技术推广微孔曝气增氧技术

水产养殖常用的增氧设备主要有叶轮式增氧机、水车式增氧机、流射式增氧机、喷水式增氧机和曝气增式氧机等。叶轮式或水车式增氧机主要是设置在水体上层,单独使用很难满足养殖池塘的立体增氧要求,而且能耗相对较高。曝气增氧又可细分为气石曝气增氧和微孔管曝气增氧两种,其区别在于气体的扩散器,     

微孔曝气增氧与叶轮增氧机增氧在南美白对虾池塘养殖的应用比较

试验比较了无油滑片式微孔曝气增氧机与传统的叶轮式增氧机对南美白对虾(Penaeus vannamei)养殖池塘的溶解氧、对虾生长及经济效益的影响.经过4个月养殖试验,结果发现,上午10:00时测得的池塘溶解氧都高于5.9 mg/L,但使用微孔曝气增氧的试验塘溶解氧在养殖过程中高于叶轮式增氧机增氧的对照塘;微孔曝气增氧的池塘,7月份和8月份养殖的南美白对虾的全长分别为6.68 cm和8.98cm,体质量分别为3.19g和9.21 g,显著高于叶轮式增氧的池塘(P＜0.05),但9月份收获时终末体长、体质量与对照塘相比无显著差异;试验塘的饲料系数(1.05)低于对照塘的饲料系数(1.16);微孔曝气增氧提高了亩产量,销售利润(3454.1元/亩)是叶轮式增氧机增氧(2308.1元/亩)的1.5倍.微孔曝气增氧是南美白对虾池塘养殖较好的增氧方式.     

微孔曝气增氧技术

微孔曝气增氧技术采用微孔管道在池塘底部充气增氧，溶氧分布均匀，增氧区域范围广。在主机功率相同的情况下，微孔增氧机增氧能力是叶轮式增氧机的3倍。     

微孔管器水下曝气增氧技术

水体溶氧是好氧水生生物赖以生存的必要条件,水体溶氧的多少,对水质的保持和水产养殖活动的顺利进行非常重要。有人测算,草鱼在溶氧含量为5.5mg/L的水体中生长比在2.7mg/L的水体中生长增肉率提高9.88倍,饲料系数降低5.5倍。为了提高养殖水体溶氧含量,许多地方正在推广微孔管器水下曝气增氧技术。本文就此进行粗略的研究     

微孔曝气增氧机的增氧能力试验

为探究微孔曝气增氧机对氧气的传递效果,从研究增氧能力出发,依据SC/T6009-1999增氧机增氧能力试验方法的标准检测程序,以直径为10m的标准室内水池作为试验平台,试验水温为20℃、气压为101.325kPa、初始溶氧浓度为0mg/L;试验用水为清水,将微孔曝气增氧机与射流式增氧机进行对比试验研究。研究结果表明,微孔曝气增氧机能有效增加水体底部溶解氧,与1.5kW射流式增氧机相比,射流式增氧机的增氧能力平均值为2.4kg/h,微孔曝气增氧机布管长度为20m时,增氧能力平均值为0.25kg/h,布管长度为42m时,增氧能力平均值为0.40kg/h,布管长度为98m时,增氧能力平均值为1.12kg/h,布管长度为200m时,增氧能力平均值为1.55kg/h,所以在目前试验布管密度条件下,增氧能力可以超过射流式增氧机。在进气口压力相同的情况下,微孔曝气增氧机增氧速度随着布管长度增加而增加。     

微孔曝气增氧技术在池塘养殖中的应用研究

对水车式增氧机和微孔曝气增氧做对比试验,结果表明:微孔曝气增氧快,单位时间内增氧效果为水车式增氧机的2.6倍,养殖综合效益比水车式增氧机提高20%~60%。     

微孔增氧技术在淡水池塘养殖中的试验

水体溶解氧是鱼类生存的最基本的条件之一,而水中溶解氧的多少决定着水体容纳生物的密度,传统的水车式、叶轮式增氧机只能提高池塘上层水体溶解氧,却难以为池底提供充足氧气。2009年福建省水产技术推广总站下达了三元区微孔增氧技     

微孔增氧在青虾养殖中的应用

富氧养殖技术是水产健康养殖的重要方式，随着青虾养殖密度的不断提高，单独使用传统的叶轮式增氧机已经不能满足青虾池塘立体增氧的要求。为了充分发掘池塘生产潜力，提高养殖效益，改善水体环境，减少病害的发生，我们采用微孔增氧技术，在青虾养殖中取得较好效果，现将主要技术措施介绍如下：     

微孔增氧技术在青虾养殖中的应用试验

富氧养殖技术是水产健康养殖的重要方式,随着青虾养殖密度的不断提高,单独使用传统的叶轮式增氧机已经不能满足青虾池塘立体增氧的要求。为了充分挖掘池塘的生产潜力,提高养殖效益、改善水体环境、减少病害的发生,我们采用微孔增氧技术,在青虾养殖中取得较好效果,现将主要技术措施介绍如下：     

