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1.
以膨胀珍珠岩为滤料对工厂化养鱼池的排出水进行过滤,去除其中的悬浮固体,同时利用组合式生物填料吸附并降解水中的有机物.采用这种物理过滤和生物膜法相结合的方法净化处理养鱼水,当水循环系统处于稳定状态时,可以使处理后的水质各项指标达到渔业用水水质标准,从而实现养殖用水的循环使用. 相似文献
2.
采用多孔聚酯泡沫块固定里氏木霉大三相流化床固定化反应器中同时产酶同时降解壳聚糖，结果表明，通过控制降解时间可以得到不同平均聚合度的降解物，在28℃，pH4.8，通气量2.5vvm条件下，重复利用菌丝降解2%（w/v)浓度壳聚糖，每批产生的壳聚糖酶活力平均达到150mU.mL^-1以上，壳聚糖平均降解率为72%以上，利用此固定化反应器，在45天内连续进行15批同时产酶降解试验，结果发现壳聚糖酶活和壳聚糖降解率能保持稳定。 相似文献
3.
工厂化养鱼中氧气锥的增氧规律 总被引：2，自引：0，他引：2
控制养殖水体溶氧是工厂化养鱼水处理主要技术之一.介绍一种工厂化养鱼氧气锥的结构、原理及增氧效果.为了掌握氧气锥增氧规律,对氧气锥进行了氧气流量单因素等差梯度试验.结果表明,在循环水流量为65 m3/h,水温24.5℃,氧气流量为0,1,2,……,10 L/min的条件下,溶氧与氧气流量回归方程为y=0.100 9x2+0.059x+5.958 8(r=0.992 7);根据物料平衡原理,推算出氧气锥的最大氧气利用率为84.56%;在最大氧气利用率的条件下,依照尼罗罗非鱼的耗氧率计算模式,推算出工厂化养鱼系统需配置氧气锥的台数. 相似文献
4.
为提高对工厂化鳗鲡精养殖水体水质的原位改良能力和养殖尾水的氮磷减排，通过对鳗鲡养殖尾水处理池中采集的淤泥进行分离筛选，获得一株高效好氧反硝化聚磷菌。经16S rDNA序列鉴定分析，确定为坦氏不动杆菌(Acinetobacter tandoii),将其命名为坦氏不动杆菌PP-1。开展了菌株PP-1对鳗鲡养殖水质总磷和硝酸盐氮降解效果的试验，结果显示水力停留时间在12 h、24 h的总磷降解率分别达到56.31%和81.82%,硝酸盐氮降解率分别达到65.5%和90.37%。开展了菌株PP-1在美洲鳗鲡工厂化养殖中的应用研究，结果显示，水力停留时间在24 h的总磷和硝酸盐氮的降解率分别达到58.8%和56.1%。研究表明，坦氏不动杆菌PP-1有助于降低美洲鳗鲡养殖水体的总磷和硝酸盐氮质量浓度，促进美洲鳗鲡的生长，同时具备良好的应用安全性。该研究为解决鳗鲡养殖水体中的氮磷同步降解问题提供了新的参考，具有重要的应用价值。 相似文献
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蛋种鸡不同产蛋阶段种蛋对孵化效果影响的研究 总被引：1，自引：0，他引：1
本试验选择了４个不同产蛋阶段的鸡群,分别收集种蛋进行孵化。结果显示：不同产蛋阶段的种蛋与其受精率、受精蛋孵化率和健雏率有着密切的关系。以产蛋高峰期的种蛋孵化效果最优,高峰后期次之,再次为高峰前期,产蛋后期为最差。 相似文献
6.
