Study On Purification And Resource Utilization Of Piggery Biogas Slurry Based On Chlorococcum Sp. And Daphnia Magna Straus

The efficient purification and resource utilization of piggery biogas slurry is the key technology for the sustainable development of pig intensive aquaculture.Biogas slurry is rich in nitrogen,phosphorus,organic matter and other nutrients,and nitrogen and phosphorus are important elements for the growth of microalgae.Using microalgae to purify the piggery biogas slurry,on the one hand,the pollutants in the sewage can be absorbed or sorbed by the microalgae to purify the sewage;on the other hand,the generated microalgae can be used for biomass energy,feed protein sources,etc.Using microalgae to purify the piggery biogas slurry has enabled the coupling of biogas slurry purification and resource recycling technologies to alleviate the multiple pressures currently faced by society such as environmental pollution,scarcity of fresh water resources,and energy shortages.The content of this paper includes three parts:1.Assessing the acclimation effect of Chlorococcum sp.,through gradually increasing high ammonia nitrogen concentration acclimation,and discussing the transcriptome differences of Chlorococcum sp.under different ammonia nitrogen;2.Study on filtration efficiency of Hyriopsis cumingii lea;3.the process design and effect of biogas slurry purification and resource utilization based on Chlorococcum sp.By gradually increasing the concentration of ammonia nitrogen(200,250,300mg/L)to acclimate green algae,the growth experiment was set up with 5 different ammonia nitrogen addition gradients,undomesticated(50,100,150,200,250 mg/L),domesticated(100,150,200,250,300 mg/L)were cultured for 7 days,and the changes of algae cell concentration,ammonia nitrogen,chlorophyll a,chlorophyll b,and carotenoids were detected.The results shows:uncultivated Chlorococcum sp.had the greatest relative growth rate at 50 mg/L ammonia nitrogen concentration,K was 0.41,and domesticated Chlorococcum sp.had the greatest relative growth rate of 0.36 at 150mg/L.Through domestication,the ability of purification efficiency and endurance on high ammonia nitrogen content can improved of Chlorococcum sp.,and showing good growth performance.When the concentration of ammonia nitrogen was 50 mg/L,the eradication rate of Chlorococcum sp.was 95.34%.After acclimation,the elimination rate was the highest,to 96.66%of Chlorococcum sp.,which is higher than the elimination rate of 100 mg/L in the non-acclimated group.Through acclimation,the concentration of Chlorococcum sp.can be improved,and ammonia nitrogen can be removed better.The transcriptomic sequencing was performed with high ammonia nitrogen(HAN-group,300 mg/L)and low ammonia nitrogen(LAN-group,100 mg/L)levels.The resulting transcripts were compared with Nr,GO and KEGG databases for annotating gene function,and analyzing the transcriptome status of Chlorococcum sp.under different ammonia nitrogen levels.The results show that there are 429 Unigenes in the nitrogen metabolism pathway between HAN-group and LAN-group.Among them,differentially expressed genes are enzyme-related coding genes involved in metabolic pathways,and the genes corresponding to the up-regulated genes include ferredoxin.Nitrite reductase and glutamate dehydrogenase(NADP+),while the down-regulated gene corresponds to the encoded enzyme glutamate synthase(ferredoxin related);1273Unigene were annotated in plant hormone signal transduction pathways.There are a total of 13 genes that have different expressions.Among them,the up-regulated gene corresponds to the encoded protein involved in the serine/threonine protein kinase SRK2;thedown-regulatedgenesinthepathwaymainlyincludethe pathogenesis-related protein 1,and the brassinosteroid non-sensitive 1 is related to A total of 651 Unigenes were identified in the body kinase 1,serine/threonine protein kinase CTR,and glutathione metabolic pathways,and there were 5 genes with differential expression.Totally.The ornithine decarboxylase mRNA expression level of the HAN-group was down-regulated.L-ascorbate peroxidase mRNA levels were significantly up-regulated.After culturing for two days,Hyriopsis cumingii lea were randomly divided into five groups,each group contains 14,average weight is 176±2g.,culturing in the designed device for measuring the filtration rate.Each group was added