| This thesis has chiefly studied treatment effect of Organic compound, Nitrogen and Phosphorus of low concentration domestic sewage and its influence by Wavy Subsurface Flow Wetlands under different hydraulic load, then examined the influence to treatment effect by supplying oxygen to inflow. The research of purifying low concentration domestic sewage by Wavy Subsurface Flow Wetlands with low, middle and high hydraulic load (0.2m3/m2·d, 0.4m3/m2·d, 0.8m3/m2?d ) indicates these results: ⑴ The removal efficiency of COD is good under low, middle and high hydraulic load and average removal rate is 71.0%, 62.3%, 50.1% respectively. The removal efficiency of TP is not high under low, middle and high hydraulic load, average removal rate is 31.7%, 23.6%, 15.3% respectively. The removal efficiency of NH3-N is low under low, middle and high hydraulic load, average removal rate is 15.9%, 11.7%和 9.9% respectively. The removal efficiency of TN is low under low, middle and high hydraulic load, average removal rate is 15.9%, 11.7% and 9.9% respectively. ⑵ With the augment of hydraulic load, the removal efficiency of COD and TP is decline. But the removal efficiency of NH3-N and TN is invariability nearly. ⑶ The removal effect to Nitrogen and Phosphorus is low because of anaerobic environment of wetlands system. At the base of former research, the experiment of supplying oxygen to inflow under 0.4m3/m2?d hydraulic load indicates these results: ⑴ The effect of oxygen recovery is unconspicuous by supplying oxygen to inflow. ⑵ After supplying oxygen to inflow, the removal efficiency of COD is lower than original. Average removal rate is 49%. The removal efficiency of TP is higher than original. Average removal rate is 34.9%. The removal effect of NH3-N is better appreciably than original. Average removal rate is 21.73%,but treatment effect is not still perfect. The removal efficiency of TN is almost as same as original sewage. Average removal rate is 10.59%. Above-mentioned experiment shows that the effect of oxygen recovery is of a sortin constructed wetlands without plant and plant plays an important action during thecourse of wastewater treatment. For further exerting the action of plant and enhancing,the technology of constructed wetland the technology of the choice, implantation andreasonable arrangement should be primarily developed. |
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