河蟹池塘养殖底层微孔曝气增氧技术的研究和应用

在2007年-2008年通过底层微孔曝气技术的开发应用,开展了河蟹池塘养殖增氧研究。结果表明养成河蟹规格和单产显著提高,池底增氧技术是河蟹池塘养殖中的关键控制技术,示范区、推广区河蟹的平均规格、单产、毛利比同期常规技术的一般平均水平分别提高了11．37％～36．26％、7．07％～28．49％;50．29％～71．67％、49．11％;177．51％．187．31％、122．2％;养蟹池塘水体DO、NH3-N、NO2—N、TN、TP、COD等主要水质指标明显优于对照池,总体达到地表水环境质量标准（GB3838—2002）Ⅲ类以上,并实现了养殖期内零排放,是一项节水、环保的新型水产养殖技术。     

养殖池塘增氧机制与装备性能比较研究

水产养殖过程中,池塘生态系统可分为自成熟期和人工维持期。在养殖容量提高的情况下,养殖生物呼吸需氧量在不断增加,缺氧条件下有机物分解成有害物质,影响养殖生产。维持池塘生态系统稳定的主要工程机制为:通过上下水层交换、平衡营养元素等方法,强化光合作用,提高营养物质转化规模,提升初级生产力;形成生态增氧为主、机械增氧为辅的高效增氧机制。以中国养殖池塘生态系统为研究对象,分析探讨养殖池塘生态机制、水体溶氧理论、增氧机作用机理、不同类型增氧机的机械性能等,提出了大宗淡水鱼混养池塘及几种典型单养池塘增氧机配置方式,从而为池塘养殖系统增氧机的配置提供技术参考。     

Growth,survival and immune activity of scallops,Chlamys farreri Jones et Preston,compared between suspended and bottom culture in Haizhou Bay,China

We examined the growth, survival and immune response of the scallop, Chlamys farreri, during a 1‐year period in deep water of Haizhou Bay. Scallops were cultured using two methods: (1) in lantern nets at a 5 m depth and (2) in a bottom culture system (sleeves) on the seabed at about a 25 m depth. Shell heights, meat dry weight and immune activities in the haemolymph (superoxide dismutase and myeloperoxidase) were measured bimonthly or quarterly from July 2007 to June 2008. Survival was measured at the end of the study and environmental parameters in the experimental layers were monitored during the experiment. The growth and immune activities of scallops were lower when the water temperature was high, which was consistent with the main mortality occurring in summer. The growth and immunity of scallops were higher in the suspended culture than in the bottom culture during the experiment, with the exception of shell growth during the last study period. Survival of scallops in the suspended culture (54.6±12.3%) was significantly lower than that in the bottom culture (86.8±3.5%) at the end of this study. We conclude from our results that the high mortality of C. farreri can be prevented by culturing them in a bottom culture system before November of the first year, and then transferring them to a suspended culture to improve scallop production.     

Dissolved Oxygen and Aeration in Ictalurid Catfish Aquaculture

Feed‐based production of ictalurid catfish in ponds is the largest aquaculture sector in the USA. Feed has an oxygen demand, and increases carbon dioxide, ammonia nitrogen, and phosphate inputs to ponds. Major sources of oxygen in ponds are phytoplankton photosynthesis and mechanical aeration; the major sink for oxygen is respiration by fish and by microorganisms in the water column and sediment. Dissolved oxygen concentrations decline when respiration exceeds photosynthesis, and the most crucial time for low dissolved oxygen concentration is at night. Mechanical aeration is applied to avoid nighttime dissolved oxygen concentrations from falling below the critical level for catfish of 3 mg/L. Electrically powered paddlewheel aerators are used by most catfish producers. The oxygen‐transfer efficiency of these aerators is known, but calculations of aeration requirement from stocking and feeding rates are not reliable because of variation in phytoplankton abundance and in weather conditions. Dissolved oxygen concentrations must be monitored, and when measurements suggest that nighttime dissolved oxygen concentration will be unacceptably low, tractor‐powered emergency aerators must be operated to supplement dedicated aeration. Dissolved oxygen concentration also is important in hatcheries, and small aeration systems have been developed for hatchery application.     

叶轮式增氧机对鱼池溶氧日变化影响的模拟模型初步研究

针对鲜有鱼池溶氧模型考虑增氧机对鱼池溶氧日变化影响的现实,在传统的描述鱼池水温和溶氧日变化多层模型的基础上,通过分析叶轮式增氧机水跃和液面更新对鱼池多层水体中各能量要素和溶氧变化因子的影响,构建了能反映叶轮式增氧机增氧效果的鱼池水温和溶氧日变化模拟模型.通过实验数据对模型的校参和验证,发现溶氧逐小时模拟值与观测数据的均...     

