双层浮球生物滤器设计及其水产养殖水处理性能试验

工厂化水产养殖水体的处钾主要包括增氧、分离（分离固体物和悬浮物）、生物过滤（降低BOD、氨氮和亚硝酸盐）、曝气（去除二氧化碳等）和杀菌消毒等处理过程。其中,悬浮物和氨氮去除是主要技术难点。自20世纪80年代,各国学者深入研究了固定滤床和流化滤床、喷淋滤床和浮球生物滤器（bead filter）等悬浮物和氨氮综合处理装置的性能。     

其他

940764 充气法分离水中固体悬浮物=Sus-pended—solids removal by foam fractionation[刊,英]/Shulin C//Prog.Fish-Cult..-1993,55(3).-69～75本文利用气泡凝聚固体的特性,设计了充气分离器,收集循环养鱼系统中的固体悬浮物。用计数器推算颗粒的大小。分离固体悬浮物的效果,与排除可分解性固体相同。所排除的固体物质,绝大多数是有机物,直径小于30微米。(刘澧津)     

泡沫分离法在罗非鱼半咸水循环水系统中的水质净化效果

机械气浮机通过产生大量丰富细密的雾化气泡,微气泡在垂直上升过程中将水中的悬浮物质粘附去除。通过测定泡沫分离器前后水质指标的变化情况,研究机械气浮装置在半咸水循环水养殖系统中的水质净化效果。结果表明,以机械气浮装置作为主要物理过滤水处理环节,并与鱼池双排水技术结合,在半咸水工况下可以承担主要的物理过滤功能,其总悬浮物(TSS)、化学耗氧量(COD)、总氮(TN)、总磷(TP)和色度的平均去除率分别可达(37.19±12.04)%、(21.89±6.19)%、(30.56±3.62)%、(19.38±5.27)%和(18.66±5.56)%。通过淡水鱼咸水化与泡沫分离技术的有机结合,可有效解决淡水鱼封闭循环水养殖中微小颗粒悬浮物的技术难题,是一种行之有效的方法。     

新型水处理技术在水产养殖中的应用

<正>一、当前应用的水产养殖废水处理技术1.物理化学处理法(1)固-液分离技术:固-液分离技术主要是针对养殖废水中悬浮固体去除的废水处理技术,按照悬浮颗粒物的特性(密度、颗粒的大小),又可分为机械过滤和重力分离两种技术。机械过滤是水产养殖系统中用来进行固-液分离的主要手段,通常可去除粒径60~200微米的颗粒物。常用的机械过滤设备有固定筛、旋转筛、振动筛、砂滤器,其中砂滤器是采用填充一定粒径的介质     

工厂化循环水养殖预排污系统与排水系统研究与设计

一种新型的用于工厂化养殖固体颗粒预去除系统研制成功.该水处理系统最大的特点是:不需要任何的外在动力.该系统主要包括两部分:(1)靠养鱼池外置竖管设定水位来实现自动排水的排水系统;(2)靠养鱼池排水管口附近放置的筛网和转动水轮上的毛刷的共同作用,去除养殖循环水中的较大的固体颗粒(残饵和粪便)的排污系统.在去除过程中,耗水率均在5%以内;固体颗粒的去除率也均在80%以上.     

一种工业化水产养殖的水质处理装置

设计和研制的SY水质处理装置采用加压强化增氧的工艺使水中含氧量瞬时达到过饱和，结合泡沫分离技术去除水中的悬浮物和胶状物质，并采用生物接触氧化技术消除水中的氨氮等有害物质，达到净化水质的目的。将之运用于工业化养鱼的再循环系统中，在高密度养殖的试验中取得了较好的效果。     

生态清洁型工厂化循环水养殖半滑舌鳎技术

<正>固体颗粒物是循环水养鱼系统主要污染物质,也是病原体的生存基础,养殖系统颗粒物分离率较低,养鱼系统不清洁导致水质污染、病害频发,是目前循环水养鱼效果不理想主要原因之一。针对这一问题,笔者研究的生态清洁型封闭式循环水养鱼方法,从预防病害发生入手,应用平流分离、旋流分离和生物滤池过滤等固液分离技术,同时增加紫外线消毒和液态     

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。     

弧形筛在工厂化水产养殖系统中的应用及其净化效果

通过对养殖池排出污水经过弧形筛前后几个重要水质指标(溶解氧、pH、盐度、氨氮、亚硝酸氮、硝酸氮、化学需氧量、生化需氧量、悬浮物)的变化,评价了弧形筛对废水中固体废物的净化作用.结果表明,弧形筛有效去除了废水中的固体颗粒,筛除率高达90%,起到了很好的阻截固体污染物的作用,同时增加了水体的含氧量,提高了pH值,降低了化学需氧量(COD),为后续的水处理减轻了负荷.     

