The Underwater Ecological Engineering System Designed Based On The Submerged Macrophytes And Its Ingestion By Fishes

At present,the construction of underwater ecosystem can be used as an important indicator of the preliminary ecological purification of water.The construction of Underwater Ecological Engineering Systems(Uw EESs)is an important symbol of water ecological purification technologies.Based on its successful cases and history,the Uw EESs based on fish feeding submerged macrophytes was constructed.Main conclusions are as follows:1)According to the influence of environmental parameters(i.e.inflow and water depth)on the growth of submerged macrophytes,a system with controllable conditions constructed.Results revealed the system exhibited good removal rates of nutrient pollutants.Average removal rate of NH₃-N could reach 90%.The most obvious conclusion was the water depth and flows directly affect growth of submerged macrophytes.Vallisneria Natans(VN),which exhibited weak tolerance to light,stressed at the depth of 1.2 m.However,Ceratophyllum Demersum(CD)and Hydrilla Verticillata(HV)could effectively utilize light sources.2)Consenquences revealed grass carp(Ctenopharyngodon Idellus)was preferred to eat HV.The relative growth rate of grass carp was up to 70%in the experiment only planted with HV.The feeding preference of grass carp to various submerged macrophytes ranked as follows:HV>CD>VN.3)Consenquences revealed the variation of phytoplankton in different months was significant while the species co-existing in the adjacent months exhibited great difference.Different species of phytoplankton affected by many environmental factors,i.e.,temperature,p H,and dissolved oxygen concentration.4)Biochar were prepared by recycling overgrown plants,which exhibited the maximum adsorption capacity when the materials were at 450°C.It caused by the active persistent free radicals,phenolic resin,and redox active groups.The adsorption process is more fitted with Langmuir isotherm and Pseudo-second-order adsorption kinetic model.Figure 32;Table 13;Reference 103...