超高密度全封闭循环水养殖系统设计及运行效果分析

为进一步研究循环水养殖系统在高密度养殖生产过程中的水质变化情况、鱼类生长情况及应用推广价值,该文构建了一套超高密度全封闭循环水养殖系统,设计3条水处理环路,集成了鱼池双排水、竖流沉淀、转鼓式微滤机、移动床生物过滤、多腔喷淋式纯氧混合装置、二氧化碳脱气等高效水处理技术和装备。提出一种基于投饲量的循环水养殖系统设计计算方法,重点考虑氨氮、溶解氧和总悬浮颗粒物3个水质指标。使用该系统养殖吉富罗非鱼6个月,试验研究结果显示:鱼类生长情况良好,最高养殖密度104.2kg/m3。饵料系数1.4,成活率92.2%。水质检测结果显示:氨氮浓度维持在平均(1.09±0.55)mg/L;溶解氧维持在4～9mg/L范围内;pH值6.45～7.41。经济性分析研究结果表明,系统养殖运行成本约为25元/kg,略高于市场价格。但是,从环境成本考虑,系统的节水效果显著,日耗水仅为0.3～0.5m3。通过适当的精简并挑选合适的养殖品种,完全可以实现规模化的生产。

Engineering design and performance evaluation of super high density recirculating aquaculture system

In order to research the change of water quality, growth of fish and economic benefits of the recirculating aquaculture system (RAS) under high density rearing conditions, a super high density RAS was developed. The system consists of three parallel water treatment branch equipped with some new technology, such as culture tank dual drain technology, radial flow settler, micro-screen drum filter, boiling type moving bed biofilm reactor, multiple chamber spraying oxygenator, CO2 degassing tower and etc. The paper also put forward a RAS design method which is based on three main water quality parameters, total ammonia nitrogen(TAN), dissolved oxygen concentration (DO) and total suspended solids(TSS). Using tilapia as the rearing object, 6 months experiment showed that the growth of tilapia was good, the highest culture density reached up to 104.2 kg/m3, the feed coefficient was 1.4 and the survival rate was 92.2%. During this period, TAN could be controlled at average (1.09±0.55) mg/L, DO 4-9 mg/L, pH 6.45-7.41. Economic evaluation results showed that the running cost of the system was about 25Yuan/kg fish, which was a little higher than the market price of tilapia. But considering the environment cost, the water saving effect of the system is significant, which is only about 0.3-0.5 m3 water per day, based on the measurement of the researchers. So, by properly simplifying the system and choosing some more suitable fish variety, recirculating aquaculture system will be valuable in the future.