Study On The Treatment Of Polluted River By Subsurface Constructed Wetland

Constructed wetland system is a new type of ecological wastewater treatment technology. It is a process with high treatment efficiency, low investment, cheap operational fee, low energy, wild field of application and soon. So, constructed wetland will become a prospect of polluted water treatment methods. However, there is lack of uniform design parameters and methods to build constructed wetland at present. Therefore the construction of constructed wetland is usually based on successful pilot experiment. This article uses the Subsurface constructed Wetland which is efficient processing, and use the river water of university of science and technology of Suzhou to make experimental study. The main content of this study includes: (1) confirming best hydraulic loading and residence time; (2) confirming best combination of stuffing and plant; (3) the study on removal of nitrogen and phosphorus.The test result indicated that: (1)within the scope of experiment, get the best hydraulic loading that is 24 cm3/cm2.d through comparison.under the best hydraulic loading, 24 cm3/cm2, permanganate-index density in the water of the artificial wetland is 3.01-5.95mg/L, removing rate is equally 44.51%;the density of total nitrogen in out-put water is 1.460-3.360mg/L, removing rate is equally 52.99%; the density of ammonia nitrogen in out-put water is 0.099-5.950mg/L, removing rate is equally 63.39%; the density of total phosphorus in out-put water is 0.039-0.172mg/L, removing rate is equally 67.98%; the density of orthophosphate in out-put water is 0.013-0.09mg/L, removing rate is equally 63.88%. (2)within the scope of experiment, get the best combination of stuffing and plant of Subsurface Flow Wetland in medium of experiment that is Typha augustifolia+zeolite+yellow sand+calcium carbonate. (3)Through mensurate, rudely get absorption capacity of reed and Typha augustifolia to the nitrogen and phosphorus. By estimate, the nitrogen content of the stalk and leaf of reed occupy the nitrogen content in the water is 8.34%. the phosphorus content of the stalk and leaf of reed occupy the phosphorus content in the water is 12.18%. the nitrogen content of the leaf of Typha occupy the nitrogen content in the water is 2.96%. the phosphorus content of the leaf of Typha occupy the phosphorus content in the water is 6.97%.(4) The test result indicated that plant harvesting is unimportant, The plant can improve system micro-enviroment and hydrology condition and so can increase nitrogen and phosphorus removal rate.