用配合饲料饲养牙鲆试验

在封闭式循环水养殖系统中,用软颗粒配合饲料投喂牙鲆,经过157天的饲养,牙鲆的尾相对增重率为136%,平均饲料系数为1.51,牙鲆增重1kg所需饲料成本为10.87元,养殖单产为25kg/m3。     

养殖用水重复利用过程中悬浮固体物的性质及控制

颗粒物不仅对养殖对象有直接影响,也会影响到其它水处理单元的效率,是水产养殖水体重复利用和排放的限制性指标。本文概述了水产养殖水体中固体物质性质的描述指标,根据水产养殖活动的特点对养殖过程中颗粒物的来源途径进行了分析,可以根据水体的投饲量估算需要去除的颗粒产生量;介绍了使用双排管将残饵和粪便尽快地排出养殖池的方法;根据颗粒物的粒径、沉降速率等特征,总结了几种常见的固液分离技术。选择固液分离技术时,需要考虑去除的粒径、水头损失、水力负荷以及总体去除效率,还要考虑是否可能在去除的过程中会把大粒径颗粒碎成小粒径颗粒因而增加总体去除难度。     

循环水养殖系统微细悬浮颗粒的分布规律研究

高密度循环水养殖系统微细悬浮颗粒物(30μm)的去除,是其水环境调控的关键。采用库尔特粒度分析仪分析大西洋鲑(Salmo salar)循环水养殖系统微细悬浮颗粒的时空分布,结果显示:系统中粒径为1～3μm的颗粒占总颗粒数的98.36%,3～15μm的占1.63%,15～30μm的仅占0.01%,系统内微细悬浮颗粒数量、总体积、总表面积的范围分别为(0.36～2.10)×10~6个/mL、(0.97～6.30)×10~(6 )mm~(3 )/mL、(0.24～1.30)×10~(7 )mm~2/mL;颗粒数量分布方面,随着粒径的减小,各样品颗粒数量迅速增加;体积分布方面,颗粒粒径越大,颗粒总体积越大;表面积分布方面,随着粒径的增大,总表面积呈现先减小后增大的趋势;泡沫分离器和浸没式生物滤池都呈现了很强的微细悬浮颗粒截留能力。本研究可为揭示稳定运行的循环水养殖系统的微细悬浮颗粒的分布状况,为选用不同的固液分离技术、提高固体颗粒物的去除效率提供参考。     

漠斑牙鲆内陆淡水池塘网箱养殖试验

通过内陆淡水池塘网箱养殖漠斑牙鲆试验,探索出内陆淡水池塘漠斑牙鲆网箱养殖的模式,总结出养殖过程中应采取的技术措施,25m2网箱总产漠斑牙鲆102.9kg,平均单产4.12kg/m2,漠斑牙鲆平均规格为306.25g/尾,成活率达84%,使池塘产量比往年养殖产量增加5.94%。     

抽屉式生物滤器在漠斑牙鲆循环水养殖中的效果研究

采用自行设计的抽屉式生物滤器应用于漠斑牙鲆(Paralichthys lethostigma)闭合循环水养殖系统,研究其对循环养殖水的处理效果及漠斑牙鲆的增重和饲料利用率的影响。结果表明:经过60 d的循环水养殖,漠斑牙鲆从初始时的(225.4±11.9)g增加到结束时的(337.5±10.3)g,增重率49.97%;试验饲料系数1.06,养殖密度24.1 kg/m3,成活率100%;抽屉式生物滤器对于NH4+-N、NO2--N和COD去除率分别为(10.61±1.88)%、(14.90±3.06)%和(16.11±1.70)%,可满足漠斑牙鲆养殖水体的水质要求。     

循环水养殖系统中旋流颗粒过滤器设计研究

在对颗粒物流体力学分析和计算基础上,设计了直径500 mm、过滤填料层厚度300 mm、水处理量2~8m3/h的旋流颗粒过滤器。该过滤器利用进水所产生旋流和塑料珠填料截留共同作用,可以去除100μm以上可沉淀颗粒物质,截留部分100μm以下悬浮颗粒物质;该过滤器利用鱼池与过滤器液位差产生动力,无需额外机械动力。模拟试验结果表明,当进水TSS为50~70 mg/L、处理负荷在490~671 g/(m3.h)时,颗粒去除率达到(87.2±3.7)%,出水TSS控制在4.5~11.5 mg/L。     

