The New Harmless Treatment And Resource Utilization Of Piggery Biogas Slurry By Algae-Rotifer System

This study aimed at the large number of pollutants in livestock and poultry farming in China,as well as the indiscriminate treatment of pollutants and weak resource utilization.It selected pig manure as raw material and used upstream anaerobic sludge blanket（UASB）.After the fermentation process,biogas,biogas residue and biogas slurry are obtained.Biogas is used for power generation and gas.Biogas residue is used for fertilizer return.Biogas and biogas residue are efficiently utilized,but biogas slurry is not used effectively and discharged directly into the environment.Can cause a great deal of pollution.The concentration of COD,BOD₅,ammonia nitrogen,and phosphate in the biogas slurry produced by the UASB process was 138 mg/L,38 mg/L,and 385 mg/L,respectively.At64.3 mg/L,the COD and BOD₅ values were much lower than those of the original manure,but the degradation effects of ammonia nitrogen and phosphate were not obvious.For the deep purification and resource utilization of biogas slurry,this study has great potential for sewage treatment based on the chlorella mentioned in the literature.The protein was determined by comparing the growth rate and purification effect of different Chlorella in biogas slurry.The optimum dilution of Chlorella as an algal species and biogas slurry in this study was 1:10 and the culture time was 10 days.Based on the interaction between bacteria and algae and the self-utilization value of each strain,a composite strain composed of Rhodopseudomonas palustris,Lactobacillus acidophilus,and Candida utilis was established,and the algae-based bacteria were eventually established.Supplementary bacteria and algae system.Combined with the literature,it was established that the final concentrations of Pseudomonas palustris,Lactobacillus acidophilus and Candida utilis in the complex were 1×10⁴ CFU/mL,1×10³ CFU/mL,and 1×10⁴ CFU/mL,respectively.The inoculation amount of Chlorella pyrenoidosa was 1×10⁶ cells/mL.Under the conditions of28℃,3000 lux,and light and darkness for 12 h:12 h,the ability to purify the biogas dilution of 1:10 in the optimum biogas slurry and the biomass produced were compared by comparing the complex bacteria,Chromophyll Chlorella,and algae.The results showed that the degradation rates of COD,BOD₅,ammonia nitrogen,and phosphate were respectively 88.6%,86.9%,91.3%,and 82.4%,and the biomass was 5.19 g/L,which was higher than that of the composite group（10 days）.The removal rates of COD,BOD₅,ammonia nitrogen,and phosphate were 60.1%,63.1%,57.4%,and 49.9%,respectively,and the biomass of the cells after vacuum drying reached 3.26 g/L)and Chlorella pyrenoidosa（10 d）.The removal rates of COD,BOD₅,ammonia nitrogen,and phosphate were 82.7%,81.6%,82.0%,and 71.9%,respectively,and the biomass of the algal biomass reached 2.41g/L after vacuum drying.By constructing a highly efficient algae and algae system and using a biogas slurry rich in nutrients as a culture medium for bacteria and algae,the main contaminants in the biogas slurry are not only effectively utilized,but also produce a nutrient-rich fungal algae body.In order to solve the problem of difficulty in collection of large-scale culture of algae,the characteristics of rotifer-intaking algae were used to inoculate a certain amount of Brachionus calyciflorus in logarithmic phase to construct the algae-rotifer system.the density of rotifers can be increased from 10/ml to 220/mL in 4 days,and the rotifers’phototaxis can be used for the net fishing collection.The bacteria and algae can be transformed into high-nutrient aquatic food rotifers efficiently.At the same time,the photobioreactor was designed to simulate the production.The growth rate of bacteria and algae was significantly faster than that of static culture in the light incubator.The novel algae-rotifer system constructed in this study has great application prospects,and provides theoretical guidance and technical means for the harmless treatment and resource utilization of the biogas slurry in the farm.