stops,and below 1800?m,a"secondary release of phosphorus"phenomenon occurs.?2?The effects of initial COD concentration and initial NO₃^--N concentration on in situ bioactivity of dephosphorization bacteria in sludge groups under anaerobic conditions and anoxic conditions were studied.It was found that the initial COD concentration in the anaerobic section increased from 100 to 350 mg·L^-1,the maximum net volume of phosphorus release rate is from 2 to 3.2 mg·?cm³·h?^-1,and the rapid release of phosphorus is increased from 0 to 800?m to 0 to 1700?m.When the initial NO₃^--N concentration in the anoxic zone was increased from 25 to 50 mg·L^-1,the maximum net volume phosphorus uptake rate was increased from 0.83 to 1.53mg·?cm³·h?^-1,and the fast phosphorus uptake area was 0?600?m increased to 0?1300?m,and the fast phosphorus absorption area extends deep into the sludge.?3?The in-situ biological activities and influencing factors of phosphate-removing bacteria in the sludge group of A²/O process were investigated by using phosphate,ORP and DO microelectrodes.The results are as follows:?1?The phosphorus release reaction mainly occurred in the anaerobic stage,and the maximum net volume release rate was 2.88 mg·?cm³·h?^-1.Although the sludge is continuously released during the anoxic phase,the phosphorus release reaction is weak,and the maximum phosphorus release rate is 0.83 mg·?cm³·h?^-1,and it mainly occurs in the range of 0?500?m.The aerobic front-end phosphorus uptake reaction mainly occurs in the range of 0?1500?m,and the maximum net volume phosphorus uptake rate is 0.29 mg·?cm³·h?^-1.At the end of aerobic stage,the net volume of phosphorus uptake rate is almost zero,and the phosphorus uptake reaction almost stops.?2?The effects of initial NO₃^--N concentration and initial DO concentration on the in-situ bioactivity of dephosphorization bacteria in the sludge group under A²/O process under anoxic conditions and aerobic conditions were studied.It was found that with the NO₃^--N concentration ranged from 4 to 15 mg·L^-1,and the maximum net volume release rate decreased from 0.97 to 0.26 mg·?cm³·h?^-1,showing a gradual decrease.The main phosphorus release area is reduced from 0?800?m to 0?300?m.When the DO concentration in the aerobic section increased from 1 to 4 mg·L^-1,the maximum phosphorus uptake rate increased from 0.07 to 0.31 mg·?cm³·h?^-1,and the fast phosphorus uptake region spread to 0?800?m.When the DO concentration increased to 6 mg·L^-1,the maximum phosphorus uptake rate did not change significantly,and the fast phosphorus uptake area only extended to the depth of the sludge floc by about 300?m.