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.     

海水养殖尾水人工湿地处理系统及其脱氮过程研究进展和展望

利用人工湿地处理海水养殖尾水具有很大的应用前景,其中,脱氮是人工湿地的主要任务之一。基质上栽培的植物和附着的微生物参与的氮循环是人工湿地生物脱氮的主要路径,植物和多种氮代谢菌群在人工湿地内部相互协同与制约,构成了一个复杂的氮代谢网络。海水养殖尾水的高盐度和低碳氮比(C/N)又决定了此类人工湿地独特的处理环境和生物脱氮机制。同时,人工湿地的供氧模式、水力负荷(HRT)、水力停留时间(HLR)等水力条件参数对脱氮效能也有很大影响,对这些指标进行调控和优化,可以提高湿地的整体脱氮性能。本文从海水人工湿地的构建、基质的选取、耐盐植物的筛选、氮循环相关微生物以及运行参数调控四个方面,对近年来海水养殖尾水人工湿地生物脱氮方面的研究进展进行了综述和展望,以期为深入理解海水人工湿地脱氮机制和优化运行方式提供参考。     

利用人工湿地处理池塘养殖废水效果分析

构建表面流和水平潜流人工湿地系统处理水产养殖池塘排放的废水,以减少水产养殖废水对周围水域环境的污染.结果表明,经湿地净化处理后,养殖废水中总氮、总磷、CODMn、氨氮分别从2.32、0.50、14.88、0.61 mg/L降至0.98、0.18、9.72、0.30 mg/L,叶绿素a从369.6 μg/L降至61.78 μg/L,水质明显得到净化.湿地植物存活时组织氮、磷含量明显高于死亡时,湿地植物死亡时梭鱼草、黄菖蒲、小香蒲的组织氮含量分别仅为存活时的18.8%、26.8%、38.1%.湿地植物死亡时收割可去除氮、磷含量分别为11.68 g/m2和4.81 g/m2,再力花去除氮、磷能力最强.在湿地植物死亡前收割能够提高湿地植物吸收所贡献的净化率.     

Settling velocity characterization of aquacultural solids

A top-loading settling column is described and used to characterize the settling properties of the solids in the discharge water from a commercial rainbow trout production facility. Mass-based and phosphorus-based settling curves are presented. The median settling velocity on a mass-basis for the settleable solids was 1.7 cm s⁻¹. The median settling velocity for the settleable phosphorus was 1.15 cm s⁻¹. Manually stripping fecal material from rainbow trout resulted in settleable solids with a median settling velocity of 0.7 cm s⁻¹. Examination of the settling velocity curves show that halving the overflow rate (OFR) from 2 to 1 cm s⁻¹ changes the removal efficiency from 0.61 to 0.73, an increase of about 20%. Halving the OFR again to 0.5 cm s⁻¹ increases the removal efficiency to 0.81, an improvement of about 11%. Settling characteristics of aquacultural solids will vary from facility to facility. The methods described in this paper can be used to perform a similar type of analysis at other aquacultural sites, which may be growing other species under different management regimes.     

Constructed wetlands as a treatment method for effluents from intensive trout farms

This study examined the effects of different hydraulic loading rates on the treatment efficiency of subsurface flow (SSF) constructed wetlands treating effluents from trout farming over a period of 6 months. Six identical wetland cells with a pre-sedimentation zone of 9.6 m² and a root zone of 23.6 m² were loaded with effluents from intensive trout farming (> 2.1 kg feeding stuff per L/s and day). The total runoff of 13.2 L/s was treated in the wetland cells, where two duplicate cells received equal hydraulic loads of 3.9, 1.8 and 0.9 L/s. All examined wetland cells had significant treatment effects on the nutrient fractions containing particulate matter [total nitrogen (TN), total phosphorous (TP), biological oxygen demand in 5 days (BOD₅), chemical oxygen demand (COD), and total suspended solids (TSS)].

