Study On Purification Of Mariculture Tailwater By Microalgae-Probiotics Symbiosis System

With the rapid development of economy and society,intensive land use and high-output aquaculture models will become a new hot spot for industrial development,and the discharge of mariculture tailwater from high-density farming will cause local environmental impacts.At present,due to technical constraints and pressure on treatment costs,it is difficult to imple physical and chemical methods similar to urban sewage treatment for large-scale mariculture tail water treatment.Against the backdrop of stricter environmental protection regulations in China,environmentally friendly production technologies have long-term and extensive social needs.The research object of the paper is mariculture tailwater.The research direction is low-cost,low energy consumption,and high-efficiency aquaculture tail water treatment mode.The microalgae and probiotics are used to absorb the rich nutrients in the tailwater to make the water quality meet the standard.Recycling,to achieve a win-win situation of environmental protection standards and the utilization of breeding tailwater resources.The main results were summarized as follows:1.By experimental verification,Chaetoceros muelleri,Chlorella pyrenoidosa,Pavlova viridis,and Platymonas subcordiformis,the four microalgae as well as two probiotic bacteria of Rhodotorula benthica and Bacillus subtilis,have been used in the seawater culture.Denitrification and dephosphorization of water have certain effect in purifying tail water.The removal efficiency of Chlorella pyrenoidosa to ammonia nitrogen is the best,the removal rate is 62.79%;the removal efficiency of pavlovia viridis to nitrite is the best,the removal rate is 98.47%;the removal efficiency of Chaetomium mulleri to various forms of P is the best,the removal rate of soluble phosphate is 88.85%,and the removal rate of total phosphorus is 84.52%.2.According to the treatment results of the pure culture system of microalgae and probiotics on the mariculture tail water,the symbiotic system of microalgae-probiotics is composed of Chaetomium mucronatum,pavlovia viridis,Rhodotorula benthica and Bacillus subtilis to play the purification effect of complementary advantages of four kinds of organisms.The orthogonal design method was used to determine the optimal quantity ratio of microalgae and probiotics symbiosis system to purify the tail water of mariculture.When the inoculated biomass of Chaetoceros mulleri,pavlovia viridis,Rhodotorula benthica and Bacillus subtilis were 3.1×10⁶cells/ml,2.0×10⁷cells/ml,1.9×10⁹cells/ml,5×10⁹cells/ml,respectively,and the inoculated volume was 20ml,5ml,1ml and 1ml,the purification effect was the best.The removal rates of NH₄⁺-N,NO₂^--N,TN,PO₄^3--P and TP were 54.05%,96.43%、83.71%、81.99%、82.12%.