高容量鱼池初级生产力和产氧、耗氧值特点的初步研究 总被引：1，自引：0，他引：1
本文总结了亩净产为1500～2600公斤的高容量(高载鱼晕)鱼池水域初级生产力和产氧、耗氧值的特点，在透明度为28～40厘米的条件下，“水呼吸”耗氧量占31．3％；池鱼呼吸（考虑到活动和摄食生长因素)占61．8％，与一般精养鱼池“水呼吸”耗氧要占约70％，池鱼占20％和其它因子的耗氧占10％的情况有着明显的区别；高容量鱼池在透明度为35～40厘米时，2米深水柱毛产氧量约等于水呼吸耗氧晕，而一般精养鱼池2米深水柱的毛产氧量要小于水呼吸耗氧量。由此证明，高容量鱼池所采取的排除底层污泥的池塘改造措施以及经常排除底层负氧水、及时添补新鲜水的水质控制技术，对于减少“水呼吸”耗氧量，改善池水溶氧条件是有效的。高容量鱼池由于载鱼量高，仅依靠水体的产氧，溶氧的收、支还不平衡，因此，使用增氧设备自然是重要的增产措施。 相似文献
7.
近几年，南方杂色鲍工产化养殖受病害困扰，养殖海区水质出现富营养化，共栖生物种群增加，病因较为复杂。工厂化养殖杂色鲍鱼采用2m以下海区砂层水，配合陆上过滤系统，或采用循环水生态系统工厂化养殖，能大幅度减少有害生物和污着生物，科学交替使用消毒丹和有益菌，能提高工厂化杂色鲍养殖成活率15～20％，减轻越冬时杂色鲍大量死亡的威胁。 相似文献
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本文报道了将养鱼池与生物净化池、沉淀池相结合，并利用鼓风机、增氧机增氧、锅炉加热提高水温、自动控制等技术措施，实现每平方水面载鱼量６０公斤、鱼池年利用二茬，平均每亩净产６万公斤的集约化养鱼技术研究。 相似文献
10.
研究了不同疏浚泥浆浓度和驯养时间对鱼种耗氧率变化的影响。试验结果表明，在一定泥浆浓度范围内，鱼的耗氧率与水体含泥量呈线性相关。在泥浆浓度为０．８００ｇ／Ｌ或０．９６０ｇ／Ｌ水中饲养１０ｄ左右，鱼耗氧率可调节到正常水平，但若进一步延长驯养时间，耗氧率则逐渐下降，两者之间呈显著负相关关系。 相似文献
11.
Divas Karimanzira Karel Keesman Werner Kloas Daniela Baganz Thomas Rauschenbach 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):470-486
ABSTRACTIn this article, optimal control methods based on a metabolite-constrained fish growth model are applied to the operation of fish production in an aquaponic system. The system is formulated for the twin objective of fish growth and plant fertilization to maximize the benefits by optimal and efficient use of resources from aquaculture. The state equations, basically mass balances, required by the optimization algorithms are given in the form of differential equations for the number of fish in the stock, their average weight as mediated through metabolism and appetite, the water recirculation and waste treatment, hydroponic nutrient requirements and their loss functions. Six parameters, that is, water temperature, flow rate, stock density, feed ration size per fish, energy consumption rate and the quality of food (percentage of digestible proteins) are used to control the system under dynamic conditions. The time to harvest is treated as a static decision variable that is repeatedly adjusted to find the profit-maximizing solution. By modeling the complex interactions between the economic and biological systems, it is possible to obtain the most efficient decisions with respect to diet composition, feeding rates, harvesting time and nutrient releases. Some sample numerical results using data from a tilapia-tomato farm are presented and discussed. 相似文献
12.
