Screening Of Aquatic Plants For Purification Of Carbon,Nitrogen And Phosphorus In Freshwater Fish Ponds And Aquarium Aquarium Tail Water

Standard discharge after treatment of aquaculture tail water is an important guarantee to ensure the green development of aquaculture.Aiming at the problem of fewer species of aquatic plants in aquaculture tail water treatment,this article develops the use of aquatic plants to purify freshwater fish ponds and aquarium aquaculture tail water carbon and nitrogen Phosphorus test.Fresh water treatment is divided into indoor static water experiment and outdoor polyculture pond production test.Seawater treatment is indoor static water experiment.Through experimental comparison and analysis,the application prospects of aquatic plants in the treatment of aquaculture wastewater are discussed,and a scientific basis is provided for the establishment of a healthy,ecological and sustainable cultivation model.1.Study on the removal effect of Myriophyllum elatinoides Gaudich,Ipomoea aquatica Forsk and Eichhornia crassipes on carbon,nitrogen and phosphorus in aquaculture waterTest in 2nd October to 12th November 2017,carried out for a period of 42days,choose Myriophyllum elatinoides Gaudich,Ipomoea aquatica Forsk and Eichhornia crassipes as the test plant,freshwater aquaculture tailwater reference tilapia intensive pond water quality,"freshwater aquaculture water discharge requirements"and phosphorus values severe eutrophication of rivers,eutrophic water low level setting,medium,and high group,the TN and TP concentrations of 5,10,15 and 1,2,3mg·L^-1,measured periodically Plant fresh weight,nitrogen and phosphorus content and water quality indicators:COD_Mn,TOC,NH₄⁺-N,TN,SRP and TP,analyzed the growth status of the three plants,the accumulation of nitrogen and phosphorus,and their ability to remove carbon,nitrogen,and phosphorus.The results are as follows:（1）The growth and accumulation of nitrogen and phosphorus of Myriophyllum elatinoides Gaudich increases with the increase in the concentration of nitrogen and phosphorus in the water,hi high nitrogen phosphorus;Ipomoea aquatica Forsk continued growth28d,growth with increasing concentrations of nitrogen and phosphorus decreases,hi high nitrogen but impatience high nitrogen;Pistia stratiotes L.low,the growth nutrient level group 21d,only high-level group 14d,growth with As the concentration of nitrogen and phosphorus increases and shortens,the growth and accumulation capacity of nitrogen and phosphorus decrease accordingly.It likes phosphorus but is sensitive to high nitrogen.（2）The removal rates of Myriophyllum elatinoides Gaudich on the COD_Mn,TOC,NH₄⁺-N,TN,SRP and TP of the culture tail water reached 60.02-62.89%,34.59-53.35%,95.17-97.10%,69.53-87.40,respectively,69.99-90.00%and 68.87-84.42%,the removal effect of carbon,nitrogen and phosphorus increases with the increase of nitrogen and phosphorus concentration,strong ammonia resistance;the removal rate of Ipomoea aquatica Forsk on nutrients is 39.32-46.79%,18.74-27.49%,78.93-89.88%,58.80-66.15%,39.97-46.99%,and 30.89-47.69%.The removal effect of carbon,nitrogen and phosphorus decreases with the increase of nitrogen and phosphorus concentration in the water body,and the removal capacity is second to that of Myriophyllum elatinoides Gaudich.The plant growth is limited in the later stage,and the removal capacity is Slightly inhibited;the removal of carbon,nitrogen and phosphorus by Pistia stratiotes L.is similar to that of Ipomoea aquatica Forsk,and the removal rates are 30.24-53.00%,4.11-24.97%,39.37-72.67%,55.54-59.16%,39.13-52.17%,and 34.88-58.97%.It is concluded that the removal ability of the three plants on the carbon,nitrogen and phosphorus of the culture tail water is in the order of Myriophyllum elatinoides Gaudich>Ipomoea aquatica Forsk>Pistia stratiotes L.Myriophyllum elatinoides Gaudich can be used for the long-term purification of various types of farming tail water with excessive nitrogen and phosphorus,especially suitable for high The eutrophication of nitrogen and phosphorus culture tail water,Ipomoea aquatica Forsk is suitable for the improvement and purification of high nitrogen pond culture tail water,and the short-term treatment of high phosphorus culture tail water can be considered for Pistia stratiotes L.2.Application of three aquatic plants in tilapia pond cultureTest in May-December 2017 aquatic breeding base Guangxi University Teaching 8 piece of 0.1-0.15ha ponds to carry out,in the main tilapia,respectively,silver carp and bighead carp polyculture pond in setting accounting pond Three floating bed treatment groups with 10%of the area of Myriophyllum elatinoides Gaudich,Eichhornia crassipes,and Pistia stratiotes L.,and a control group without plants,regularly monitor the water quality indicators of the pond water body:p H,DO,chlorophyll a,chlorophyll b,NH₄⁺-N,NO₂^--N,TN,SRP,TP,COD_Mn and BOD₅,the fish weight,plant biomass and plant nitrogen and phosphorus content were measured at the beginning and end of the experiment,and the application of the three plants in tilapia aquaculture production was compared and analyzed effect,the results are as follows:（1）during the test,the group of plant floating bed water p H value,the DO stable in the range suitable for growing fish,significant reduction in chlorophyll concentration;the TN,TP ranges are 0.58-2.21 and 0.109-0.279 L·mg^-1,Myriophyllum elatinoides Gaudich,Eichhornia crassipes and Pistia stratiotes L.of the TN,TP removal rate were68.80%,64.61%,63.97%and 53.76%,47.95%,36.51%,Myriophyllum elatinoides Gaudich and Eichhornia crassipes purification effect of nitrogen and phosphorus is better than that of Pistia stratiotes L..The plant floating bed group TN,TP and BOD₅ all meet the first-level emission standard of freshwater pond culture tail water,COD_Mn meets the second-level emission standard,and the purification effect of COD_Mn is the Pistia stratiotes L.