Experiment Of Nitrogen Removal By Constructed Wetland-ecological Pond Combined System From Polluted Water

Proposing the using of artificial wetland-pond treatment combined with the current waterpollution situation, this article gives some examples of application for constructedwetland-pond treating with polluted water, comparison of different wetland system betweenthe operating parameters and treatment effect of data. Confirming that the artificialwetland-pond technology in micro-polluted water treatment work well by it，s operationeffects. And put forward to some improvement of artificial wetland technology direction, withwhile the artificial wetland development prospects.Subsurface flow constructed wetland consists of posted ecological pond processed asystem in open conditions from November to January of the next year through the winter, theremoval efficiency of this combination system to the nitrogen as the index of wetland. Byusing the orthogonal test method, it researched significant influence of4factors including thehydraulic load of wetland, the ratio of carbon to nitrogen, the intensity of pre-aeration and thedepth of pond on index and found out the optimum condition. And it analyzed variance of theorthogonal experiment results by using SPSS software. The results show that the hydraulicload of wetland, the ratio of carbon to nitrogen, the intensity of pre-aeration has significantlyinfluenced, the effects of various factors on the degree of the total nitrogen and ammonianitrogen removal rate from the combination system in turn as: the hydraulic loaded of wetland> the ratio of carbon to nitrogen> the intensity of pre-aeration> the depth of pond. Theconditions of the highest rate of the total nitrogen and ammonia nitrogen removal from thecombination system are the same as follows: the hydraulic load of wetland is75mm/d, theratio of carbon to nitrogen is6, the pre-aeration ratio of air to water is6and the depth of pondis0.5m. The rate of nitrogen removal from the combination system remained at a high level.The using of artificial wetland constructed wetland pond system device forcontinuous operation under different hydraulic loading is monitoring of campus sewage. Theresults show that the removal rate of COD, TN and NH4+-N decreased with the increasingof hydraulic load (200mm/d with low hydraulic loading,500mm/d with mid-hydraulicloading,1000mm/d with high hydraulic loading) and it all maintained at a high level. Thechange rate of COD with effluent was less than it with inlet in all hydraulic loading, thechange rate with effluent was less than it with inlet of TN in low and mid-hydraulic loadingand NH4+-N in mid and high hydraulic loading; and NO3--N and NO2--N concentration ineach the structures changes a lot, with also showing different trend of change. This shows thatin different hydraulic loadings, the pollutant removal effect is good, the combination system has powerful shock load capability in mid-hydraulic loading. Nitrification andDE-nitrification is the main way for nitrogen removing in the constructed wetland-pondcombination system, and it change approach to play a regulatory role in the stability of waterquality in different load shock.Using the ecological pond-surface flow wetland-horizontal subsurface flowwetland-surface flow wetland-ecological pond in order to build multistage constructedwetland-pond combination system, and continuous operation of the system on treatment ofseverely polluted lake in the appropriate hydraulic load (500mm/L), then monitoring of all thepollutant indexes. The result shows that, in this hydraulic loading the change of COD, TN andNH4+-N in the effluent was smaller than that in inlet, so the combination system treatment ofseverely polluted surface water has powerful shock load capability in this case. At the sametime comparing the data between the multistage combination system treatment of pollutedwater and the same as two-stage combination system，it indicates that under the samehydraulic loading conditions by the concentration of pollutants in water increasedsignificantly, it could maintain or improve the rate of COD, TN and NH4+-N removal bycombination system from polluted water by improving the constructed wetland-pond systemcombination stages. This made a positive attempt for strengthening the efficiency with thetreatment of polluted water by improving the constructed wetland-pond system combinationstages.