Study On Remediation Technology And Pilot Scale Experiment Of Landscape Ecological Biofilm Water Environment

It is found that the traditional wastewater treatment technology has some disadvantages,such as large land occupation and poor landscape effect.This paper builds a Landscape-Biofilm Ecological Treatment System(LBETS)with small footprint and ornamental landscape to treat rural domestic wastewater and urban contaminated surface water by coupling biofilm and landscape plants ecological treatment process.The absorption of N and P by different emergent plants and the growth of plants were inspected,and the effects of different C/N ratios on the treatment efficiency of LBETS and the mathematical model were also studied.A landscape ecological-biofilm pilot system was constructed for contaminated water treatment.The absorption of N and P and the growth status were studied in three kinds of emergent plants: Canna,Iris and Pontederia cordata.The results show that Canna is ahead of the other two plants in terms of plant height,maximum root length and plant biomass,and its removal rates of TN and TP reach 59.40% and 51.71% respectively,higher than those of Iris and Pontederia cordata,indicating that Canna has a better removal efficiency of TN and TP.Therefore,Canna is used as LBETS system plant.The treatment efficiencies of LBETS on the simulated rural domestic wastewater were investigated given different C/N ratios.The results show that when the C/N is 4:1,the average removal rates of NH4+-N,TN and TP are 75.08%,27.16% and 36.84%respectively,and the effluent concentrations are 4.22 mg·L-1,12.46 mg·L-1 and 1.90mg·L-1respectively.The results also show that the average removal rate of CODCr is above 90% and the effluent concentration is less than 15 mg·L-.During the experiment,the plant growth in the reaction system was good.Based on the models of International Water Association,a mathematical model was established to illustrate LBETS's simulation of rural domestic wastewater treatment process.Based on the ASM2 D model,a plant growth kinetics model was added and the LBETS-ASM2 D model was established.Based on the ASM3 model,a biological phosphorus removal model and a plant growth kinetics model were added and the LBETS-ASM3 model was established.The results indicate that the LBETS-ASM2 D model has a lower deviation rate and can better simulate the system's wastewater treatment process.This is because the ASM2 D model is a model in which nitrification-denitrification simultaneously conducts biological phosphorus removal,which can more accurately describe the biological removal kinetics of nitrogen and phosphorus in the system.Based on the study of LBETS,an LBETS pilot system was constructed.Aiming at the characteristics of poor water quality,low water flow and so on in the closed water area of Huaqiao University Xiamen Campus,the pilot experiment was carried out.After operations in different seasons,it shows that in the experimental area,the contents of DO,CODCr,NH4+-N,TN and TP decrease significantly in spring and stay constant in summer,while in the non-experimental area,the indicators decrease in summer but rebound in summer.TN and NH4+-N approach Surface Water Environment Quality Standard(GB3838-2002)? Class standards,with TP,CODCr and NOx--N even reaching IV Class standards,indicating that the pilot system is effective and can be applied to the treatment of rural domestic wastewater and urban contaminated surface water.