Study On Water Quality Purification System Of Improved Planting Eco-concrete Landscape Slope Bank

Nowadays,a large number of impervious concrete pavement and buildings replace the original land,resulting in a large number of road runoff,carrying a large number of pollutants(such as urban landfill leachate,heavy metals,animal and plant residues)with runoff rainwater into the natural water body,causing pollution.Traditional plant-type ecological concrete has limited ability to remove heavy metals,dissolved organic matter and emerging pollutants.Therefore,red mud and fly ash with good adsorption capacity are selected to replace equal amount of cement,and improved plant-type ecological concrete is prepared.The optimal replacement amount of red mud is 10%.The removal rates of total nitrogen,total phosphorus and ammonia nitrogen are 40.2%,68.55%and 57.45%respectively.The strength is 8.28 MPa,the porosity is 21.4%,the permeability coefficient is 13.11 mm/s,and the pH value is 9.17,which can meet the requirements of plant slope protection and enhance the water purification capacity.Through the further study of water purification capacity of improved plant-type ecological concrete,it is found that the purification effect of three improved plant-type ecological concrete(RFC,RFC-A,RFC-A-P)is better than that of traditional plant-type concrete(TC)on various pollutants(TOC,TN,NH3-N,TP;Cu2+,Zn2+,Pb2+,Cd2+;DCF).In addition,using EEMs-PARAFAC and other analytical methods,it was found that plant-type ecological concrete had better removal effect on DOM protein-like and humic acid-like substances in pavement runoff,and the effluent after treatment showed certain characteristics of fulvic acid-like,indicating that microbial activities were involved in the process of plant-type ecological concrete.Finally,the interaction between the typical pollutants Dissoled Organic Matter(DOM)and Heavy Metal(HM)in pavement runoff was studied.It was found that heavy metal ions(Cu2+,Cd2+,Pb2+)and protein-like substances in DOM samples were liable to occur complexation by two-dimensional synchronous spectroscopy,and the complexation ability of Cu2+,Cd2+with DOM was stronger than that of Pb2+.Two-dimensional asynchronous spectroscopy revealed the different complexation sites and sequences of HM and DOM,which provided a basis for studying the migration,transformation and biological toxicity of pollutants in natural water.