海水淡化工程浓盐水排海扩散器方案研究

本文以渤海湾为例,运用MIKE3 FM数值模拟软件,建立了天津港附近海域浓盐水排海三维盐度扩散模型,模拟了无扩散器、有扩散器（一字型、Y型、T型）,以及不同端口间距和出口流速扩散器条件下浓盐水排海后盐升扩散分布情况。研究结果表明：扩散器能够显著增强浓盐水扩散稀释效果,对于研究海域3种形状扩散器扩散稀释效果相近;适宜的端口间距和出口流速设计将提升扩散器的扩散稀释效果。相关研究结论可为科学优化海水淡化浓盐水排海方式,推动海水淡化与海洋环境和谐可持续发展提供技术支撑。     

晋江海域海水淡化排海盐度场三维数值模拟

本文运用MIKE3数值模拟软件,建立了晋江海域海水淡化排海三维温、盐扩散模型,模拟了不同潮期、潮时盐度的水平和垂直方向扩散情况。结果表明,浓海水排海后盐度分布受水位和流速的影响,水位越高、流速越大,稀释和扩散作用越明显,在垂向上的扩散距离越小。规模20万t/d海水淡化工程浓海水排放对附近海域盐升的水平影响在几百米范围内,垂向影响在3 m以内,且随着水位和流速的增加在水平和垂向上能够较快稀释扩散,在附近不存在环境敏感区的情况下,不会对海洋环境造成显著影响。     

海水淡化浓海水与电厂温排水混排方案研究

本文以渤海湾为例，运用MIKE3 FM数值模拟软件建立了渤海湾天津附近海域海水淡化浓海水与电厂温排水混合排放温盐扩散三维数值模型，开展了浓海水和温排水不同混合比例温盐扩散对比研究。研究结果表明：浓海水与温排水混合排放可以使受纳海域盐升范围显著减小，并且混合比例越高，效果越明显。在温升影响方面，与等量温排水单独排放相比，混合排放会使底层海域温升包络面积增大，表层减小，但当混合比例超过1：30（温排水量约为35 m³/s），表层和底层海域温升包络面积接近于等量温排水单独排放的温升包络面积；综合考虑温盐扩散，当海水淡化浓海水排放量在10×104 m³/d，盐升不超过20时，与温排水混合排放比例超过1：30（温排水量超过35 m³/s），盐度在排放口附近可稀释到背景值，由于混合排放密度变化引起的温度下沉影响几乎可以忽略不计。相关研究结论可为海水淡化浓海水科学排放/推动海水淡化和海洋环境和谐可持续发展提供技术支撑。     

高浓热盐水在胶州湾潮流作用下的输移扩散规律研究

水电联产已经成为目前大型海水淡化工程的主要建设模式,然而海水淡化过程产生的高浓热盐水直接排海对受纳水体的污染是1个有待解决的重要问题.为建立一个能够较准确地模拟高浓热盐水排入海洋中的输移扩散情况的三维数学模型,用来预测高浓热盐水进入海洋水体后经湍动混合与输移扩散后的时空分布特性,揭示高浓热盐水在潮流作用下的运动及演变规律,进而对排放影响作出分析判断.采用文中建立的数学模型对胶州湾西岸的某电厂高浓热盐水表面排海问题进行数值模拟,研究表明该模型较好地模拟和复演了胶州湾的潮流场和高浓热盐水输移扩散情况,规则半日潮流对浓盐水的输移扩散起着决定性作用,通过比较不同排放口底层温度升高和盐度升高等值线包络面积得出较合理的排放口选址.该模型为合理布置水电联产设备的取水口和排放口位置提供了有效途径,为沿海水电联产产物浓盐水排放后对近海水域的环境污染控制具有一定的实际意义和理论价值.     