Emmanuelle Roque d&#x;orbcastel Jean-Paul Blancheton Alain Belaud 《Aquacultural Engineering》2009,40(3):135-143
The objective was to compare water quality and fish growth and mortality in a pilot scale recirculating system (RS) and a control tank in flow through system (FTS). The RS was designed after the Danish Model Trout Farm and operated with a make up water renewal rate of 9 m3 kg-1 of fish produced. RS water quality did not decrease significantly with water flow rate decrease in the RS. During the experiment, the RS water treatment system presented solids removal efficiency of 59.6 ± 27.7% d−1, ammonia oxidation of 45 ± 32 g m−3 d−1, oxygenation yield of 392 ± 132 g of O2 kWh−1 and CO2 degassing of 23.3 ± 11.9% pass−1. In the RS, nitrite concentration was 0.15 ± 0.07 mg l−1, close to the toxicity threshold; a N2 supersaturation phenomenon was measured, probably due to the air injection depth. The biofilter and sedimentation area management has to be improved to avoid organic matter decomposition and release of dissolved elements. Even if no N2 over-saturation apparent effect on fish performance and aspect were detected, the airlift depth has to be modified in the case of industrial development of the RS. Some improvements of the water treatment system, especially on the airlift and sedimentation area, are suggested.Concerning fish growth, no significant differences were observed between the RS and the FTS. No pathologies were detected and cumulative mortality rates (0.1%) were similar to the farm's usual data. There were no significant effects of water flow rate decrease in the RS on fish performance and energy savings were recorded to be 0.7 kWh kg−1 of fish produced between RS1 and RS2. The global energy cost of the RS was 3.56 kWh kg−1 of fish produced (0.107 € kg−1 of fish produced). Even if the energy consumption of the water treatment system can be improved, the results confirm that recirculating system can be used for industrial trout on growing, without fish performance deterioration. 相似文献
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Recirculating aquaculture systems (RAS) are often designed using simplified steady-state mass balances, which fail to account for the complex dynamics that biological water treatment systems exhibit. Because of the very slow dynamics, experimental development is also difficult. We present a new, fast and robust Modelica implementation of a material balance-based dynamic simulator for fish growth, waste production and water treatment in recirculating aquaculture systems. This simulator is used together with an optimization routine based on a genetic algorithm to evaluate the performance of three different water treatment topologies, each for two fish species (Rainbow trout and Atlantic salmon) and each in both a semi-closed (no denitrification) and a fully recirculating version (with denitrification). Each case is furthermore evaluated at both saturated and supersaturated oxygen levels in the fish tank influent. The 24 cases are compared in terms of volume required to maintain an acceptable TAN concentration in the fish tank. The results indicate that the smallest volume is obtainable by introducing several bypass flows in the treatment system of a semi-closed RAS and that the gains can be significant. We also show that recycling already treated water back upstream in the treatment process degrades performance and that if one wishes to have a fully recirculating system with minimal water exchange, then the flows of oxygen, carbon and nitrogen must be carefully considered. For several of the cases, no optimum with denitrification could be found. We thus demonstrate that the best configuration and operation strategy for water treatment varies with the conditions imposed by the fish culture, illustrating the complexity of RAS plants and the importance of simulations, but also that computer-driven optimal design has the potential to increase the treatment efficiency of biofilters which could lead to cheaper plants with better water quality. 相似文献
14.
Airlift pumps are commonly used in aquaculture systems to circulate water and maintain critical gas levels. In production marine reuse systems, a significant decrease in airlift pump flowrate was visually observed immediately after feeding. In experimental systems without fish, it was found that feed additions of less than 10 mg/L decreased water flow by as much as 78% for diffuser injectors but only 10% for pumps with direct air injection. For both injector types, feed impact diminished over several hours but persisted longer in seawater than in freshwater. Video footage revealed increasing bubble coalescence with the addition of feed. The decrease in pump flow is likely attributed to water property changes due to compounds leaching out of the feed. This decrease in pumping rate has the potential to negatively impact water quality, system performance, and fish health. 相似文献
15.
