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Hu Y.,Shanghai Ocean University | Ni Q.,Key Laboratory of Fishery Equipment and Engineering | Ni Q.,Chinese Academy of Fishery Sciences | Wu Y.,Shanghai Ocean University | And 2 more authors.
Procedia Engineering | Year: 2011

The dissolved CO 2 accumulation has become an important factor restricting production in the high-density recirculating aquaculture system in which pure oxygen injection is used. In this paper, a novel CO 2 removal device is designed for the recirculating aquaculture water environment based on the principle of gas exchange. In terms of experiments, the DOE (design of experiment) method is applied to design three factor two level orthogonal experiment, Further, significance effect of gas to liquid ratios (G / L), inlet CO 2 concentration, the water flow rate (Q W) on CO 2 removal efficiency is analyzed. Results show that G/L has the most significant influence on the CO 2 removal efficiency. Influences of the latter two on CO 2 removal efficiency are not apparent. Tests results of G/L effect on CO 2 removal efficiency show that, when G/L=1∼5, CO 2 removal efficiency increases rapidly with the increase of G/L; when G/L=5, CO 2 removal efficiency=80%∼88%; when G/L=8, CO 2 removal efficiency=86%∼92%, when G/L>8, CO 2 removal efficiency increases gently with the increase of G/L. Considering both system energy saving and effective removal of carbon dioxide, G/L=5∼8 is considered to be the best for the aquaculture water CO2 removal device running, CO 2 removal efficiency=80%∼92%. © 2011 Published by Elsevier Ltd.

Zheng J.,Key Laboratory of Fishery Equipment and Engineering | Zheng J.,Jimei University | Wang B.,Jimei University
International Conference on Challenges in Environmental Science and Computer Engineering, CESCE 2010 | Year: 2010

Biomass energy of microalgea is one of the most potential renewable energy. However, over expensive cost, especially the material cost limited its industrialization. Aquiculture wastewater, which is rich in nitrogen and phosphorus, is a main reason for the eutrophication of the surrounding water and is always a problem for the sustainable development of aquaculture. Although many treatments have been used in the field, the expensive cost limited their wide application. Microalgae can utilize the N and P in the wastewater to grow, so it is feasible to purify the wastewater by the microalgae and produce the biomass energy of microalgae from the wastewater. The present paper studied the growth of Chlorella pyrenoidosa in three aquiculture wastewaters and optimized the cultivating condition. The study showed that Chlorella pyrenoidosa could grow in the wastewater from the culture of Cynoglossus semilaevis. Under the condition of pHS, illumination 5000 LX and original inoculation density 0.01 mg/mL, the microalgae had the best growth. Under the optimal condition, the microalgae could eliminate 75.2% active phosphorus, 100% ammonia nitrogen, 84.1% nitrite nitrogen and 52.8% nitrate nitrogen in the wastewater within 11 days, which suggested that the cultivation of microalgae in aquiculture wastewater is a good method for both the exploitation of microalgae biomass energy and the purification of wastewater. © 2010 IEEE.

Jiang T.,Key Laboratory of Fishery Equipment and Engineering | Xu M.,Key Laboratory of Fishery Equipment and Engineering | Zeng Z.,Shanghai Hongcheng Industrial Development Co. | Xu Z.,Chinese Academy of Fishery Sciences
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

At present, tail water generated by the cage culture contains a large quantity of residual feed, feces and other solid waste. If completely discharged, it will cause serious water eutrophication and severe damage for the ecological environment of culture waters. In view of the above question, the waste collection and waste treatment system of cage culture in open waters was developed for the cage culture reducing the tail water discharge and pollution into waters. This system is composed of the waste collecting device for collecting feed bait and fish feces, water supply and drainage system for water circulation into the closable cage, waste collection system for the scale of the cages and closable cages, filter for filtration to feed bait and fish feces and tail water processing system devices five parts. Compared with traditional net cage culture on water pollution, the waste collection and water treatment system of cage culture has four improvements: 1) Adding a dirt collecting bucket in each cage at the bottom, the solid waste together into the bucket, to facilitate the rapid promotion of waste collection. 2) In view of the traditional net cage waste collection, design sewage collection central gathering side lifting bucket apparatus; For a closable cage except with waste collection function, also has a deep water net cage will ascend to, bottom discharge function, with supreme and carry out the way water exchange, pneumatic recoil function, prevent the filter mesh is waste particles blocking. Water door with one-way flow function, prevent the back flow of sewage. 3) For solid waste water after filtration, using an ecological floating bed water pot of economic plants (such as Canna indica L., Acorus calamus L.) and microbial biofilm formation methods, nutrient rich water to fully absorb the water reach the discharge requirements. 4) The whole system adopts compressed air as the power source, centralized collection by using the method of pneumatic lifting implementation of waste water, centralized pneumatic depths can be a closed cage of ascension, as well as an aerated ecological floating bed. Waste collection in the running process of the system, collecting cage precipitation of tail water lifting and the air consumption, pressure has a very close relationship. The system of the waste collection tube with an inner diameter of PVC steel wire spiral reinforced hose 80 mm. 4.5 m under the water and gas water mixing chamber, namely air injection depth of 4.5 m. Through the test, in improving the sludge hopper in tail water, can be found through observation proposed by turbidity of tail water gradually becomes transparent, in this process, the 18 dirt collecting bucket of water statistics, the average sewage collection bucket lifting water is 0.34 m3. The results elaborated through professional transformation of large water cage facilities, constructed from the waste collection, solid-liquid separation, and the breeding of tail water after separation by ecological floating bed hanging membrane technology to physics and a set of ecological treatment system. The system collects the water discharged after treatment, the total phosphorus (TP), ammonia nitrogen (NH3-N), chemical oxygen demand (COD) were 0.305, 0.095, 16.2 mg/L, reached a `freshwater ponds water discharge requirements of ST9101-2007' II class standard. On the ammonia nitrogen and other indicators, the system realizes the standard exhaust culture of the tail water, greatly reducing the concentration of cage aquaculture wastewater to the water discharge. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved.