基于MIKE21的渤海湾海水淡化浓盐水排海盐度场分布研究

运用MIKE21模型搭建计算网格,选取合适的计算参数,对渤海湾典型潮期、不同规模和位置海水淡化工程浓盐水排海后的盐度场分布进行了初步的模拟研究,计算了盐度升高面积。结果表明,合理选择海水淡化工程浓盐水排放口位置和排放时期,可以避免和减少浓盐水排放对海洋环境的影响。     

海水淡化排海浓盐水对胶州湾盐度分布影响

为考察海水淡化产生的浓盐水对胶州湾盐度分布的影响,利用POM模式,建立了胶州湾盐度扩散模型,分别以现有海水淡化量和2010年规划海水淡化量所排放的浓盐水量为输入条件,模拟计算了胶州湾盐度的分布和变化。模拟显示,2010年2月、5月、8月和10月胶州湾整个湾内平均盐度分别为30.9895,30.8040,30.0221和30.2306,较2008年分别增加约0.0276,0.0274,0.0212和0.0205。浓盐水排放位置附近局部海域盐度增加明显,如黄岛浓盐水排放点附近海域,2月大潮涨潮时盐度超过31.55的水域面积较2008年增加0.24 km2,并且出现0.08 km2盐度超过32.00的水域;2月大潮落潮时盐度超过31.55水域面积比2008年增加0.53 km2左右,盐度超过32.00的面积增加约0.16 km2。2月、5月、8月和10月最高值分别达到40.23,36.66,37.94和37.87。结合前期室内实验结果可以看出,2月份的盐度最高值超过对胶州湾浮游植物生长有明显影响的非检测浓度(38.62)。这表明,按2010年规划的海水淡化规模所产生的排海浓盐水尽管对整个胶州湾的盐度分布影响不大,但会导致局部海域盐度明显增加,从而可能会对该海域浮游植物生长造成一定影响。     

群岛峡道浓盐水排放扩散的三维数值模拟

采用三维潮流温盐数学模型对六横岛附近海域的水动力环境及盐度场分布进行数值模拟,并以实测资料进行验证,所建立模型可以较好地反映该海域潮流动力特征及盐度场的分布情况。利用验证后的三维数学模型,对海水淡化工程浓盐水排放后盐度场分布进行计算,将排放后的盐度分布与工程前进行对比分析,并推算盐升面积及垂向盐度增量。结果表明,海水淡化工程排放的浓盐水对六横岛海域盐度分布的影响主要集中在排水口附近的底层,影响区域呈带状分布,最大盐度增量为1.2左右,且排水口附近海域出现盐度垂向分层。     

围海造陆条件下排海高温浓盐水对渤海湾温盐场分布影响模拟及预测

自2000年以来围绕渤海湾的围海工程剧增,致使工程区附近潮流场发生变化,进而影响排海高温浓盐水的时空分布特征。本文通过建立2000年和2015年两种不同岸线、地形条件下的三维数学模型对渤海湾沿岸3个电厂高温浓盐水表层排海问题进行模拟,研究结果表明,渤海湾的潮流场和高温浓盐水输移扩散特征在近十几年发生了较大变化:工程后,渤海湾平均盐度增大0.203,平均温度升高了0.105℃,同时曹妃甸附近海域浓盐水输移扩散速度明显增加。增大排放口流量至12.7 m3/s,湾内最高温度为26.46℃,较2015年最高温度增加了2.72℃。本文模型可准确模拟及预测排海废水盐度、温度分布特征,为合理布置水电联产设备排放口的位置提供理论基础。     

南通污水排海工程排放点比选的数值模拟

采用数值模拟的方法,计算和分析了南通污水排海工程排放点位于-4m、-7m和-9m三个水深位置的污染物扩散影响,结果表明,在海域水动力条件下,-4m点高质量浓度COD水体面积最大,排放口污染最重,又位于浅海区,对海洋养殖极为不利,不宜选择;-7m点排放口和-9m点排放口均没有出现超过三类水质标准的区域,-7m点排放口影响水域COD质量浓度大部分为二类水质标准区域,只有面积很小甚至可以忽略不计的小范围三类水质标准区域,满足排海要求;-9m点排放口虽然对海域影响最小,但因其离岸距离过远,将大幅增加工程的施工及运营难度,为此,在能够保障COD排海条件的情况下,同时结合各方案管线长度带来的施工难度以及造价费用,采取-7m点为最佳排海口方案。     