Efficiency was between 5.5% for TN and 90.1% for TSS. The SSF wetland also had a high treatment effect on total ammonia nitrogen (TAN), with efficiencies of 61.2 to 87.8%. Nitrate nitrogen (NO₃–N) and phosphate phosphorous (PO₄–P) showed a significant increase in the wetland effluent by 8.4 to 209%. Nitrite nitrogen (NO₂–N), had no significant, or significant effluent increase depending on the inflow rate. Treatment efficiency for particulate nutrients and TAN increased with decreasing hydraulic load, while the differences between 1.8 and 0.9 L/s were not significant. The treatment efficiency for TP was constant for all cells, at around 40%. The wetland receiving 3.9 L/s was over-flooded after 10 to 12 weeks due to colmatation. Nevertheless, the wetland still showed high treatment efficiencies. For commercial trout farms, SSF wetlands are a highly effective method of effluent treatment. A hydraulic load of 1 L/s on 13.3 m² wetland area (1.8 L/s on the examined wetland) seems most suitable. Higher loads lead to accelerated wetland colmatation, while lower loads waste space.     

营养液膜技术栽培牧草净化循环流水水产养殖废水的试验

为研究植物生态净化技术集成至循环流水水产养殖系统的可行性,构建了4个(4重复)3.0m×0.5m×0.05m(长×宽×高)的植物滤器处理淡水白鲳(Colossoma brachypomum)高密度养殖废水。每个植物滤器生长0.8m2NFT(营养液膜技术)培多年生黑麦草(Lolium perenneL.)。废水每周更换一次,每次25.4L,连续运行40d。7d循环灌溉处理后,NO3--N、TN、TP、COD的去除率分别达96.1%、86.2%、90.5%、88.7%,pH从6.4升高至8.4,而水体积只消耗29.7%。除UIA由于pH升高而超标外,所有水质指标均符合渔业水质标准。牧草日增长仅2.3mm,显著低于用商品营养液培育的牧草生长速度(日增长13.2mm)。鲜草TAN和NO3--N含量分别为107.9和42.5μg.g-1,试验结束时收获鲜草582.9g.m-2,烘干后得到干草102.5g.m-2,干湿比0.176。结果表明,植物滤器能解决生物滤器引起的N、P、COD累积以及pH下降等问题,是一种环境友好的水处理方法。为使牧草良好生长,建议定期将牧草返回培育系统用商品营养液培养一段时间。     

Denitrifying bioreactor inflow manifold design for treatment of aquacultural wastewater

Recirculating aquaculture systems (RAS) facilities subject to point-source effluent regulations need to implement cost-effective N remediation for their wastewater outflows. Relatively low-cost denitrifying “woodchip” bioreactors can effectively remove N from aquaculture effluents for at least one year, but questions remain about bioreactor lifespan for aquacultural wastewaters. Four pilot-scale bioreactors (L × W × D; 3.8 × 0.76 × 0.76 m), two with a conventional single distribution inflow manifold and two with an experimental multiple-header, feed-forward distribution manifold, were operated over 784 d to observe second-year N removal performance and to determine if the manifold design can influence bioreactor effectiveness. The study also quantified performance metrics for chemical oxygen demand, total suspended solids, and phosphorus. Manifold style did not have notable impact on bioreactor performance when treating wastewater under the facilities’ normal operating conditions, but the multiple distribution style demonstrated an 11 % increase in nitrate and 12 % increase in total suspended solids removal efficiency over the single distribution manifold toward the end of the study when bioreactors treated higher strength wastewater. Additionally, bioreactor performance in both manifold designs decreased from an average of 92 % total suspended solids removal efficiency under normal operating conditions to <76 % when treating the high-strength wastewater. The bioreactors provided N removal rates of 17−25 g NO₃-N m⁻³ d⁻¹ during the second year of study, demonstrating woodchip bioreactors can effectively treat aquaculture effluent for at least two years without major detrimental impacts due to clogging.     

