Iron And Decayed Wood Fillers Bio-filter Parameter Optimization

Lake water, slightly polluted river water and other micro-polluted water and urban secondary effluent C/N ratio is generally low, lack of carbon source often become limiting factors of nitrogen removal process.Adopted iron and decayed wood assembl-ed f illers anaerobic biological filter for sewage treatment,has advantages such as natural abun dance, low cost, simple structure, and easy operation, etc. However, the operating parameters and the mechanism of this process is not yet clear, and in the actual operation there are problems such as packing volume is too large and filter easily blocked, etc. In this study, by optimizing the iron and decayed wood filler reactor process parameters,improving packing structure, make the reactor under conditions of low carbon can still further reduce the content of organic matter, nitrogen and phosphorus in water, provide the basis for further test and practical operation. The main contents and conclusions are as follows:(1)Study carbon release performance of the decayed wood, and its denitrogenation effect as a carbon source. Adopt two-stage dynamic fitting method, establish parameter equation for the COD concentration released by decayed wood versus time, thus quickly evaluate the carbon release performance of decayed wood. Using intermittent denitrification experiments, through adding nutrient solution and denitrifying sludge,analysis the denitrification effect of decayed wood and the change of COD. Research and analysis concluded that decayed wood can provide long-term stability microbial carbon source for microorganism and has good long-term effects of nitrate removal.(2)Study the factors influencing iron and decayed wood assembled fillers treat simulated wastewater and the optimal reaction conditions. By orthogonal experiment and single factor experiments, controlling different influent p H, reaction time, iron dosage and filler ratio, and test the COD, TP, NO3--N and NH4+-N concentration of the supernatant after reaction, to examine the influence of different reaction conditions on the experimental results. Research and analysis concluded that the primary and secondary relationships of various factors on nitrogen and phosphorus treatment effect is : p H> iron dosage> iron-carbon mass ratio> reaction time, and get a set of optimum reactionconditions. The experiment of the best conditions in real wastewater concluded that iron and decayed wood micro-electrolysis can significantly improve the biodegradability of wastewater.(3)Study the the best packing structure, running effect and influencing factors of the iron and decayed wood fillers biofilter. Continuous operation the reaction column without adjusting p H, study the effect of experimental results on different fillers structure, water flow rate and influent nitrate concentration, and examine the along and effluent NO3--N,NO2--N and NH4+-N concentrations changes of the reaction column, and combined with theory analysis NO3--N removal kinetics. Research and analysis concluded that use upper and lower filling iron, the middle layer filled with decayed wood way of filling get relatively better efftct, effluent nitrite nitrogen and ammonia concentration is proportional to the concentration of water flow rate and influent nitrate concentration. NO3--N removal was maintained above 75%, and after zeolite adsorption layer, the final effluent NH4+-N concentrations is less than 5 mg / L. Under the experimental conditions, NO3--N removal kinetic equation is, the kinetic constant K value of 2.445.