利用循环水和人工湿地技术改建鳗鲡精养池试验

利用循环水处理技术和人工湿地净化技术构建的双循环系统模式,对福建地区鳗鲡(Anguillidae)精养池系统进行技术改进研究.结果表明:该模式在养殖密度约14.3 kg/m3时,养殖水体氨氮平均值为1.13 mg/L,水体溶解氧基本保持在6 mg/L以上,固体悬浮物浓度平均为13.6 mg/L,菌落总数平均为777 CFU/mL,仅为对照池的58%,其他水质指标也明显优于对照池;经过100 d的养殖,欧洲鳗鲡平均体重由32.5 g增至184.5 g,平均成活率92.7%.并联式双循环水处理工艺在鳗鲡养殖中具有水质处理效果好、改建和运行低廉等优点,适合我国南方地区鳗鲡精养池模式的循环水化改造.     

Determining design parameters for recovery of aquaculture wastewater using sand beds

Design information for the use of sand beds to remove suspended solids from wastewater discharged from recirculating aquaculture systems (RAS) was developed. Wastewater from a commercial RAS tilapia farm with 2% total solids and 1.6% total suspended solids (TSS) was applied to sand columns to determine infiltration rates and phosphorus capture. Various hydraulic loading rates and drying periods between application events were evaluated. Infiltration rates stabilized after five application events to 3.5 cm/day (S.D.=1.7). Practically, all suspended solids were captured at the top of the columns, creating the primary resistance to infiltration. Concrete sand removed approximately 93% of the soluble phosphorous in the wastewater and wollastonite, an economical aggregate alternative to sand, removed at least 98%. A modified Darcy equation is presented to predict infiltration based upon TSS and the number of sequential applications.     

Assessment of the use of precipitating agents and ceramic membranes for treatment of effluents with high concentrations of nitrogen and phosphorus from recirculating aquaculture systems

Following the culturing of post‐juvenile African catfish, wastewaters were purified using single and integrated processes. Iron coagulant (IC), aluminium coagulant (AC), lanthanum modified bentonite (LMB) and ceramic membranes (NF – nanofiltration) were each tested in single processes, while the combination of IC + NF and AC + NF were used in the integrated process tests. Among the single processes, membrane filtration was the most effective in purifying the aquaculture effluent. The total suspended solids (TSS) were removed entirely and there was a near‐complete removal of turbidity (99.2%), as well as effective removal of Al and Fe (80.8% and 67.4% respectively). Precipitating agents overall removed TSS most faithfully, from 37.5% removal with AC, through 50.2% with IC, to 62.3% with LMB. Using integrated processes, the highest removal efficacy was recorded for TSS (100%) and turbidity (99.7% – IC + NF; 99.9% – AC + NF). Additionally, integrated processes attained a 96.8%–98.4% removal of NO₂^‐‐N. This study confirms the possibility of using IC, AC and LMB in chemical purification of effluents from recirculating aquaculture systems (RAS). However, due to their low removal efficacy for nitrogen and phosphorus, it is preferable to use NF or integrated processes – membrane filtration combined with chemical precipitation, methods which proved to be most effective for water purification in RAS.     

Screening and evaluation of polymers as flocculation aids for the treatment of aquacultural effluents

As environmental regulations become more stringent, environmentally sound waste management and disposal are becoming increasingly more important in all aquaculture operations. One of the primary water quality parameters of concern is the suspended solids concentration in the discharged effluent. For example, EPA initially considered the establishment of numerical limitations for only one single pollutant: total suspended solids (TSS). For recirculation systems, the proposed TSS limitations would have applied to solids polishing or secondary solids removal technology. The new rules and regulations from EPA (August 23, 2004) require only qualitative TSS limits, in the form of solids control best management practices (BMP), allowing individual regional and site specific conditions to be addressed by existing state or regional programs through NPDES permits. In recirculation systems, microscreen filters are commonly used to remove the suspended solids from the process water. Further concentration of suspended solids from the backwash water of the microscreen filter could significantly reduce quantity of discharge water. And in some cases, the backwash water from microscreen filters needs to be further concentrated to minimize storage volume during over wintering for land disposal or other final disposal options. In addition, this may be required to meet local, state, and regional discharge water quality. The objective of this research was an initial screening of several commercially available polymers routinely used as coagulation–flocculation aids in the drinking and wastewater treatment industry and determination of their effectiveness for the treatment of aquaculture wastewater. Based on the results of the initial screening, a further evaluation of six polymers was conducted to estimate the optimum polymer dosage for flocculation of aquaculture microscreen effluent and overall solids removal efficiency. Results of these evaluations show TSS removal was close to 99% via settling, with final TSS values ranging from as low as 10–17 mg/L. Although not intended to be used for reactive phosphorus (RP) removal, RP was reduced by 92–95% by removing most of the TSS in the wastewater to approximately 1 mg/L–P. Dosage requirements were fairly uniform, requiring between 15 and 20 mg/L of polymer. Using these dosages, estimated costs range from $4.38 to $13.08 per metric tonne of feed.     