The use of clarifiers to remove and control the total suspended solids in large-scale ponds for production of Litopenaeus vannamei in a biofloc system

High concentrations of total suspended solids (TSS) need to be controlled, as they can affect shrimp production due to the excess of particles in the water column. Water renewal and clarification are alternatives used to reduce TSS. In order to determine the better method of TSS control, we carried out a study using water renewals and clarification on a commercial scale with nine ponds (600 m² each) in an intensive biofloc system. A total of 87 shrimp m⁻² were stocked in each unit divided into three treatments: R (water renewal), C1 (one clarifier) and C2 (two clarifiers in series). Each treatment had three replicates, and the experiment lasted 105 days. There were no significant differences (p > 0.05) in the parameters of water quality and zootechnical performance. Significant differences (p < 0.05) were observed in the performance of clarifiers (time of operation, TSS removal rate and total solids removed) and in the efficiency of water use and effluent generation. All treatments maintained controlled TSS levels, although C2 showed a better removal efficiency than C1, with percentages rates of 71.2 and 47.9%, respectively. This difference resulted in a 160-hour reduction in the total operating time in C2. Compared to the R treatment, the percentages of water saved in C1 and C2 were 50.7 and 51.3% higher, respectively, and the percentages of effluent generated in C1 and C2 were 97 and 96% lower, respectively. The use of clarifiers helps to control TSS concentrations in large-scale. In addition, they reduce both the amount of water used for renewals and the effluent discharges into the environment, thereby increasing biosafety in the biofloc system.     

Efficacy of a pilot-scale wastewater treatment plant upon a commercial aquaculture effluent: I. Solids and carbonaceous compounds

A pilot-scale wastewater treatment station was built and operated at a commercial recirculating aquaculture facility in order to initiate, characterize and optimize the operation of a treatment strategy for effluent recovery and reuse. The treatment train consisted of sedimentation, denitrification, ozonation, trickling filter treatment, and chemical flocculation. The study consisted of four different sets of treatment conditions, differentiated by alternative use of 6 or 4 lpm flow and recycling rates, ozone doses between 36.6 and 82.5 mg O₃/l water, and 6- or 9-min ozonation time. The effects of treatment on solids and dissolved organic compounds are reported here. Over 70% of solids were removed by sedimentation under all experimental conditions. At the end of treatment, up to 99% of TSS was removed due to the combined action of ozonation and chemical flocculation. COD removal was not significantly different among experimental conditions by sedimentation (59.2–62.7%, p > 0.05), but was positively correlated with ozone dose (slope = 0.452, r² = 0.99), yielding total COD removal η(CODt) of 19.8–40.7%. Of these amounts, 60.4–66.5% of COD was removed with foam, while the balance was mineralized. The ozone reactivity was 83.7% at a dose of 82.5 mg O₃/l water. The ozone consumption coefficient Y(O₃/CODox) for COD oxidized was 1.92–2.23 g/g O₃ COD and 0.70–0.78 g O₃/g COD when total COD removed was considered. Overall, 87.9–92.4% of COD was removed by the treatment train, to an average of 44 mg/l at the highest ozone dose, a value 3.3–3.9 times less than in fish tanks. Under the same conditions, cBOD₅ was reduced by 88%, 3.8–4.1 times less than in fish tanks. The water’s biodegradability was increased by over 20%. DOC did not change significantly through the treatment train, and fluctuated through the system due to methanol addition to support denitrification. Work with the pilot station showed that the treatment strategy employed could support effective recovery and recycling of aquaculture effluent, although salts and refractory organics may accumulate in the system.     

3种填料对集装箱循环水养殖废水处理的初步研究

为探讨聚丙烯塑料发泡材料(EPP)、悬浮球填料和海绵填料对集装箱循环水养殖废水中细菌吸附性能的差异,以及3种填料挂膜启动和挂膜成熟后对氨氮(NH_4~+-N)、亚硝酸盐氮(NO_2~--N)和硝酸盐氮(NO_3~--N)的净水效果,以集装箱循环水养殖废水为研究对象,采用自然挂膜的方式进行了为期3个月的试验,并对相关指标进行测定。结果显示:EPP填料对养殖废水中细菌的吸附能力最好,另外两种填料对细菌的吸附能力次之并且差异不显著(P0.05);3种填料自然挂膜成熟的时间分别为21 d、26 d和30 d;各填料挂膜成熟后处理高浓度NH_4~+-N养殖废水时,NH_4~+-N浓度与NO_2~--N浓度之间的关系可以用多项式y=ax~2+bx+c进行拟合,NH_4~+-N浓度与NO_3~--N浓度之间的关系可以用对数式y=aln(x)+b进行拟合。研究表明:EPP填料、悬浮球填料和海绵填料均可作为生物填料用于集装箱循环水养殖系统。     