>Myriophyllum elatinoides Gaudich>Eichhornia crassipes.（2）Eichhornia crassipes and Pistia stratiotes L.grow rapidly but the plants turn yellow and rot in the later period,and the growth state of Myriophyllum elatinoides Gaudich is the best in the later period.After the experiment,the net biomass increase of Myriophyllum elatinoides Gaudich,Eichhornia crassipes and Pistia stratiotes L.is 1071.4,2232.8 3545.1kg respectively,the nitrogen and phosphorus removal amounts were 0.31,0.25,0.17 and 0.17,0.04,0.07 kg·m^-2,respectively.The removal of nitrogen and phosphorus per square meter of Myriophyllum elatinoides Gaudich was the highest,and the plant growth status was the best;The Pistia stratiotes L.group was in the middle,The Eichhornia crassipes group is worse.（3）Treatment groups of three plant floating bed pond fish per unit net production was 14497.5,12857.5and 11274.7 kg·ha^-1,Myriophyllum elatinoides Gaudich group pond fish highest yield per unit area,Pistia stratiotes L.secoud group,Eichhornia crassipes poor groups.In summary,it can be seen that Myriophyllum elatinoides Gaudich,Eichhornia crassipes,and Pistia stratiotes L.are all suitable for the construction of floating bed plants to construct pond water purification systems.After treatment,the water quality indicators of the aquaculture tail water meet the discharge standards,and the fishery output has been improved to a certain extent.During the breeding cycle,Myriophyllum elatinoides Gaudich has the best adaptability to the changes in pond water quality,and the fishing yield and the amount of nitrogen and phosphorus removal are the highest.In the production,Myriophyllum elatinoides Gaudich is preferentially selected for freshwater pond culture tail water treatment.3.Screening of plants for purification of nitrogen and phosphorus in aquaculture tail water of the aquariumThis research trials in 12th-19th December 2016 to carry out a period of8days,according to Shanghai Ocean Aquarium offers indoor cultivation of tail water of nitrogen and phosphorus concentration and salinity formulated farming simulation Oceanarium tail water(NH₄⁺-N,NO₂^--N,NO₃^--N and SRP are 0.02,0.012,14.6 and 10mg·L^-1 respectively,and the salinity is 30).Four types of large seaweeds commonly found in the coast of Guangxi Beihai are adopted.-Gracilaria tenuistipitata,Gracilaria asiatica,Acantophora spicifera and Enteromorpha is cultured using 500m L Erlenmeyer flask was added 400m L test water,tail water purification experiment where culture,fresh algae measured regularly during the test weight,The content of nitrogen and phosphorus,the activity of antioxidant enzymes POD and SOD,and the content of NO₂^--N,NO₃^--N,NH₄⁺-N and SRP in the water body,by comparing and analyzing the growth and nitrogen and phosphorus removal of four kinds of seaweeds The results are as follows:（1）During the experiment,Gracilaria tenuistipitata can grow normally,and the Gracilaria asiatica begins to decay 2 days after the experiment started,and Acantophora spicifera and Enteromorpha decomposed from the beginning of the experiment.Grow.（2）Gracilaria tenuistipitata had the ability to remove nitrogen in the culture tail water during the 8 days of the experiment in the order of NH₄⁺-N>NO₃^--N>NO₂^--N,99%,94%and 76.1%respectively,the initial absorption of DIN in the water body was faster,and the removal rate of NO₃^--N and NH₄⁺-N in 2 days could reach 77.6%and 70%respectively;the removal rate of SRP was poor,and the test ended.The removal rate of SRP from aquaculture tail water is only 59.06%.Gracilaria asiatica can only remove N and P nutrients within 2 days before the experiment.The removal rate is as follows:NH₄⁺-N>NO₃^--N>NO₂^--N>SRP,70.00%,50.03%,25.51%and 19.55%respectively;decomposed afterwards.By the end of the experiment 8 days,the weight loss rate was 2.28%.TN and TP released 22.74%and 10.47%respectively.（3）Acantophora spicifera and Enteromorpha decomposed from the beginning of the experiment.At the end of the experiment,the weight loss rates of Acantophora spicifera and Enteromorpha were 39.75%and 36.58%,respectively,which were in the early decomposing process.algae,TN release rate greater than TP,and N,P release sync;time to the end of the experiment,Acantophora spicifera and Enteromorpha released Decomposition of TN and TP of respectively 65.92%,62.69%and 35.27%,28.53%.（4）POD and SOD enzyme activities:during the test period,there was an upward trend in the body of Gracilaria tenuistipitata and Gracilaria asiatica,and the two enzyme activities of Gracilaria tenuistipitata were greater than those of Gracilaria asiatica.Gracilaria tenuistipitata had an effect on high salt and high nitrogen.The adaptability is stronger than that of Gracilaria asiatica;the two enzyme activities of Acantophora spicifera and Enteromorpha tend to decline,and the stress resistance is poor,and it is not suitable for growth in a high-salt and high-nitrogen environment.To sum up:the end of a high salt water aquaculture Nitrogen,Gracilaria tenuistipitata Growth and N,P removal capacity are superior Gracilaria asiatica,Acantophora spicifera and Enteromorpha can not grow were Decomposition occurred,and thorn-like The decomposing degree and the release of N and P of Acantophora spicifera are higher than those of Enteromorpha...