Study On The Effect Of Humic Acid On Nitrogen And Phosphor Conversion Process In Black-odor Water

In recent years,various localities have vigorously carried out corresponding black and odorous water treatment projects according to their own characteristics,and found that although COD and other pollutants have been drastically reduced,TN is difficult to meet the standard.The reason is that in the current treatment process,people mainly pay attention to the nitrification and conversion of ammonia nitrogen in the water body,but ignore the removal process of nitrogen.At present,scholars have found a large amount of humic acid substances in the sewage body,and they believe that it will cause the water body to take a bad sensory color due to dissolution,which is a black factor.But there are also studies that have found that a moderate amount of humic acid in the water environment can give play to the "green" effect.Humic acid fertilizers have been a research hotspot in agricultural fertilization in recent years.Its dosing and use will have the risk of infiltration into natural water bodies.After entering the water body,humic acid will cause pollution to the water body,but due to its environmental chemical behaviors such as adsorption,chelation,hydrophobic distribution,and photochemical action,it is the influence in the water body is compound and varies with the influence of environmental factors.In view of the current research on nitrogen migration and transformation,most of the natural lakes and estuaries are the main research areas.There are few studies on the migration and transformation of nitrogen in black and odorous water,and there is no relevant research on the change and influence of humic acid in black and odorous water.This study is based on adjusting the concentration of humic acid,C/N,and aeration to explore the influence of nitrogen migration and transformation in static water body under different control methods,in order to explore the law of nitrogen migration and transformation in black and odorous water under the influence of humic acid,to provide guidance and reference for actual river governance.The main results are as follows:1.It is found that humic acid has obvious colloidal adsorption properties: when it just enters the water body,it will form the bottom of the humic acid micelle deposit,and absorb a large amount of pollutants at the same time,so that the turbidity,and ammonia nitrogen in the water body will rapidly decrease in a short time.And there are two large release time nodes in the process of the release of pollutants from humic acid micelles:the 17 th day and the 30 th day.After the high concentration of humic acid enters the water body and decomposes,it will promote the ammonia nitrogen,TN and TP in the water body to accumulate in the sediment.2.The influence of humic acid on the migration and transformation of nitrogen in black and odorous water has the following three aspects: providing external organic nitrogen and organic carbon to promote the nitrification process;affecting the change of DO,thereby affecting nitrification and denitrification;depositing at the bottom humic acid micelles will affect the diffusion process of nitrogen at the mud-water interface.3.Aeration can effectively promote the decomposition of humic acid and other organic matter in the water body,accelerate the process of nitrification,and it is easier to promote the aerobic ammonia oxidation process,and promote the migration of TP in the water body to the sediment;increasing C/N can be more obvious Locally promote the denitrification process,accelerate the removal of TN in the overlying water,and indirectly affect the migration of TP in the water body by affecting the content of DO in the water body.4.Through the analysis of the three-dimensional fluorescence spectrogram,it is found that the polluted artificial lake is manifested as biological self-source pollution,and the pollution of humic acid is manifested as terrestrial pollution.Increasing C/N and aeration can promote the migration and diffusion of humic acid.5.Through the micro-ecological analysis of the bottom sludge of the system,it is found that adding humic acid,aeration,and increasing C/N will reduce the species abundance of bacteria in the bottom sludge.Increasing C/N will reduce biodiversity and increase species uniformity,and adding aeration will reduce both;adding humic acid will reduce species uniformity,and humic acid concentrations of 10mg/L and100mg/L will increase the uniformity of species.Increased biodiversity,at 200mg/L,biodiversity will be reduced.The relative abundance of Proteobacteria and Chlorocurveae in water sediments is the highest;increasing C/N can inhibit actinomycetes from becoming dominant species,and aeration will favor actinomycetes to become dominant species,100mg/L humic acid Compared with 10mg/L and200mg/L,it is less likely to cause actinomycetes to become a dominant strain;changing C/N has little effect on the nitrite oxidation process.10mg/L of humic acid is more likely to make nitrosating bacteria become the dominant species,and increasing aeration is not conducive to nitrosating bacteria becoming the dominant species.