循环水养殖罗非鱼氮收支及对水质影响的初步研究

为提供实际生产理论依据,改良系统水处理工艺,开展循环水养殖系统中吉富罗非鱼氮收支和对水质情况的初步研究。起始养殖密度8 kg/m3,投饲率2%,系统循环量1 m3/h,总水量0.8 m3。试验期间溶解氧大于6 mg/L,pH 7.0～7.2,水温23～25℃。每周监测水质2～3次,监测指标包括氨氮、亚硝酸盐氮、硝酸盐氮,每2周检测1次水中总氮。用凯氏定氮法测定实验前后饲料、试验鱼体、粪便、悬浮颗粒的氮含量。结果显示,摄食氮有50.00±1.50%转化为生长氮,32.61±1.38%转化为排泄氮,17.39±4.0%转化为粪氮;58%的粪氮为悬浮颗粒物,42%为可沉淀颗粒物。     

盐碱地低盐水池塘网箱套养漠斑牙鲆技术

2004-2005年,利用盐碱地低盐水虾池设置网箱套养漠斑牙鲆349.5m2,产鱼3.749t,产虾55.065t,其中2005年虾池设置网箱套养漠斑牙鲆306m2,产鱼3.245t,平均10.6kg/m2,平均全长34.0cm体重527.4g,养殖成活率为90.5%,产虾49.003t,平均408.4kg/667m2,平均规格11.9cm养殖成活率为71.23%。     

盐碱地低盐水池塘网箱套养漠斑牙鲆技术研究

根据漠斑牙鲆(Paralichthys lethostigma)适广温、广盐和较强的抗逆性等优良生态习性,采用地下卤水、盐碱地渗水,通过合理淡水配兑使其适合漠斑牙鲆生理生长需求,在我国中纬度地区利用盐碱地低盐水养殖过洋、暖温性漠斑牙鲆。2004-2005年,利用盐碱地低盐水池塘虾池设置网箱套养漠斑牙鲆349.5m2,产鱼3.749t,产虾55.065t,其中2005年虾池设置网箱套养漠斑牙鲆306m2,产鱼3.245t,平均10.6kg/m2,平均全长34.0cm,体重527.4g,养殖成活率为90.5%,产虾49.003t,平均408.4kg/亩,平均规格11.9cm,养殖成活率为71.23%。虾池设置网箱套养漠斑牙鲆,可充分利用水体空间,促使池塘高产高效,提高养殖经济效益。     

转鼓式微滤机颗粒去除率及能耗的运行试验研究

滤网是转鼓式微滤机的主要工作部件,其网目数(孔径)直接影响转鼓式微滤机的总悬浮颗粒物(TSS)去除效率、反冲洗频率、耗水耗电等.分别选用150目、170目、200目、250目、325目5种规格的不锈钢滤网.利用循环水养殖设施进行转鼓式微滤机滤网网目与TSS去除效率、反冲洗频率、耗水耗电等关系的试验研究.结果表明,200目滤网的技术经济效果最为明显,其TSS去除率达到(54.90±10.42)%,而反冲洗频率为2.1次/h,电耗为6.902 kW·h/d,耗水量为1.68 m3/d.     

Settling velocity and particle size bioengineering parameters gathered from solids generated by wild-caught premature punctuated snake-eels (Ophichthus remiger) reared in a marine prototype recirculating aquaculture system

This research reveals the applied engineering basis for determining the particle size and settling velocity distributions of solids generated while rearing wild-caught premature punctuated snake-eels (Ophichthus remiger) in a prototype recirculating aquacultural system. Settled solids were sampled from the bottom of the rearing tanks, and suspended solids were sampled before filtration within the drum filter and analyzed to characterize their settling velocity and particle size properties. These particle properties are considered bioengineering parameters since they will provide biological information to improve engineering solutions for RAS solids removal processes. The average settling velocity for the settleable solids in the rearing tanks was 2.89 ± 0.02 cm s⁻¹, and the average particle size ranged between 7.32 ± 3.41 and 19.44 ± 8.58 mm. Suspended solids within the drum filters before filtration had an average settling velocity of 0.35 ± 0.11 cm s⁻¹ and it was found that 69.93 % of the particles size was greater than 200 μm, 15.40 % were within the range of 120 μm and 90 μm sizes, and 6.53 % were between 70 μm and 40 μm sizes. The particle physical properties, settling curves, and particle sizes curves obtained from this experience represent valuable information to be used to improve engineering design of solids handling mechanisms, especially in marine land-based systems, and in this case, applied for rearing wild-caught punctuated snake-eels. The present investigation constitutes an advance in the knowledge of applied engineering to the design of a marine aquaculture fattening operation targeted to feed up wild-caught premature punctuated snake-eels to the point of sale or trade.     

