Study On Reuse Technology Of Filter Material For Tail Water Treatment Of Freshwater Pond Culture

Today,with the rapid development of aquaculture,scientific and technological development and economic benefits have made considerable achievements.High-density pond breeding is a relatively common breeding mode in China.The traditional pond breeding method discharges a large amount of residual bait and manure into the water body,resulting in increasingly serious tail water pollution.The emerging pond aquaculture method avoids the drawbacks of conventional aquaculture methods,and the pond factory circular aquaculture technology characterized by high-density intensification has been widely promoted.However,at the same time,in the process of practical application,it is also difficult to accurately adjust the water quality of the pond and the high requirements for the safe operation of power supply and aeration equipment.Aquaculture tail water treatment and reuse have become a key link to realize the green and sustainable development of aquaculture.This paper mainly analyzes the innovative treatment methods of the pond aquaculture tailwater treatment system,the treatment effect of filter materials and the reuse of filter materials.This study proposes to introduce an "all-weather" meteorological-water quality monitoring station to build a new application model for pond aquaculture tailwater treatment,to detect and evaluate the purification effect of freshwater pond aquaculture tailwater,and analyze the microbial community structure and function of different treatment methods of polluted filter materials,with a view to today.The healthy and sustainable development of the post-pond aquaculture industry provides reference.The main research contents and results are as follows:1.Innovative construction of "five pools and two dams" freshwater pond aquaculture tailwater treatment systemOn the basis of the construction of the "five pools and two dams" system,in order to monitor the water quality changes of each unit of the breeding tailwater treatment system in real time in real time according to seasonal meteorological conditions,and to observe,analyze and compare the tail water treatment effect of each unit,this study has installed a weather station and a real-time online monitoring system to monitor atmospheric pressure,atmospheric temperature,rainfall,humidity and wind direction in real time;and to monitor chemical oxygen demand(CODMn),ammonia nitrogen(NH4+-N),total nitrogen(TN),total phosphorus(TP)and other indicators in real time.In addition,according to relevant data,the service life of aquaculture tailwater treatment filter material is generally 3 to 5 years.The "five pools and two dams" system built in this study has been in operation for about three years.In order to evaluate the operation of the system,especially the cleaning and reuse effect of filter materials,a filter material cleaning and reuse system has been innovatively built to monitor the chemical oxygen demand(CODMn),ammonia nitrogen(NH4+-N),total nitrogen(TN)and total phosphorus(TP)in freshwater pond tailwater before and after filter material cleaning in real time.2.Evaluation of the effect of aquaculture tailwater treatment for meteorological monitoring and filter cleaning and reuseThe cleaning,regeneration and reuse test results of filter materials show that during the operation of the system,the average removal rates of CODMn,NH4+-N,TN and TP in the cultured tailwater are 90.63%,33.66%,21.24% and 76.11% respectively.The effluent quality meets the first-level standard of the Freshwater Pond Aquaculture Water Discharge Standard(GB38-2002),and the removal effect is remarkable.This provides technical support for the reuse of aquaculture tailwater treatment filter materials,the extension of the service life of the filter materials,and the reduction of the cost of aquaculture tailwater treatment.3.Community structure and functional analysis of mud microorganisms in different units of the "five pools and two dams" systemIn this study,the 16 Sr DNA high-throughput sequencing method was used to analyze the structure and function of the microbial community of "precipitation tank I","filtration dam I","precipitation dam I","precipitation tank II","aquatic organism purification pool" and the bottom mud of the untreated pond before and after physical cleaning of filter materials in the "five pools and two dams" pond aquaculture tailwater treatment system respectively.After filter treatment,most of the bacteria in the "aquatic biological purification tank" are Gram-positive bacteria.They are aerobic,have motor flagella or hair,and can form biofilms.The proportion of harmful bacteria in the flora structure is reduced,which helps to improve water quality.Alpha diversity analysis found that after the filter material was cleaned,the microbiodiversity of "precipitation tank I" increased,while the "aquatic biopurification tank" decreased significantly.It shows that the filter material treatment is conducive to the unification of the flora abundance of each treatment tank in the freshwater pond aquaculture tailwater treatment system,and to the restoration of the filtration function of the filter pond.PCA and PCOA diversity analysis found that most of the microbial clusters in each unit pool can cluster separately,and there are significant differences between groups.It shows that the filter material effectively restores the diversity of habitat species in the freshwater pond aquaculture tailwater treatment system after cleaning,and effectively distinguishes the microbial similarity of each treatment tank.The species abundance cluster analysis found that before the filter material treatment,the composition of the "precipitation tank I" bottom mud flora is relatively different from that of the other four pools,and there is also a gap between the flora composition of different pool bottom mud before and after tailwater treatment.After filter material treatment,there is a big gap between the composition between the "aquatic organism purification pool" and the remaining four pools.This analysis shows that the cleaning of filter materials is conducive to the growth of bacteria of the same species in inlet tanks,filter tanks,sedimentation tanks,and untreated ponds,and these advantageous bacteria may help improve water quality and promote the growth of aquatic plants.