Study on the water-saving and pollution-reducing effect of biofilm–biofloc technique in Anguilla marmorata aquaculture

• Published in: Desalination and water treatment 2019-05, Vol.149, p.69-75
• Main Authors: Jiang, Xinglong, Zhang, Buqing, Zheng, Weigang, Zeng, Xiangbo, Li, Zhongqin, Deng, Laifu
• Format: Article
• Language: English
• Subjects: Carbon source supplements; Total ammonia nitrogen; Vibrio; Water exchange rate; Water treatment
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2019.23989

Daily water exchange rate was over 50% in the traditional intensive culture for Anguilla marmorata, which resulted in a huge waste of fresh water resources and the pollution of surrounding water. To save water and reduce pollution, the comparison experiment on biofilm–biofloc technique applied in Anguilla marmorata intensive culture was implemented. Nine tanks were randomly divided into three groups. Biofilm water-cleaning grille was set up at 7.1% of water volume, and supplementary sucrose was added to water at 75% of feed per day in treatment group I; biofilm water-cleaning grille was set up at 7.1% of water volume, and supplementary starch was added to water at 75% of feed per day in treatment group II; the other group III without any treatment as the control group. The results showed that the daily water exchange rate of treatment group I and treatment group II were significantly lower than the control by 69.2% and 74.4%, respectively (p < 0.05). The concentrations of total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen, total phosphorus, solved reactive phosphorus (SRP) and Vibrio density in treatment group I were lower than the control by 43.5%, 38.3%, 32.4%, 22.4%, 35.8%, 32.9%, and 45%, respectively (p < 0.05). While, the concentrations of the same mentioned parameters except SRP in treatment group II were lower than the control by 27.2%, 51.7%, 37.8%, 33.3%, 20.4%, and 50%, respectively (p < 0.05). The growth rate of treatment group I and treatment group II were significantly higher than the control by 37.8% and 14.9%, respectively (p < 0.05). Therefore, biofilm–biofloc technique had remarkable water-saving and pollution-reducing effect and should be extensively used in aquaculture.