The performance and impact of a bubble-wash bead filter in a recirculating green water larval culture system for delta smelt (Hypomesus transpacificus)

Delta smelt are cultured at the UC Davis Fish Conservation and Culture Lab (FCCL) for research purposes. The culture systems used are based on recirculation technology to ensure optimum water quality for the fish at each life stage. Larval culture takes place in recirculation systems with green water to which a Nannochloropsis algal concentrate is added to maintain a turbidity of approximately 9 NTU. A bubble-wash bead filter is used to remove total suspended solids (TSS) from the recirculation system. The performance of the bubble-wash bead filter has been evaluated by testing the TSS and particle size distribution in two parallel systems operated in the same way. The need for bubble-wash bead filter backwashing and the impact of the backwash method were evaluated also.The results show that the bubble-wash bead filter removed a great deal of the TSS, including the algae added to maintain the turbidity. An improper backwash method could result in a short term but significantly high TSS peak in the system immediately after the backwash event. Testing over an extended filtration period with a prolonged backwash interval showed that the TSS in the system remained stable up to 150 h post backwash, at which time it increased rapidly. The TSS accumulation in the system with a bubble-wash bead filter that was not backwashed was greater than that in a parallel system without a bubble-wash bead filter. No significant mortality increase was found in the system without a bubble-wash bead filter for 34 days, which provides a possible alternative in order to lower the rearing cost. Nevertheless, there are benefits of using a bead filter, and these are discussed in the paper.     

Solids removal at a recirculating salmon-smolt farm

The objective of this study was to determine the solids separation efficiency of the four swirl separators and the drum filter within one of the water recirculation systems (RAS) of a salmon-smolt hatchery. Water flowrates and concentrations of total suspended solids (TSS) within the RAS were measured weekly over 5 weeks in 2004 and 4 weeks in 2005. During the study, the hydraulic retention time in the tanks was 2.8 h and the feed rate ranged between 0.16 and 0.84 kg/m³ of make-up water. The system volume replacement rate and the water flow recycle rate were respectively 21%/day and 96% in 2004, and 50%/day and 91% in 2005. A mathematical model was developed to determine the transient concentration of fine particles in the recirculation loop. By fitting the predictions of the model to the measured TSS concentrations, it was determined that about 15% of the waste generated within the RAS (assumed equal to 20% of daily feed rate) was removed by the system overflow water. Using this information and TSS data from the backwash water of the drum filter, it was calculated that the swirl separators and drum filter removed respectively 63% and 22% of the waste solids rejected by the fish.     

Hydroponic plate/fabric/grass system for treatment of aquacultural wastewater

Hydroponic plants can efficiently absorb and uptake soluble compounds in wastewater but they have low abilities to remove suspended solids due to the lack of culture media to trap solids. This paper presented an improved hydroponic method for effective treatment of the wastewater from the backwash of recirculating aquacultural systems. The ryegrass (Lolium perenne Lam) was cultured with improved media consisting of perforated plastic plates and several layers of unwoven cotton fabric. The plate/fabric/grass cells with one, three, five, and seven layers of fabric were studied. After one vertical filtration pass through the cells, the removals were 48, 59, 60 and 63% for total solids (TS), 48, 58, 63 and 69% for volatile solids (VS), and 4, 7, 14 and 25% for suspended solids (SS), respectively, for different cells with one, three, five, and seven layers of fabric. It was found that increasing the number of vertical filtration passes through the cells improved the solids removal. The 1-day treatment in the recycling irrigation and treatment system with five cells ( = 0.8 m² grass) removed 66% TS, 71% VS, and 91% SS, and absorbed 72% total nitrogen (TN), 80% total phosphorus (TP), 63% chemical oxygen demand (COD), and 85% total ammonia nitrogen (TAN). This hydroponic plate/fabric/grass system is a simple and efficient technology for the effective eco-treatment of aquacultural wastewater with relatively high concentrations of suspended solids.     