An optimal flow domain in culture tanks is vital for fish growth and welfare. This paper presents empirical data on rotational velocity and water quality in circular and octagonal tanks at two large commercial smolt production sites, with an approximate production rate of 1000 and 1300 ton smolt/yr, respectively. When fish were present, fish density in the two circular tanks under study at Site 1 were 35 and 48 kg/m3, and that in four octagonal tanks at Site 2 were 54, 74, 58 and 64 kg/m3, respectively. The objective of the study was twofold. First, the effect of biomass on the velocity distribution was examined, which was accomplished by repeating the measurements in empty tanks under same flow conditions. Second, the effect of operating conditions on the water quality was studied by collecting and analysing the water samples at the tank’s inlet and outlet. All tanks exhibited a relatively uniform water velocity field in the vertical water column at each radial location sampled. When fish were present, maximum (40 cm/s) and minimum (25–26 cm/s) water rotational velocities were quite similar in all tanks sampled, and close to optimum swimming speeds, recommended for Atlantic salmon-smolt, i.e., 1–1.5 body lengths per second. The fish were found to decrease water velocity by 25% compared to the tank operated without fish. Flow pattern was largely affected by the presence of fish, compared to the empty tanks. Inference reveals that the fish swimming in the tanks is a major source of turbulence, and nonlinearity. Facility operators and culture tank designers were able to optimize flow inlet conditions to achieve appropriate tank rotational velocities despite a wide range of culture tank sizes, HRT’s, and outlet structure locations. In addition, the dissolved oxygen profile was also collected along the diametrical plane through the octagonal tank’s centre, which exhibits a close correlation between the velocity and oxygen measurements. All tanks were operated under rather intensive conditions with an oxygen demand across the tank (inlet minus outlet) of 7.4–10.4 mg/L. Estimates of the oxygen respiration rate in the tank appears to double as the TSS concentration measured in the tank increases from 3.0 mg/L (0.3 kg O2/kg feed) up to 10–12 mg/L (0.7 kg O2/kg feed). Improving suspended solids control in such systems may thus dramatically reduce the oxygen consumption and CO2 production. 相似文献
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Reclaimed water is treated wastewater that has received at least secondary treatment and basic disinfection and is reused for beneficial purposes. The goal of this study was to develop a safe and reliable sustainable aquaculture system for producing stocker fish using reclaimed water in decommissioned wastewater treatment plants (WWTP) in Kentucky. The specific objectives were (1) to monitor paddlefish, Polyodon spathula, growth and survival and water quality in experimental tanks with static or flow‐through reclaimed water, (2) to evaluate the use of decommissioned tanks for large‐scale production of phase II paddlefish, and (3) to biomonitor paddlefish grown in reclaimed water for contaminants. Phase I paddlefish (11 ± 2.6 g) were produced by feeding live Daphnia collected daily from the clarifier tanks with hand‐pulled nets for 27 d. Phase II paddlefish were produced in four replicated 5600‐L experimental tanks with static and flow‐through reclaimed water. Paddlefish from the flow‐through system were significantly larger (199.2 ± 61 g) and had better feed conversion ratios (2.8 ± 2.1) than those from the static system (135.5 ± 51 g; 4.1 ± 1.6). For the large‐scale trial, two 1125 m3 decommissioned digester tanks were stocked with 50,000 paddlefish larvae per tank. One tank was treated as a flow‐through system with reclaimed water flowing at a rate of 280 L/min, while the other tank was treated as a static system where water was just added to replace that lost by evaporation. Survival rate (40%) and weight (194.1 ± 25.4 g) from the flow‐through system were significantly different from those of the static system (31%; 147.1 ± 6.5 g). This difference could be linked to better water quality in the flow‐through systems. Analyses for 38 contaminants were conducted on Daphnia, prepared diets, and paddlefish. All the concentration levels detected were at levels well below the FDA action limits and their permissible limits in edible food. The result from this project showed that paddlefish can be successfully produced in large-scale as stocker fish using reclaimed water in decommissioned tanks at WWTP. 相似文献
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Regardless of the degree of closure of a recirculation system, effluents are produced and replacement water is needed, which limits the possibility of locating a seawater production system away from the shoreline. At the Palavas Ifremer station, in the south of France, a High Rate Algal Pond (HRAP) was operated during several years to treat the effluent from a recirculating aquaculture system before reusing it. The effect of the HRAP-treated water on the recirculation system and on the fish was investigated and the optimal algae growing conditions were defined. The experiments were carried out in three rearing systems: one flow through, one recirculating and one recirculating with a HRAP. The water flow rate, temperature, pH and salinity conditions were similar in all systems.The effect of reusing the HRAP-treated water is very limited (1) on the functioning of the recirculation system and (2) on fish performance, but it allows a significant reduction of the dissolved inorganic nitrogen and phosphorus concentration in the rearing water. HRAP treatment reduced metal accumulation in muscle and liver of RAS fish, except for chromium and arsenic. All biomarkers presented no significant difference between systems, except for Superoxide Dismutase (SOD) and EROD, which showed a higher concentration in RAS and in both recirculating system respectively. 相似文献
19.