沿海滩涂养殖水体中溶解氧的变化及其影响因素

为研究沿海滩涂养殖水体中溶解氧的变化规律及其影响因素,２００６～２００７年对江苏射阳盐场滩涂养殖水体中溶解氧的变化进行了调查研究,并与养殖环境中其它因子的关系作了研究分析。结果表明,养殖区溶解氧的含量显著低于非养殖区,夏、秋季溶解氧的含量显著低于春、冬季。相关分析表明,水体中溶解氧的含量与水体中ｐＨ值、盐度、叶绿素ａ、硝酸氮呈显著的正相关,与水体中温度、铵氮、亚硝酸氮、无机磷,底质中硫化物、无机磷都呈显著的负相关。研究结果证实了滩涂大规模的养殖生产是影响水体中溶解氧含量的一个重要因素。     

池塘养殖水体不同水层水质变化研究

为探讨池塘养殖水体时间和空间上的变化特征,在上海市标准化养殖池塘里进行了水质参数监测和分析,研究了池塘上层、中层、下层不同水层的水质变化情况。结果表明:一年中池塘水质呈季节性变化,氨氮均值在9—11月最高,在5月份最低;溶氧均值在9—11月最低,在12月至次年3月最高;pH无明显季节性变化。不同水质参数日变化研究发现,一天中氨氮值在6:00左右最高,在17:00左右最低;溶氧最高值出现在15:00—17:00,最低值在5:00左右;pH在1:00最低,14:00左右最高。养鱼池塘水体有较明显的分层现象,上层、中层、下层不同水层的氨氮、溶氧、pH均有差异。一天中氨氮与溶氧总体呈负相关性(t<0.05),溶氧值升高时氨氮值下降。     

赤潮与对虾养殖业自污行为初探

随着经济的高速增长,全球环境受到严重污染,海洋生态环境污染日益严重,赤潮濒濒发生,给海水养殖业、海洋生态环境、人类健康等带来极大危害。人们对赤潮的研究已开展多年,但主要集中于陆源污染物的研究,对养殖业自身污染形成的赤潮认识不足。本文主要以对虾养殖为例,对赤潮的危害、成因及预防、预测和减灾措施进行了初步探讨。     

不同增氧终端结构对养殖海水增氧效果的影响

比较分析了一定气量下不同增氧终端结构以及一定增氧终端结构下不同通气量强度对养殖海水的增氧效果。试验结果表明,在一定充气量下,随着气石目数的增加其增氧效果越好,即100目依次优于80目和60目;在一定增氧终端结构下,通气量强度越大,水体的增氧效果就越明显。在试验通气量30~150 L/h范围内,于充气量120 mg/L时,100目气石的增氧效果最高;为获得最佳增氧效果,需将气石目数与通气量高低合理搭配。当通气量较低时,应选择目数较小的气石;而通气量较高时,需选择目数较大的气石。探讨最佳增氧效率、氧利用率和动力效率,对节能增效、指导生产实践具有重要的现实意义。     

基于模糊神经网络的池塘溶解氧预测模型

在分析了池塘溶解氧影响因素的基础上,利用模糊神经网络良好的非线性逼近能力建立了池塘溶解氧的模糊神经网络预测模型。神经网络模型如采用常规的BP或其它梯度算法,常导致训练时间较长且易陷入局部极小点,本实验采用快速的粒子群优化算法对模糊神经网络进行训练,收敛速度明显加快。实验结果表明采用该方法预报溶解氧的预测精度较常规BP递推算法的预测精度明显提高,所采用的模型能对溶解氧进行可靠的预测,该方法为研制开发智能水质检测仪以及工厂化养殖工作奠定了基础,对实际生产具有一定的指导意义。     

Vertical Water Circulation Capabilities of an Electric Paddle Wheel Aerator and Dissolved Oxygen Loss Due to Daytime Aeration

ABSTRACT

Vertical water circulation by the paddle wheel aerator was determined by measuring dissolved oxygen profiles in a 3.6-m deep watershed pond during daylight hours, using aerated and non-aerated treatments. The paddle wheel aerator circulated the well-oxygenated surface water to the pond bottom, producing a uniform dissolved oxygen profile in the aerated treatment, while the non-aerated treatment maintained high dissolved oxygen concentrations near the surface with low dissolved oxygen concentrations near the pond bottom. The aerated treatment contained 35.6% less dissolved oxygen than the non-aerated treatment after four hours as a result of operating the aerator during the daytime. The paddle wheel aerator, with a shallow (10 cm) paddle immersion, is effective in vertically circulating water in deeper ponds. However, substantial loss of dissolved oxygen may result from operating the aerator on days with high rates of photosynthesis.