Screening and evaluation of polymers as flocculation aids for the treatment of aquacultural effluents

As environmental regulations become more stringent, environmentally sound waste management and disposal are becoming increasingly more important in all aquaculture operations. One of the primary water quality parameters of concern is the suspended solids concentration in the discharged effluent. For example, EPA initially considered the establishment of numerical limitations for only one single pollutant: total suspended solids (TSS). For recirculation systems, the proposed TSS limitations would have applied to solids polishing or secondary solids removal technology. The new rules and regulations from EPA (August 23, 2004) require only qualitative TSS limits, in the form of solids control best management practices (BMP), allowing individual regional and site specific conditions to be addressed by existing state or regional programs through NPDES permits. In recirculation systems, microscreen filters are commonly used to remove the suspended solids from the process water. Further concentration of suspended solids from the backwash water of the microscreen filter could significantly reduce quantity of discharge water. And in some cases, the backwash water from microscreen filters needs to be further concentrated to minimize storage volume during over wintering for land disposal or other final disposal options. In addition, this may be required to meet local, state, and regional discharge water quality. The objective of this research was an initial screening of several commercially available polymers routinely used as coagulation–flocculation aids in the drinking and wastewater treatment industry and determination of their effectiveness for the treatment of aquaculture wastewater. Based on the results of the initial screening, a further evaluation of six polymers was conducted to estimate the optimum polymer dosage for flocculation of aquaculture microscreen effluent and overall solids removal efficiency. Results of these evaluations show TSS removal was close to 99% via settling, with final TSS values ranging from as low as 10–17 mg/L. Although not intended to be used for reactive phosphorus (RP) removal, RP was reduced by 92–95% by removing most of the TSS in the wastewater to approximately 1 mg/L–P. Dosage requirements were fairly uniform, requiring between 15 and 20 mg/L of polymer. Using these dosages, estimated costs range from $4.38 to $13.08 per metric tonne of feed.     

Water quality,waste production,and off-flavor characterization in a depuration system stocked with market-size Atlantic salmon Salmo salar

Land-based Atlantic salmon, Salmo salar, grow-out facilities utilize depuration to remediate off-flavor. Water used in this process is either discharged or repurposed as supply water in recirculating aquaculture systems (RAS). Both approaches require an understanding of water quality and waste production for water treatment decisions and compliance with pollution discharge standards; however, these data were lacking. Therefore, a study was carried out to characterize these parameters. To begin, 311 salmon (5–6 kg) originally cultured in freshwater RAS were stocked at 100 kg/m³ in an 18 m³ depuration tank. Feed was withheld 1 day before transfer and throughout the 7-day study period. Hours after stocking, total suspended solids (TSS), total phosphorus (TP), and total ammonia nitrogen (TAN) levels spiked, and concentrations declined thereafter. Delta TSS and TP were negligible by the end of the trial; however, TAN plateaued, indicating that salmon began to catabolize somatic tissue in the absence of feeding. Geosmin and 2-methylisoboreol levels in water and fish were low throughout the study. This research indicates that residual waste production occurs while depurating Atlantic salmon. Procedural refinements and recommendations were gleaned including locality for introducing depuration system water within RAS and extension of the feed withholding period before depuration.     

Feasibility of using foam fractionation for the removal of dissolved and suspended solids from fish culture water

The results of an experimental study on the feasibility of foam fractionation to remove suspended and dissolved solids from fish culture water are presented. Foam fractionation was found to concentrate volatile solids (VS), total Kjeldahl nitrogen (TKN), and total suspended solids (TSS) in the foam condensate. Foam fractionation did not concentrate fixed solids (FS). Air flow rate and overflow height were found to be important operational factors in determining condensate concentration, condensate production and removal rates of VS. Predictive regression equations are presented to predict the performance of a typically configured foam fractionation device. Measurements of TKN and TSS in the foam condensate and fish culture water were well correlated with VS, indicating that VS measurements can be used to predict concentrations and removal rates of both TKN and TSS from fish culture waters that are similar to those analyzed.     

Hydroponic plate/fabric/grass system for treatment of aquacultural wastewater

Hydroponic plants can efficiently absorb and uptake soluble compounds in wastewater but they have low abilities to remove suspended solids due to the lack of culture media to trap solids. This paper presented an improved hydroponic method for effective treatment of the wastewater from the backwash of recirculating aquacultural systems. The ryegrass (Lolium perenne Lam) was cultured with improved media consisting of perforated plastic plates and several layers of unwoven cotton fabric. The plate/fabric/grass cells with one, three, five, and seven layers of fabric were studied. After one vertical filtration pass through the cells, the removals were 48, 59, 60 and 63% for total solids (TS), 48, 58, 63 and 69% for volatile solids (VS), and 4, 7, 14 and 25% for suspended solids (SS), respectively, for different cells with one, three, five, and seven layers of fabric. It was found that increasing the number of vertical filtration passes through the cells improved the solids removal. The 1-day treatment in the recycling irrigation and treatment system with five cells ( = 0.8 m² grass) removed 66% TS, 71% VS, and 91% SS, and absorbed 72% total nitrogen (TN), 80% total phosphorus (TP), 63% chemical oxygen demand (COD), and 85% total ammonia nitrogen (TAN). This hydroponic plate/fabric/grass system is a simple and efficient technology for the effective eco-treatment of aquacultural wastewater with relatively high concentrations of suspended solids.