Nitrogen And Phosphorus Removal Technology In Constructed Wetland

Too much nitrogen and phosphorus compounds into the natural water bodies will not only deteriorate the water quality, but also seriously harm on human health and animal or plant survival. Therefore, the study of nitrogen and phosphorus removal in sewage has become the research topic urgent to carry out.Experiments include three parts:denitrification, phosphorus removal and denitrification kinetics:(1) Studied a wide range of materials both as solid carbon source and biofilm carrier to remove the nitrate in wastewater, examined the impact of biological denitrification in different conditions such as the influent concentration, temperature, the proportion of added carbon,hydraulic retention time, etc. Further optimization the process;(2) Use iron-carbon internal electrolysis wastewater treatment technology on phosphorus, studied the conditions of aeration and without aeration as well as different aeration effectiveness of internal electrolysis phosphorus removal;(3) In order to have a better understanding with the performance of wheat straw, PBS, and PHAs, carried out by Monod equation kinetic analysis were obtained three kinds of carbon sources of nitrate denitrification Monod model.The results show that:(1) Wheat straw as carbon source to remove nitrate nitrogen, the most optimal conditions was temperature of 25℃, hydraulic retention time of 10h, the influent concentration of 30mg/L and straw of 2g; PHAs as carbon source the most optimal conditions was the temperature of 15℃, hydraulic retention time of 30h, the influent concentration of 45mg/L and PHAs of 2g; PBS as a carbon source to remove nitrate nitrogen the most optimal conditions was temperature of 35℃, hydraulic retention time of 30h, the influent nitrate nitrogen concentration of 30mg/L and PBS for 0.5g;(2) The removal rate of phosphorus in the aeration conditions is far higher than under the without aeration conditions, and the bigger aeration the better removal rate of phosphorus;(3) Wheat straw as carbon source, The largest nitrogen nitrate reduction rate Vmax= 0.022 (d-1), nitrate saturation constant Kn=15.69 (mg/L); PBS as carbon source, Vmax=0.037 (d-1), Kn=1.168 (mg/L); PHAs as carbon source, Vmax=0.134 (d-1), Kn=32.24 (mg/L);...