Study On The Construction Of Ecological Revetment Protection And The Efficiency Of Nitrogen And Phosphorus Removal Based On The Improvement Of River Habitat

To reduce pollution load and improve the self-purification capacity of the river,with Fu River and Xiaoyi River as our main research objects,ecological revetment experiments were carried out on both rivers.In this paper,the effect of different revetment types on the improvement of soil denitrification and phosphorus removal and the purification of water quality was systematically studied,the reasons for the change of soil nitrification and denitrification capacity in the revetment zone were carefully analyzed,and the microbial community structure of the revetment zone was discussed.A river restoration technology based on the construction of ecological revetment was proposed and the engineering demonstration was carried out.The main results achieved are as follows:1.Constructed ecological revetment and habitat improvement system based on gabion and pine pile ecological revetment separately.The stability and erosion resistance of the ecological revetment were measured:the anti-erosion coefficient increased from 2.067 L/g to almost saturated for gabion ecological revetment and 1.848 L/g to 3.145 L/g for pine pile ecological revetment.With the stability and erosion resistance of the riverbank improved with both systems,and gabion ecological revetment gives better result than pine woodpile revetment.2.Overall,the nitrogen and phosphorus removal efficiency are both improved for the gabion and pine pile ecological revetment system.The nitrogen and phosphorus conversion capacity was measured for both systems.The nitrification rate is increased from 0.265mg/kg·h and 0.15 mg/kg·h to 0.375 mg/kg·h and 0.34 mg/kg·h,and the denitrification rate is changed from 178.90μmol N·m^-2h^-1and 180.28μmol N·m^-2h^-1to 154.98μmol N·m^-2h^-1and481.08μmol N·m^-2h^-1for gabion and pine pile revetment respectively.While the soil denitrification efficiency in the revetment zone is improved in both systems,the pine pile revetment provides better results than the gabion one.In addition,the abundance of denitrification functional flora is also increased,for example,Nitrospirota increased by 104%and 129%in the gabion revetment and pine pile systems respectively.The phosphorus adsorption capacity and total adsorption capacity for both systems are slightly increased as well.3.The ecological restoration demonstration projects of Fuhe and Xiaoyi Rivers inXiong’an New District have increased the self-purification capacity of river water.It is shown that the ammonia nitrogen in Habitat Improvement Area is reduced by 30.2%and 15.8%,and the total phosphorus is reduced by 18%and 44.1%in Fu River and Xiaoyi River respectively.