循环水养殖系统中的固体悬浮物去除技术

循环水养殖系统(Recirculating aquaculture systems,RAS)中固体悬浮物(Suspended solids,SS)的去除效果直接影响到鱼类生长、生物净化效果、系统配置和运行成本等诸多重要因子。根据固体悬浮物产生、物理特性和分布规律,结合颗粒悬浮物去除工艺特点,对去除技术进行系统研究分析。固体悬浮物源自饲料,密度一般为1.05~1.19 g/cm3,运用重力分离、过滤和泡沫分离等工艺通过预处理、粗过滤和精处理三道工艺步骤,可分别去除不同直径的颗粒物质,在达到合理含量的前提下,获得低能耗、低成本和系统稳定运行的综合效果。固体悬浮物的去除符合目标明确、排出及时和区别对待三原则,去除工艺注重相关技术的优化集成。     

Photosynthetic suspended-growth systems in aquaculture

Standardized evaluation and rating of biofilters for aquaculture should be assessed in the context of the economic efficiency of ecological services (waste assimilation, nutrient recycling, and internal food production) provided by earthen ponds, and the availability and cost of land, water, and electrical energy resources required to support particular classes of production systems. In photosynthetic suspended-growth systems, water quality control is achieved by a combination of natural and mechanical processes. Natural processes include photosynthesis of oxygen, algal nutrient uptake, coupled nitrification–denitrification, and organic matter oxidation; mechanical processes include aeration and water circulation. Ammonia is controlled by a combination of phytoplankton uptake, nitrification, and immobilization by bacteria. Unlike biofilters for recirculating aquaculture systems, unit processes are combined and are an integral part of the culture unit. The important design and operational considerations for photosynthetic suspended-growth systems include temperature effects, aeration and mixing, quantity and quality of loaded organic matter, and fish water quality tolerance limits. The principle advantages of photosynthetic suspended-growth systems are lower capital costs relative to other recirculating aquaculture systems and increased control over stock management relative to conventional static ponds. The main disadvantage is the relatively low degree of control over water quality and phytoplankton density, metabolism, and community composition relative to other recirculating aquaculture systems. Examples of photosynthetic suspended-growth systems include semi-intensive ponds, intensively aerated outdoor lined ponds, combined intensive–extensive ponds, partitioned aquaculture systems, greenwater tanks, greenwater tanks with solids removal, and greenwater recirculating aquaculture systems.     

Analysis of sediment transport modeling using computational fluid dynamics (CFD) for aquaculture raceways

A simulation model to analyze the water flow and sediment transport in aquaculture raceways was developed using a computational fluid dynamics (CFD) software package. The simulation was used to evaluate the efficiency of solids settling in the quiescent zone of existing trout raceways. This efficiency was based on the percentage of solids removed, which corresponds to the percentage of solids introduced into the raceway that settle in it, with settling taking place primarily in the quiescent zone.

The raceway selected for model validation was a rectangular concrete raceway 30.0 m long, 3.0 m wide, 0.9 m deep, with a slope of 0.01. The raceway included a quiescent zone of approximately 5.3 m in length, which was separated from the rearing area by a screen. The water flow rate through the raceway was approximately 0.058 m³/s. Velocity measurements were recorded at 230 stations along the raceway using an acoustic Doppler velocimeter, for comparison with the results obtained from the simulations.

For the purpose of simulating sediment transport, six groups of particles were used to account for the total suspended solids. The sizes of the particles selected were based on an experimentally determined distribution for solids from a similar raceway, and were 692, 532, 350, 204, 61, and 35 μm for Groups 1–6, respectively. The particle density for each size was assumed to be 1150 kg/m³. Values of the percentage of solids removed for the different particle sizes were 100.0% for the largest particles, and 54.7, 0.9, and 0.1% for the three smallest particles, respectively. This methodology of analyzing the raceway sediment transport in terms of its percentage of solids removed based on CFD simulations can also be used to examine raceway design alternatives for improving the particle removal efficiency.     

工厂化水产养殖中的悬浮物处理技术

在循环水工厂化水产养殖中，鱼类的排泄物、残饵、生物团等产生的悬浮物和固体物，增加了水体的浑浊度，堵塞了生物滤器，影响系统的性能和鱼类健康生长。本文根据我国现代渔业发展的趋势，结合国内外有关水产养殖水处理技术的研究成果与发展趋势，论述和分析了目前工厂化水产养殖中悬浮与固体物的物理、化学和生物处理技术及发展趋势，为研发新型水处理设备奠定基础。     

海水工厂化养殖水处理系统的装备技术研究

工厂化养鱼(尤其是全封闭高密度养殖方式)是依靠工艺和设施装备技术的支撑，运用生态学原理及环境条件控制手段进行科学养殖。本文围绕海水工厂化养殖系统主要工艺环节(去除固体废弃物和水溶性有害物质、消毒、增氧、调温、水质测控)中涉及的装备技术和应用进行讨论。     