Automatic submerging and surfacing performances of model submersible fish cage system operated by air control 总被引：2，自引：0，他引：2
Tae Ho Kim Kyong Uk Yang Kyu Serk Hwang Duck Jong Jang Jung Gyu Hur 《Aquacultural Engineering》2011,45(2):74-86
An automatic, submersible fish cage system using air control was developed and a set of model experiments were conducted to examine the automatic submerging characteristics of the cage. The components of the fish cage consist of a rigid frame assembly with 6 variable ballast tanks and 6 fixed ballast tanks. The variable ballast tanks were used to change the buoyancy characteristics of the system by air control so that the fish cage can either be placed at the surface or submerged. The cage is free to move vertically within a water column by adjusting the weight and the buoyancy with an air control system. The model of this system, with dimensions of 2.20 m in diameter and length and 1.04 m in net cage depth, was constructed to be 1/10 the size of the full-scale system. In the model experiments, the submerging and surfacing characteristics of the cage were regulated with measurements from a water-pressure gauge and a gyroscope incorporated into the automatic control system. Model tests were performed in a still water tank and a large wave tank to develop the algorithm required to control the cage system and to verify the ability of the automatic submersion mechanism to function. The control system was designed so that when the variable ballast tanks were flooded with water, the model descended. To raise the system, compressed air is injected into the tanks by opening the main evacuation valve on the manifold. After the required amount of compressed air is supplied, the main evacuation valves can be shut and as a result, the fish cage becomes buoyant. Measured performance results in a still water tank are then compared with calculations from a previously developed numerical technique. The submerging and surfacing characteristics of the fish cage were relatively similar to the measurements obtained with the physical model experiments using air control. The cage was submerged to a target depth when incidence wave heights were higher than the critical wave height and raised when little wave actions were detected in a wave tank. On the other hand, the cage was placed at the surface when incidence wave heights were the same as the critical wave height or lower. 相似文献
20.
Effects of flow rate on growth performance and welfare of juvenile turbot (Scophthalmus maximus L.) in recirculating aquaculture systems 
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下载免费PDF全文 The effects of flow rate on growth and welfare of juvenile turbot (Scophthalmus maximus L.) were investigated in the present study. Fish with same initial weight (102.5 ± 10.6 g) were subjected to four flow rates, equalling to 0.5, 1, 1.5 and 2 tank volumes per hour in twelve 392 L tanks during 80 days. Results showed that specific growth rate of turbots increased (0.40–0.58% day?1) significantly with promoted flow rate (P < 0.05). Total ammonia nitrogen, nitrite nitrogen, unionized ammonia nitrogen, chemical oxygen demand, total bacteria and total vibrio in tanks were affected significantly by flow rate and accumulations were found in low rate (200 L h?1) (P < 0.05). Free carbon dioxide increased significantly with the increased flow rate and ranged between 4.5 and 13.5 mg L?1 (P < 0.05). Both superoxide dismutase activity and lysozyme activity increased significantly with flow rate (P < 0.05), with ranges of 108.51–131.57 U mL?1 and 551.81–869.28 U mL?1. Serum cortisol showed reversed tendency and ranged between 7.39–19.26 ng mL?1. The principal components analysis suggested that increased flow rate promoted fish welfare. It was concluded that increased flow rate promoted the growth of juvenile turbot, possibly explained by fish welfare differences in combination of health, water quality and serum parameters. 相似文献