A Study Of Low-polluted Water Treatment With Biological Contact Oxidation Technology

Along with the social economic improvement of living standards, people’s demand for the quality of different kind of water is higher and higher, so a lot of research for low-polluted water treatment have been made.In this study, using biological contact oxidation technology to purify low-polluted water from campus river, set up different biological stuffing density, different biological stuffing arrangement form, including ditch A, ditch B which stuffing is equally distributed, the difference is the density of ditch A is48m/m3, ditch B is24m/m3, ditch C filling density is also24m/m3, but the arrangement locates side by side.Experimental study include the formation of bio-film naturally; Each ditch’s pollutant removal rate under different hydraulic retention time; Each ditch’s pollutant removal rate under different aeration quantity; And by studying different layout density, different arrangement form of their hydrodynamic characteristics, tries to explain the diversity of different ditches on pollutants removal ability; Finally, setting up the pollutant degradation model of COD and NH3-N for different stuffing ditches, and give the introduction to the practical application of this kind biological stuffing in natural campus river.The main draw the following conclusions:(1) The naturally formation of bio-film took about21days, because of the low substrate concentration in the inflow water, the thickness of the bio-film compared with other source of water is thin. Compared with the trailing part of the ditch, the bio-film from the front part is thicker and darker.(2) Through the control of the hydraulic retention time, ditch A leads the potential of pollutant removal, ditch C has the weakest potential of pollutants removal, the potential removal ability of different pollutants as follows:Turbidity> TP> TN> COD> NH3-N. Comprehensive comparison of pollutants removal efficiency under different hydraulic retention time for each ditch and the actual flow rate natural river, the system optimal hydraulic retention time is4h.(3) Through the applying of the aeration oxygenation for stuffing ditch, ditch B has the strongset pollutant removal potential, ditch C’s removal potential is weakest, the potential removal ability of different pollutants as follows:COD> NH3-N> TP> TN. According to pollutants removal efficiency under different aeration rate, as well as the cost of aeration oxygenation. In this system, the optimal aeration rate is10m3/h.(4) Comparing the flow velocity, flow field from ditch A、B、C, it can be seen that with the increase of stuffing density, the disturbance of flow field in the blank layer is more strong; the disturbance of flow field from stuffing arrangement locates side by side (ditch C) is stronger than equally distributed arrangement (ditch B); The flow quantity from blank layer of equally distributed arrangement (ditch B) is more than that from side by side arrangement (ditch C); With the increasing of hydraulic retention time, the percentage of the total flow of the blank layer reduces, makes the stuffing layer has more water contacting, at the same time, the increasing of the hydraulic retention time, also increased the exchange of water body vertically, which is advantageous to the pollutant removal.(5) Through the analysis of the pollutant removal rate with the relationship of hydraulic retention time and the total number of colonies, set up the COD and NH3-N removal models of different ditches. And by using the biological contact oxidation technology on the natural river campus for practical application, the result shows that biological contact oxidation technology has a very good help to clean the low-polluted campus river.