共聚苯胺吸附剂对含汞废水的处理

利用静态吸附法,研究了化学氧化共聚改性的新型聚苯胺吸附剂对汞离子的去除性能。发现共聚苯胺对汞离子废水有着优异的吸附效果。处理初始浓度低于750mg·L-1的含汞废水,去除率在98.4%以上。20mg共聚苯胺处理初始浓度为1980mg·L-1的汞离子时,吸附容量可高达1113.6mg·g-1。处理初始浓度低达20mg·L-1的含汞废水时,可获得高达99.99%的去除率,处理后的废液达到了国家排放标准。     

In situ hypochlorous acid generation for the treatment of brackish shrimp aquaculture wastewater

This study presents an unconventional framework for treating shrimp aquaculture wastewater based on in situ hypochlorous acid (HOCl) oxidation. The in situ oxidation process makes use of the salinity present in aquaculture wastewater to generate HOCl. The undivided electrolytic cell consisted of two sets of graphite as the anode and stainless sheets as the cathode. The electrochemical oxidation of shrimp aquaculture wastewater was carried out for an influent COD concentration of 1730 mg L^?1 at current densities of 37.2 and 74.5 mA cm^?2. The results showed that in order to achieve a residual COD concentration of 50±5 mg L^?1 at current densities of 37.2 and 74.5 mA cm^?2, electrolysis periods of 60 and 30 min are required respectively. Hence, for the above‐mentioned current densities, the corresponding energy requirements were found to be 19.4 and 13.3 W h L^?1. The cost incurred in treating 1 m³ of shrimp aquaculture wastewater was found to be RM 4 and 3 when the electrolytic reactor was operated at a current density of 37.2 and 74.5 mA cm^?2 with a salinity of 23‰. The foregoing study highlights the potential of in situ HOCl oxidation in treating brackish shrimp aquaculture wastewater.     

一株淡水螺旋藻的盐度驯化及其净化养殖废水作用

为了研究螺旋藻吸收作为海水养殖废水净化手段的可能性,通过2种方法对一株淡水螺旋藻钝顶螺旋藻(Spirulina platensis)进行了海水环境的适应性驯化试验.结果表明,逐级提高海水比例法可以使得淡水螺旋藻较好地适应海水环境.还对驯化成功的螺旋藻进行了生长环境如pH、温度、光照度、COD等分析考查,得出最适宜的生长或操作条件.结果表明,螺旋藻使用的最佳条件为pH 6～11、温度25～40 ℃,最佳使用浓度为91×104 cell/mL左右,加入有机物能够促进螺旋藻的生长繁殖.驯化后的螺旋藻对于实际的养殖废水有较好的净化效果.     

Practical applications of low-pressure hydrocyclone (LPH) for feed waste and fecal solid removal in a recirculating aquaculture system

In this work, the practical application of a low-pressure hydrocyclone was examined for feed waste and fecal solid removal for common carp (27 ± 3.1 g, average ± SD) and Nile tilapia (33 ± 3.4 g, average ± SD) in a recirculating aquaculture system. The dimensions of the low-pressure hydrocyclone included an inflow diameter of 30 mm, a cylinder length of 575 mm, an overflow diameter of 60 mm, an underflow diameter of 50 mm, a cylinder diameter of 335 mm and a cone angle of 68°. The different operating conditions tested were inflow rates of 400, 600, 800 and 1000 ml s⁻¹, and underflow rates of 25%, 25%, 20% and 10% of the inflow rates, respectively. Feed waste totals of 4.1 to 4.8% and 3.6 to 4.0% of the feed intake were produced by the common carp and Nile tilapia, respectively. The maximum separation efficiency (Et) for the feed waste from the common carp was 71% at an inflow rate of 600 ml s⁻¹ with an underflow rate of 25% of the inflow rate. The maximum separation efficiency for the feed waste from the tilapia was 59% at an inflow rate of 400 ml s⁻¹ with an underflow rate of 25% of the inflow rate. The fecal solid production estimated from the digestibility was 37.9% and 35.7% of the feed intake for the common carp and Nile tilapia, respectively. The maximum separation efficiency for the feces from the common carp was 60% for an inflow rate of 600 ml s⁻¹ and an underflow rate of 25% of the inflow rate. The maximum separation efficiency for the tilapia feces was 63% at an inflow of 400 ml s⁻¹ with an underflow rate of 25% of the inflow rate. The low-pressure hydrocyclone can be adopted for prefiltration and/or post-filtration for the removal of various sized solids. Furthermore, the solids separated from the underflow can be easily removed for further processing.     