with different concentrations of microalgae(1,2,3,4,5×10~6cells/mL),at the temperature 20±1oC,light and dark ratio 0L:24D,the determination of the concentration of microalgae in different groups The changes were detected in the change of filtration rate and clearing rate of Hyriopsis cumingii lea.The results showed that with the increase of dietary concentration,the filtration rate of Hyriopsis cumingii lea increase first and drop.When the diet concentration was 2.0×10~6 cells/mL,the filtration rate of Hyriopsis cumingii lea reached top.with the increasing of microalgae concentration,the clearing rate of Hyriopsis cumingii lea continue to decline.Designing a process for the sustainable purification and resource utilization of piggery biogas slurry based on Chlorococcum sp.:anaerobic fermentation?flocculation sedimentation of piggery biogas slurry to reduce the content of suspended particles?adding ozone to reduce the turbidity and pathogen of biogas slurry Microbiological content?aeration reduces ammonia nitrogen,ozone content and conditioning?Chlorococcum sp.culturing and absorbing nutrients in biogas slurry?microalgae collection?uses Daphnia magnastraus to reduce the microalgae content in water?Daphnia magnastraus and microalgae are used in feed ingredients.Different supplement of green algae(0%,2.5%,5%)were fed to layer chickens and continuously fed for 27 days.Sampling every 3 days to detect the average daily egg production and egg weight,as well as the changes in egg yolk moisture,crude protein,color score,carotenoid content,crude fat,and fatty acid composition as breeding days increased.The addition of microalgae to layer chicken diets had no significant effect on the moisture content,crude protein content,total fat content,and average egg weight of egg yolk.With the increase of feeding time,there was no significant difference in the carotenoid content of the yolk without added algal flour(P>0.05).with the addition of algae powder added,the addition of algae powder group carotenoid and egg yolk color score showed an increasing trend,and from the sixth day was significantly higher than the no added algal flour group.The average daily egg production rate of laying hens in the 5%microalgae supplementation group increased significantly.The content of n-3PUFA,DHA,and ALA in the yolk powder group showed a similar deposition rule,showing a gradual increase in the21 days.On the 21th,it became saturated and then slowly declined.Compared with the 0%addition group,the n-3 PUFA,DHA,and ALA contents in the 2.5%addition group and the 5%addition group were higher than the 0%addition group during the test period.160 male shrimps with the size of 1.2±0.1 g were randomly and equally distributed among four transparent circular membrane pools with a water capacity of 1000 kg.The fresh water used was filtered through a 200 mesh sieve.The experiments were divided into two groups.,and each group was two parallel.Shrimp were fed with commercial feed and Daphnia magnastraus which were fed microalgae of sewage.Each group takes muscles and hepatopancreas of 15 shrimps on 0,15 and 30 days respectively.Measuring fatty acid composition and heavy metal content.When fed 15 days and 30 days,there was no significant difference in MUFA,PUFA,and HUFA contents in hepatopancreas of Macrobranchium nipponense a(P>0.05).At 15 days,the saturated fatty acid,ARA content in the feed group was significantly higher than that in the Daphnia magnastraus group(P<0.05),and the?-linolenic acid content in the Daphnia magnastraus group was significantly higher than that in the feed group(P<0.05).At 30 days,the content of linoleic acid in the large quail group was significantly higher than that in the feed group(P<0.05),and the C16:1 and EPA levels were significantly lower than those in the feed group(P<0.05).At the end of 30 days of culture,the Cu and Zn levels in the muscle and hepatopancreas feed groups were not as high as those in the large quail group.The contents of Cu and Zn in the large quail group were the highest at the day of the 30th day in the liver and pancreas of Macrobrachium nipponense,which was 97.15?g/g and112.62?g/g,respectively,while the Cu content in muscle reached a maximum of122.585?g/g at 15 days,and the content of Cu and Zn at the 30th day was 94.815?g/g and 61.675?g/g,respectively.Macrobrachium nipponense has enriched Cu,Zn heavy metals.