Studies On Construction And Its Purification Activity For Water Of Algae-bacteria Symbiotic Globules

With the release of the discharge standard for pollutants from aquaculture water,the comprehensive treatment and ecological restoration of aquaculture water will become one of the important elements in daily management of aquaculture.It will become an important industry and technical demand for aquaculture to develop in-situ and ex-situ purification technology of nutrients in aquaculture water.Algae-bacteria symbiosis system is a kind of combination,which is used to purify sewage by the synergy between algae and bacteria.In this study,Chlorella vulgaris and Aspergillus oryzae were taken as research objects to construct symbiotic globules of algae and bacteria,optimize their symbiotic conditions and analyze globules’purification ability of nitrogen and phosphorus in the pond water of fish aquaculture and Macrobrachium rosenbergii aquaculture respectively.In order to provide technical support for purification treatment of aquaculture pond water.The main results were summarized as follows:（1）Construction of algae-bacteria symbiotic globules and the removal efficiency of nitrogen and phosphorusIn this study,the Chlorella-Aspergillus symbiotic globules were prepared and optimized to analyze their removal efficiency of nitrogen and phosphorus in simulated aquaculture water.The results showed that it was the best of the molding effect of Aspergillus oryzae globules at p H=7 and rotating speed of 160 r/min.When 350 Aspergillus oryzae globules were mixed with algae cells at a concentration of 4.8×10⁶ cells/m L,the highest fixation rate of 99.88%was achieved,in addition,the algae-bacteria symbiotic globules（0.2±0.01 cm,n=60）could effectively remove ammonia nitrogen（NH₄⁺-N）,nitrite nitrogen（NO₂^--N）,nitrate nitrogen（NO₃^--N）,total nitrogen（TN）,phosphate(PO₄^3--P)and total phosphorus（TP）in water within 48h,the average removal efficiencies were 90.66%,93.43%,98.74%,60.19%,94.87%and 79.91%,respectively.The removal ability of algae-bacteria symbiotic globules for nitrogen and phosphorus remained stable over a 48 h period and was better than that of the single algae and single bacteria.（2）Removal of nitrogen and phosphorus by algae-bacteria symbiotic globules in the fish aquaculture pond waterThe removal effect of nitrogen and phosphorus in the fish aquaculture pond water by using the constructed Chlorella-Aspergillus symbiotic globules showed that:the removal ability of algae-bacteria symbiotic globules depending on different treatment methods.Among them,the average removal efficiencies of symbiont in sterilized aquaculture pond water were 92.96%,95.52%,81.52%,35.55%,91.57%and 79.45%for NH₄⁺-N、NO₂^--N、NO₃^--N、TN、PO₄^3--P and TP respectively;In non-sterilized aquaculture pond water,the average removal efficiencies were 98.22%,80.40%,89.46%,34.29%,92.90%and 84.48%for nutrients respectively.Within 48 hours,algae-bacteria symbiotic globules could quickly and effectively reduce nitrogen and phosphorus nutrients in aquaculture pond water,enabling it to reach the second level of Discharge Standard of Pollutants for Aquaculture Tail Water in Hunan Province,and the purification effect of algae-bacteria symbiotic globules on on-sterilized aquaculture pond water was generally better effect than that of sterilization treatment.（3）Removal of nitrogen and phosphorus by algae-bacteria symbiotic globules in the Macrobrachium rosenbergii aquaculture pond waterThe removal effect of nitrogen and phosphorus in the Macrobrachium rosenbergii aquaculture pond water was studied by using the algae-bacteria symbiotic globules.The results showed that the removal ability of algae-bacteria globules depending on the water treatment methods were different.Among them,the average removal rates of the symbiont on NH₄⁺-N、NO₂^--N、NO₃^--N、TN、PO₄^3--P and TP in sterilized aquaculture pond water were 89.99%,99.19%,98.48%,and 63.34%respectively.The average removal rates for NH₄⁺-N、NO₂^--N、NO₃^--N、TN、PO₄^3--P and TP in non-sterilized aquaculture pond water were99.10%,2.15%,96.52%,62.38%,96.77%and 92.00%respectively.The results showed that ammonia nitrogen was first absorbed and utilized by algae-bacteria symbiotic globules,and the water quality reached reached the second level of Discharge Standard of Pollutants for Aquaculture Tail Water in Hunan Province after 48 h of purification.Under the same conditions,the removal effect of nitrogen and phosphorus in non-sterilized aquaculture pond water was generally better than that sterilization treatment within 48 hours.