Yuan K.,Chinese Academy of Fishery Sciences | Yuan K.,Shanghai Ocean University | Zhuang B.,Chinese Academy of Fishery Sciences | Zhuang B.,Key Laboratory of Fishery Equipment and Engineering | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

In order to meet the feeding needs of industrialization aquaculture system, an automatic feeding system was designed and developed applying the monorail technique, the slide rail power supply technique, the ultrasonic positioning technique, the wireless communication technique and the computer software technique. The system was composed of a running system, a power supply system, a feeding equipment and a control system. The feeding system with the function of auto detecting and error alarm could be automatic start and stop, weigh feeding amount and record system operation and feeding data automatically. The running system was mainly composed of a monorail likes a raceway made by H-shape steel, an electric pulley block and an ultrasonic positioning sensor. The four T forging steel rail wheels of the electric pulley block ran on the lower wing plate of H-shape steel. One reflecting plate (80 mm×150 mm) was installed on the monorail corresponded to each rearing tank. The number of each rearing tank was identified by the different distance between each reflecting plate and ultrasonic sensor moving with the electric pulley block. The feeding device comprised a hopper, stepper motor, a gate and four weighing sensors. Four sensors hung up the hopper to the electric pulley block and weighed the mount of the hopper. Opening and closing of the gate was controlled by the changes of the hopper weight. The design calculation showed that when using HW100×100 steel monorail, with the diameter of 0.06 m T forging steel rail wheels, gear ratio 20: 1 gear transmission group and 24 V DC motor to drive the system to moving on the monorail, the motor power must be more than 0.2 kW, speed was 2 000 r/min, output torque requirements must be over 0.58 N · m. The automatic feeding system prototype was designed by Solidworks, and the prototype was tested for the feeding amount accuracy and positioning deviation. The experiments showed that the feeding system was reliable and accurate for feeding with travelling speed 19 m/min, positioning accuracy was in the range of 58-118 mm, bullet storage capacity was 20 kg, feeding capacity was 3 kg/min and feeding accuracy was in the range of 0.5%-2.2%. The system effectively improves the feeding accuracy, reduces the feed waste, abates the labor intensity, and meets the needs of industrialization aquaculture system at the direction of the mechanization and automation. Future improvement will include a smoother monorail without seams and speeding the response of the electrical components to improve the accuracy of feeding and positioning. The results of this research provide a reference for the automatic feeding system design and the related follow-up research.

Gu J.,Key Laboratory of Fishery Equipment and Engineering | Gu J.,Chinese Academy of Fishery Sciences | Gu H.,Chinese Academy of Fishery Sciences | Men T.,Chinese Academy of Fishery Sciences | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

In order to compare the performance indexes of the main mechanical aeration methods in pond culture, the aeration capacity in clean water test, the changes of dissolved oxygen in actual pond and the power efficiency for some kinds of mechanical aeration methods were studied through historical and current data of clean water oxygenation test and field experiments in ponds. The results indicated that the aeration capacity of impeller aerator was 4% and 264% higher than those of paddlewheel aerator and propeller aerator respectively; the power efficiency of impeller aerator was 12.7% and 259% higher than those of paddlewheel aerator and propeller aerator respectively in clean water; the time to achieve the water layer mixing uniformity for impeller aerator was 40% less than those for paddlewheel aerator and propeller aerator, and the increasing values of dissolved oxygen for impeller aerator was 115% and 293% higher than those for paddlewheel aerator and propeller aerator respectively in pond. The comprehensive aeration performance of impeller aerator is higher than that of paddlewheel aerator and propeller aerator, and the propeller aerator has the worst comprehensive aeration performance. The study can provide useful references for the rational application of mechanical aeration methods in pond culture.

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