Research On Deep Purification Of Surface Source Farmland Wastewater By Improved Rapid Infiltration Methody

With the implementation of the rural revitalization strategy in China,the construction of an ecologically livable modern village is one of the important tasks.The current ecological and environmental problems in rural areas are mainly non-point source pollution,and the main source of pollution is agricultural non-point source pollution.Agricultural non-point source pollution causes environmental and ecological risks,water pollution,and soil fertility decline.Therefore,it is a problem that needs to be solved to control the agricultural non-point source pollution and reduce the non-point source pollution in China.Farmland wastewater is an important part of non-point source pollution.Water flows through the surface runoff of farmland,and water containing various organic pollutants produced by underground water seepage of farmland.These pollutants are directly remitted into rural surface runoff without treatment,causing Pollution of rural water environment.The pollutants contained in the wastewater are mainly CODcr,TN,TP,pesticides and then.In this paper,the artificial rapid infiltration system was used to treat surface source farmland wastewater,and the laboratory simulated farmland wastewater was used to conduct experimental research.The effect of artificial rapid infiltration system with different structures on the removal of main pollutants in farmland wastewater was investigated.The migration and transformation pathway of?P?in the improved artificial rapid infiltration system;from the perspective of enzymes and microbial communities,the mechanism of the improved artificial rapid infiltration system for farmland wastewater was studied,and the following conclusions were drawn:?1?Constructing two improved artificial rapid infiltration columns,A and B.When studying the effect of hydraulic load on COD removal,when the influent COD concentration is about 1500mg/L,when the hydraulic load is 10.5 cm/d,The COD removal rates of A and B columns were98.52%and 84.92%,respectively.When the hydraulic load was increased to 21 cm/d,the COD removal rates of A and B columns were 79.99%and 49.38%,respectively.The degree of decline.When studying the effect of influent organic load on COD removal,when the hydraulic load is10.5cm/d and the influent COD concentration is about 1500mg/L,the COD removal rate of A and B columns is 98.52%and 84.92%;When the influent COD concentration is about 1100mg/L,the removal rate of COD by A and B columns is 96.85%and 89.30%;when the influent COD is1500mg/L and 1100mg/L,the removal effect of A column is better than that of B column;When the influent COD concentration is about 600 mg/L,the average removal rate of effluent COD is94.94%and 95.52%,respectively,and the effect on the B column is slightly better than that of the A column.When studying the effect of hydraulic load on the removal of NH₄⁺-N,when the hydraulic load is 10.5cm/d,the removal rates of NH₄⁺-N from A and B columns are 91.73%and51.97%,respectively,when the hydraulic load is increased to 21 At cm/d,the removal rates of A and B columns were 48.46%and 47.53 mg/L,respectively.When the hydraulic load is 10.5cm/d and the COD concentration is about 660mg/L,the concentration of NH₄⁺-N is kept unchanged.The average concentration of NH₄⁺-N in the effluent of A and B columns is 0.33mg/L,1.05respectively.mg/L.When the effect of influent organic load on ammonia nitrogen removal was studied,when the COD value rose to 1100-1200 mg/L,the removal rates of NH₄⁺-N were 59.57%and 44.51%,respectively,indicating that the removal of NH₄⁺-N by excessive COD was observed.Has a certain inhibition.In the study on the removal effect of pesticide?Imidacloprid?and antibiotic?sulfamethazine?,the influent concentration of imidacloprid was 20-30 mg/L and the concentration of sulfamethazine was 1 mg/L under the condition of hydraulic load of 10.5 cm/d.Left and right,under this condition,the removal efficiency and stability of the B column on imidacloprid and sulfamethazine are better than that of the A column;when the hydraulic load is increased,the treatment effect of the B column is better than that of the A column.?2?Increasing the COD concentration and hydraulic load can improve the removal effect of TP on the two columns A and B.In the artificial rapid infiltration system,PH₃ mainly produces the drying period after the influent water,and reaches the maximum level within 5 hours after the influent;the phosphate-into the improved artificial rapid infiltration system,through the adsorption of the matrix,interception,under the action of microorganisms,PH₃ is dissolved in water or combined with the matrix,and transferred to the lower part of the percolation system with the penetration of water.As the gas continues to increase,it will gradually dissipate into the surrounding matrix,and when it reaches a certain concentration,it will escape to the outside through the vent pipe.When the external temperature is high,it escapes from the matrix of the surface of the diafiltration column to achieve the purpose of gasification and phosphorus removal.The surface of the matrix filler contains elements such as Fe,Mg,Al,Ca,etc.These elements are easily chemically reacted with phosphate in water to form a precipitate,which achieves the effect of solidifying phosphorus removal.?3?When the COD influent concentration is 550--650mg/L,the hydraulic load is increased from 10.5cm/d to 21cm/d,which promotes the nitrification,denitrification and removal of total phosphorus in the two columns.When the COD concentration is increased to about 1100 mg/L,the nitrification and total phosphorus removal are promoted.After three-dimensional fluorescence detection,it was found that there was no obvious characteristic peak in the influent.The effluent on the A column contained polycarboxylic acid type humic acid,and the effluent on the B column was mainly polycyclic aromatic hydrocarbon type humic acid.The results of fluorescence show that the DOM has a large increase after the influent is treated by the A-pillar B column.The two columns have microbial activity metabolism in the upper layer,which has certain metabolic effects on the pollutants.There is no obvious characteristic peak in the lower layer.It shows that after the lower layer treatment,the removal effect of pollutants is better.?4?According to the sequencing results of microbial communities on the matrix filler,a total of 34 phylum,95 order,and 607 genera were identified.The main dominant bacteria were Proteobacteria and Actinobacteria.Candidatus Saccharibacteria.The dominant flora at the target level are Actinomycetales,Sphingomonadales,Rhizobiales,Burkholderiales,and the like.The genus is mainly of the genus Saccharibacteria genera incertae sedis,unclassified genus,Arthrobacter,Sphingomonas,Pseudomonas and the like.The bacteria associated with COD degradation at the genus level are mainly Nakamurella and Agromyces.The genus associated with phosphine production is Escherichia coli/Shigella,and the dominant genus associated with the degradation of pesticides and antibiotics is Pseudomonas,Thauera,Nitrosomonas,Nitrospira and Nitrosospira.