不同浸没模式下两种滤料对水产养殖废水处理效果研究

将生物陶环和珊瑚石两种滤料分别采用半浸没式和全浸没式实验处理养殖废水。结果显示,在2种过滤模式下,生物陶环、珊瑚石生物滤料的生物膜成熟时间分别为8 d和10 d。经过20 d的处理,4个实验组NH4＋-N, NO2--N, COD的浓度均显著低于对照组,相比于对照组NH4＋-N浓度降低51％以上, COD降低40％以上;半浸没过滤模式的实验组对NH4-N、 NO2--N的去除率均显著高于全浸没实验组;全浸没实验组对COD的去除率显著高于半浸没实验组。半浸没式过滤生物陶环实验组表面AOB数量最高,达4.68×102 cfu/g,全浸没实验组HB数量均显著高于半浸没实验组。结果表明所用4种处理方式处理养殖废水均有较好效果。     

碳源及C/N对反硝化细菌净化循环养殖废水的影响

针对目前循环养殖废水水质处理过程中存在脱氮碳源不足的问题,本文以高NO3--N降解能力和低NO2--N积累量为碳源优化指标,研究了乙醇、丙三醇、葡萄糖、蔗糖、乙酸钠和酒石酸钾钠6种碳源及不同碳氮比（C/N）对复合菌群净化循环养殖废水效果的影响。试验结果显示,不同碳源及C/N对养殖废水的NH4 -N去除率并无显著差异,且各处理组的NH4 -N去除率高达98%左右,显著地高于对照组（p<0.05）;当以葡萄糖、蔗糖等糖类物质为外加碳源时,试验过程中有明显的NO2--N积累现象;当以醇类物质为外加碳源时,NO2--N积累量几乎为零,且NO3--N去除率高达90%左右,显著地高于对照组（58.96%）;特别是以乙醇为外加碳源且C/N为3.0时,复合菌群对养殖废水的TN、NH4 -N和NO3--N去除率分别高达93.28%、98.90%和91.82%。虽然外加碳源短期内会引起水体CODMn含量大幅升高,但可被反硝化细菌迅速降解;此外,外加碳源还能改善水体pH值,经处理组净化后的水体pH值维持在7.5左右。试验结果表明,循环养殖废水水质净化过程中添加相应的碳源及并适当控制C/N比能显著改善池水水质,提高生物脱氮效率。     

人工湿地联合塘内设施调控生产性虾塘水环境的效果与技术

研究了由表面流与水平潜流组成的复合人工湿地联合使用塘内曝气增氧机与人工净化网调控生产性淡水对虾养殖塘水环境的效果与技术。养殖中后期(约60 d后), 湿地以1.65 m/d水力负荷, 3次循环处理虾塘废水, 有效调控虾塘水质, 确保养殖成功。结果表明湿地对废水中有害物质均可程度不等地去除, 蓝绿藻得以控制, 出口水 -N与BOD5分别为极显著(P<0.01)与显著(P<0.05)去除, 去除率与去除速率分别为72.6%, 0.467 g/(m²·d)与29.7%, 2.651 g/(m²·d), -P为41.7%, 0.022 g/(m²·d), TN为26.1%, 2.619 g / (m2?d), CODMn为15.9%, 3.738 g/(m²·d), -N去除率仅3.6%, 但去除速率较高[0.462 g/(m²·d)]。湿地静止4 d期间, 废水中 -N与 -N去除率达96.8%与93.3%, 均极显著去除(P<0.01)。养殖周期试验塘水化学指标均维持在虾安全生长范围内, 收获虾8.81 g, 9.36 cm; 对照塘因爆发蓝绿藻仅养殖60 d, 收获虾3.06 g, 6.54 cm。试验表明, 在不用药、不换水条件下, 联合塘内设施, 人工湿地以较高水力负荷与低频率运转可有效调控虾塘水质, 确保养殖成功。     