臭氧处理技术在工厂化水产养殖中的应用研究

臭氧消毒是工厂化水产养殖中水处理的关键技术之一。本文详细介绍了臭氧的物理、化学性质,论述了臭氧制造、水中溶解及水中溶解浓度的检测方法。结合国内外有关水产养殖水处理技术的研究成果与发展趋势,分析了臭氧在工厂化水产养殖水处理中的一些作用和应用特性。介绍了臭氧在工厂化水产养殖中消毒杀菌、氧化有机物、凝聚悬浮物、除臭与除色方面的作用,阐明了臭氧在工厂化水产养殖中的应用前景。     

Settling velocity distribution of bioflocules generated with different carbon sources during the rearing of the river shrimp Cryphiops caementarius with biofloc technology

Controlling the concentration of bioflocs is one of the main concerns in aquaculture systems with Biofloc Technology (BFT). Biofloc accumulation deteriorates the water quality and can negatively affect the production rates of the farmed river shrimp. This study describes and characterizes the settling velocity distribution of bioflocs generated with the addition of two carbon sources (molasses and chancaca) when applying the BFT for the rearing of the river shrimp Cryphiops caementarius. This study revealed that bioflocs generated with different carbon sources have different settling velocity curves. Regarding the mass fraction settling velocities, there were significant differences (P < 0.05) for mean solids fraction at similar withdrawn times between molasses and chancaca. The average settling velocities for bioflocs were 0.1044 ± 0.1224 cm s⁻¹ for molasses and 0.1131 ± 0.1225 cm s⁻¹ for chancaca. Therefore, a settling device operating with a given overflow rate will more efficiently remove bioflocs generated with chancaca than with molasses. The settling velocity curves obtained in this research contain valuable information to select appropriate devices for bioflocs and suspended solids removal in aquaculture systems with BFT.     

An experimental study on nitrification biofilm performances using a series reactor system

Total ammonia nitrogen (TAN) concentration is often a key limiting water quality parameter in intensive aquaculture systems. Removing ammonia through biological filtration is thus the first objective in recirculating aquaculture system design. In this study, the performance characteristics of a steady-state nitrification biofilm were explored using a series of reactors. Four nitrification kinetics parameters were estimated using the data collected from the experimental system, including minimum TAN concentration, half saturation constant, maximum TAN removal rate and maximum specific bacterial growth rate. Experimental data showed that a minimum TAN concentration was needed to support a steady-state nitrification biofilm. For the temperature of 27.2°C, the mean minimum TAN concentration was 0.07 mg/l. For a single substrate-limiting factor, the relationship between TAN removal rate (R) and TAN concentration (S) was represented by an empirical equation [R=1859(S−0.07)/(S+1.93)]. The characteristics of nitrite oxidation were also demonstrated by the experiment system. The results of this study will help to better understand the characteristics of nitrification biofilters applied in recirculating aquaculture systems.     

The effects of different combinations of fixed and moving bed bioreactors on rainbow trout (Oncorhynchus mykiss) growth and health,water quality and nitrification in recirculating aquaculture systems

The effect of bioreactor design on nitrification efficiency has been well studied, but less is known about the overall impacts on water quality. Besides nitrification, submerged fixed bed bioreactors (FBBR) trap fine solid particles, whereas moving bed bioreactors (MBBR) grind solids, possibly increasing solids and particle accumulation in the system. In this experiment, the effects of different combinations of fixed bed and moving bed bioreactors on water quality, solids removal, particle size distribution, fish health based on histopathological changes and nitrification efficiency were studied in laboratory scale recirculating aquaculture systems (RAS) with rainbow trout (Oncorhynchus mykiss). Three set-ups with triplicate tanks were used: 1. two consecutive fixed bed bioreactors (FF); 2. a fixed bed bioreactor followed by a moving bed bioreactor (FM) and 3. two consecutive moving bed bioreactors (MM). Fish performance was not influenced by the design of the bioreactor, specific growth rate (SGR) being between 1.59 and 1.64% d⁻¹ and feed conversion ratio (FCR) between 0.95 and 0.98. Water nitrite concentration was higher in the FF systems compared to FM and MM systems, whereas the average total ammonia nitrogen concentration (TAN) was not influenced by the treatments. Nitrification rate, which was measured in the laboratory, followed the water nitrite levels, indicating highest total ammonium oxidation rates in the MM systems. UV254 absorbance and total organic carbon (TOC) concentrations were higher in the groups with moving bed systems, indicating accumulation of organic substances in the circulating water. The total volume of particles was higher in the MM systems as compared to the FF systems. The total solids balance was similar in all the bioreactor groups, since the removal of solids by the FBBR backwash was compensated by the drum filter in the FM and MM systems. In general, no significant histopathological difference in gill, kidney, heart and liver tissue were observed between the RAS treatment groups and the flow-through treatment.