Bacteria And Algae Immobilized Pellets For Aquaculture Wastewater Denitrification And Phosphorus Removal Effect Research

The co-immobilized bacteria-algae system’s removal ability of nitrogen and phosphorus inaquaculture ponds was mainly studied in this experiment. According to the studies of theaquaculture ponds’ background level, we isolated and screened nitrobacteria, denitrobacteriaand Bacillus subtilis, purchasing of Scenedesmus quadricanda、Selenastrum capricornutum andChlorella pyrenoidosa as experimental microorganisms. Then determined which bacteria andalgae had the best ability in removal of nitrogen and phosphorus, finally, established theoptimum co-immobilization bacteria and algae model in nitrogen and phosphorus removal. Atlast, the system’s purifying effect to the actual aquaculture ponds water was clarified.This experiment mainly focused on the sreening and identification of the bacteria and algaeused in immobilized, the effects on nitrogen and phosphorus’s removal with different levels andfactors on the bacteria or algae’s separated immobilized,the bacteria and algae’s volumes ofco-immobilization system, and system’s purifying affect to the actual aquaculture ponds water.The main results were summarized as follows:⑴According to the determination of the indicators such as the water quality and thenumber of algae species on the turtle aquaculture ponds, we could read that: the value of TN,TP, ammonia nitrogen and COD was significantly higher than the standard level in intensiveaquaculture ponds, which caused the decreased in algae species and the more changes in thenumbers. So we should use the microbial with better removal ability of nitrogen andphosphorus to adjust the water quality.⑵Nitrobacteria, denitrobacteria and Bacillus subtilis were isolated and screened from thenature, which were identified as Acinetobacter sp.and Bacillus subtilis Scenedesmusquadricanda、 Selenastrum capricornutum and Chlorella pyrenoidosa were purchased asexperimental microorganisms and proved good growth and reproduction abilities in thelaboratory conditions. By the experimental verification, denitrobacteria,Bacillus subtillis,Chlorella pyrenoidosa and Scenedesmus quadricanda had better ability in removal nitrogen andphoaphorus,what’s more, these four species had the advantage of a complementary role.⑶The optimum microorganism ratio was estabished according to the orthogonal testdesign. The volume ratio of Scenedesmus quadricanda: Chlorella pyrenoidosa: denitrobacteria:Bacillussubtillis is3:3:2:3; the best factor level is: the concentration of sodium alginate is4%,theproportion of bacteria and glue is6/30, the concentration of calcium chloride is3%,theconcentration of PVA is2%. Under this immobilization condition, the removal efficiencies ofammonia nitrogen, nitrite nitrogen and TP is100%,100%and83.8%respectively.⑷The co-immobilized bacteria and algae system’s nitrogen and phophorus’s removalresults with actual aquaculture ponds water indicated: The removal effect with ammonia nitrogen, TP and nitrite nitrogen of this system is obviously good,the degradation ratio withammonia nitrogen,nitrite nitrogen and low concentrations of TP were all up to100%,thedegradation ratio with high concentrations of TP was more than80%, Put the co-immobilizedsystem directly in the aquaculture ponds water had the better affect than sterilizationtreatment,the degradation ratio with ammonia nitrogen, nitrite nitrogen and TP were up to100%,100%and99.15%.The result indicated the co-immobilized system had a synergisticeffect with the original species, which enhanced the effect of removal the nitrogen andphophorus, this system had some practical application.