适于稻作的水处理系统构建及运行效果

为了处理和资源化利用池塘养殖废水,结合生物滤池和水上稻作技术,设计并构建了一种适合于水稻种植的水处理系统。系统运行试验结果表明:在水力负荷为0.29~0.58 m/d,气水比为2~4时都可以获得比较好的水处理效果。将池塘养殖有机结合形成的循环水养殖系统中,在水力负荷为0.58 m/d,气水比为2的条件下,系统对养殖废水中TAN、TN、TP和CODMn的去除率分别为33.75%~34.31%、59.21%~64.53%、68.43%~73.75%和71.66%~74.37%。与此同时,水处理系统获得7 127.01 kg/hm~2的水稻产量。由此实现养殖废水资源化利用,是一种可持续的水产养殖方式,可为我国渔农混作区池塘养殖废水的处理和循环利用提供一种新方法。     

短时间微流水处理对池塘养殖草鱼鱼肉品质的提升作用

以池塘养殖草鱼为对象,采用室内微流水系统处理草鱼,研究处理时间(0、1、4、7和10 d)对草鱼鱼肉基本营养组成、滋味特征和滋味成分、气味特征和气味成分、感官评分的影响,以评价短时间微流水处理对草鱼鱼肉品质的提升作用。结果显示,微流水处理对草鱼鱼肉的基本营养成分、滋味成分、气味成分和感官评分均有显著影响。随着微流水处理时间延长,草鱼鱼肉中脂肪和总糖含量显著下降、灰分含量显著增加,但鱼肉中蛋白质含量无明显差异。滋味分析仪(电子舌)和气味分析仪(电子鼻)检测结果表明,微流水处理能显著改变草鱼鱼肉的滋味特征和气味特征。处理后的草鱼鱼肉中IMP、鲜味氨基酸(天冬氨酸和谷氨酸)、甜味氨基酸(丝氨酸和丙氨酸)、苦味氨基酸(亮氨酸和异亮氨酸)含量显著增加,而其总挥发性盐基氮(TVB-N)、二十二碳六烯酸(DHA)等含量显著减少。微流水处理4 d的草鱼鱼肉气味评分、滋味评分和色泽评分显著高于处理0和1 d的草鱼样品,而与处理7和10 d的草鱼样品无差异。研究表明,短时间微流水处理能有效提升草鱼鱼肉品质,适宜处理时间为4 d,处理后的草鱼鱼肉腥味明显减弱、鲜味明显增强。     

冷水鱼循环水养殖中的低温氨氮处理技术研究

为解决冷水鱼养殖过程中养殖水体中的氨氮累积问题,根据低温生物滤器及臭氧催化氧化处理氨氮的特点,设计了冷水鱼工厂化养殖氨氮处理系统并进行了试验。试验基于以臭氧氧化为主、低温生物处理为辅的处理工艺,试验鱼为虹鳟鱼,养殖密度为23 kg/m3,试验水体约为10 m3,试验周期为7 d。结果表明,该系统能够满足冷水鱼工厂化养殖过程中有关氨氮处理的水质指标要求,处理后的养殖池进水口的水质指标总氨氮≤0．18 mg/L,硝酸盐氮氮≤29．43 mg/L,亚硝酸盐氮氮≤0．1 mg/L;养殖水体氨氮浓度监测表明,臭氧在水中残留低于0．008 mg/L,符合养殖鱼类对水体臭氧浓度的安全要求。