Design and test of mass balance-based recirculating aquaculture system for higher place shrimp pond

Abstract: Higher place shrimp pond is an important production mode in China's shrimp production mode, but there are problems such as low utilization rate of water resources and pollution of aquacultural waters. In this paper vannamei as an object, using material balance principle and water purification facilities construction technology, including total ammonia balance, nitrification reaction oxygen balance, dissolved oxygen balance and the relationship between surface load and sedimentation rate of inclined pipe precipitation facility. To construct a highly efficient, low-cost of high pool recirculating aquaculture system, fluidized bed biological filtration facility volume were calculated using total ammonia balance. Based on the principle of dissolved oxygen balance, the oxygen demand of the system was calculated based on the oxygen consumption of nitrification and the dissolved oxygen concentration. Several key parameters were precisely established, such as physical filtration equipment of water treatment system volume, the volume of biological filtration facility, the circulating volume, oxygen supply and so on. According to the calculation results as well as taking into account the structure of the facilities between the convergence, and considering management and other factors, structure parameters of the system were determined, and a high pool recirculating aquaculture system were established, which including higher place shrimp pond and corresponding water treatment facilities and equipment, belt filter, pipe chute sedimentation facilities, fluidized bed biological filtration facility, aerobics facilities, circulating pumps and so on. The main technical parameters were: Aquacultural water of the system were 2 800 m3, the designed cultural density load was 2.5 kg/m3, the circulated flow rate was 285 m3/h, the water supply was 3.5 m3/h and the power was 12.15 kW. The system covered an area of 2 750 m2. Application of the system to carry out vannamei breeding experiment in May 2015 lasted for 85 days, the results showed that: pH value of 7.43-8.03, DO of 5.32-7.82 mg/L, ammonia nitrogen value of 0.06-0.54 mg/L, the water quality controlled well good. The breeding system load reached to 2.26 kg/m3, feed coefficient was 1.17, the survival rate was 81.3% (by final average body weight), which achieved a efficient growth results. The single crop profited 33 400 yuan, which accessed good economic returns. The set values (expected value) of main parameters such as water temperature, pH value, dissolved oxygen and aquaculture load were in good agreement with the measured values, and the deviation range between set value and the measured value was 4%-10.3%. The results provide a reference for the higher place pond culture model of sustainable development.