Research Of Adding Plant Carbon On Enhanced Nitrogen Removal In Horizontal Subsurface Wetland

In this paper, the problem of low nitrogen removal efficiency of constructed wetland under low carbon and nitrogen ratio were studied. By comparing the selected plant carbon material which is suitable for constructed wetland, the carbon addition location, dosing ratio and hydraulic loading conditions are totally optimized in the test apparatus. The result of the carbon regulating parameter optimization was applied to the constructed wetland, nitrogen removal efficiency was observed in the constructed wetland which was under the control of carbon source, and the feasibility of the carbon source control in constructed wetlands was verified. The scanning electron microscopy and molecular biology techniques were used to analysis the microstates, dominant bacteria and denitrification microbial inside the wetland.(1) Among reed straw, corn cob, sycamore bark, Indus leaves four plants, corn cob in the soaking process released large amounts of organic matter and sustained release ability, corn soaking solution B/C value was 0.35 after 30 days, which has good biochemical ability, simultaneously with the decomposition of corn cob colorless degrees, decomposition was powdered, which would not cause clogging problems, and were suitable as wetland plant plant carbon source.(2) Carbon source control parameter optimization study found that corn cob control investment volume ratio is 1.0%, the adding position should be added at the rear of the wetland, hydraulic loading was adjusted 2.03m3/ m2·d. And this time pilot plant effluent COD value without deterioration, and total nitrogen average removal rate were more than 45%.(3) The results of the constructed wetland pilot plant were showed as follows: the average removal rate of COD in the wetland without carbon source was 38.71% and the total nitrogen average removal rate was 34.24%, the average removal rate of COD in carbon source wetland was 38.52%, total nitrogen average removal rate reached 70.55%. Undering the premise of reasonable regulation and control, plus plant carbon source can effectively improve the artificial wetland nitrogen removal efficiency.(4) The matrix internal electron microscope on the artificial wetland system were used to scan found attached to the surface of a large number of short bacilli microbes, sessile algae, plankton, purify water have on artificial wetland; molecular biology detection results showed that the dominant bacteria within the artificial wetland system about 10 genera. The nitrogen removal bacteria including Pseudomonas sp. of Pseudomonas putida, Pseudomonas fluorescens; Acinetobacter junii in Acinetobacter sp.; Serratia marcescens in Serratia sp.; Brevundimonas diminuta in Brevundimonas sp.; and the effect of nitrogen removal in constructed wetland was verified from the point of view of molecular biology.