Study On The Running Effect And Decontamination Mechanism Of The Heat Pump-Subsurface Wetland System

Compared with traditional sewage treatment methods,constructed wetland which has the advantage of convenient in management,low investment and operation cost,better removal efficiency in phosphorus and ammonia has been widely applied both at home and abroad.However,the reduction of treatment effect under cold winter conditions has been the main bottleneck restricting the large-scale application of artificial wetlands in the north.This paper combines artificial wetland technology with the heat pump technology,constructing small subsurface wetland,using the effluent of wastewater treatment plant in Tangshan as water source,studying the effect of artificial wetland on the removal of TN,TP,COD and ammonia as well as the application of heat pump in artificial wetland,obtaining the following conclusions:When HRT=4d,the comprehensive treatment effect achieved the best performance,the average removal rate of TP,TN,ammonia and COD was 99.6%,55.86%,91.99% and 62.49%,respectively.The removal of COD and TN mainly occurred in the anterior and central part of the wetland pool,TP mainly occurred in the anterior part,ammonia nitrogen mainly occurred in the central and posterior part.The removal of nitrogen and phosphorus mainly occurred in the zeolite layer,the slag and gravel layer removal effect was poor;The ground uptake of phosphorus and ammonia by plants were higher than underground,moreover,the absorption amount of nitrogen and phosphorus was not more than 5% in the amount of wetland removal,it was too small to be ignored.Aromatic protein,aromatic protein,dissolved microbial metabolites,rich acid and humic acid were found in the treatment wastewater,and the concentration of organics showed a decreasing trend in the direction of water flow.During the experiment performance,the removal efficiency of TN,COD,TP and ammonia was over 50%?55%?96% and 80%,respectively.As the temperature increased,the processing cost increased,it was more economic and reasonable when the heat pump temperature was setted 35?.