海洋环境容量分析在规划环境影响评价中的应用

海洋环境容量是沿海城市区域发展的重要约束条件之一,根据规划环境影响评价的特点,在计算近岸海域汇流区域内污染物排放总量的基础上,预测规划年污染物排海总量,从而制定陆源污染物排海总量控制措施和目标,优化调整规划方案,海洋环境容量的大小与海域特征和海水水质目标有关。文章以大连湾为例,在潮流场数值模拟的基础上,计算了大连湾受纳水体水质对排放源的响应关系,结合混合区的确定,计算了主要污染物ＣＯＤ、无机氮和活性磷酸盐的最大允许排放量,为各个排污口排放的不同污染物制定相应的排放与削减量提供依据。     

Impacts of seawater desalination on the giant Australian cuttlefish Sepia apama in the upper Spencer Gulf, South Australia

With seawater desalination expanding rapidly, it is important that ecological studies are undertaken to determine the effects of brine discharge on the marine species in the area. The abundance of giant Australian cuttlefish (Sepia apama, Gray 1849) eggs and environmental data were recorded at nine sites near Point Lowly, Spencer Gulf, South Australia, an area where the largest desalination plant in the Southern hemisphere is proposed. In addition, the effects of different concentrations of desalination brine on the growth, survival and condition of cuttlefish embryos were investigated. The primary egg-laying sites for the cuttlefish were in the vicinity of Stony Point (sites 4 and 3) and the area with the least egg abundance was on the eastern and western areas around Point Lowly (sites 9 and 7) where no eggs were found. The survival of embryos decreased with an increase in salinity, with no embryos surviving to full term in salinities greater than 50‰. Mean weight and mantle length also decreased with increasing salinity. Besides elevated salinity, the brine also had increased concentrations of Ba, Ca, K, Sr and Mg relative to water near Point Lowly. Brine discharge from seawater desalination poses a potential threat to the unique spawning aggregation of the giant Australian cuttlefish, in the upper Spencer Gulf, South Australia.     

Management priorities for seawater desalination plants in a marine protected area: A multi-criteria analysis

The development of seawater desalination plants to increase water reliability in coastal areas poses a threat to the health of near shore marine ecosystems and may affect the effectiveness of marine protected areas (MPAs) that have been established to meet international conservation targets. This paper applies a multi-criteria analysis approach to quantify stakeholder groups’ priorities for seawater desalination plants that have been proposed in communities adjacent to a National Marine Sanctuary. All groups placed the highest importance on minimizing environmental impacts on protected areas and endangered species that could be affected by water intake and brine discharge emphasizing the need for integrated land and sea conservation. Minimizing socio-economic impacts on coastal communities was much less important. Stakeholders also weighted reducing pressure on water levels in rivers, streams, and aquifers as more important than increasing water for residential consumption, which may foster coastal growth rather than replacing water taken from other sources. The study further revealed differences in the importance of multiple management objectives among stakeholder groups, which highlights the need to elicit distinct priorities of all groups to understand concerns and potential conflicts of desalination with existing marine users. The analysis of consistency ratios revealed that around half of all surveyed stakeholders had high inconsistencies in their responses, which suggests either a lack of understanding of desalination, or reflects the complexity of establishing desalination plants in coastal areas adjacent to a marine protected area.     

Experimental biological effects assessment associated with on-shore brine discharge from the creation of gas storage caverns

Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC₅₀ values for the brine solute with salinity in the range of 40.9–43.5, whereas the EC₅₀ values for the concentrated seawater were in the range of salinity 44.2–49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine.     

天津南港工业区海水淡化工程附近海域水质调查

海水淡化工程带给城市经济社会效益的同时,也给海洋环境带来负担。海水淡化工程产生的大量排海浓海水在温度、盐度、有机物和营养盐、重金属、酸度、余氯、溶解氧和机械卷载效应等方面对海洋生态环境和海洋生物会产生一定影响,甚至对人类健康产生间接的危害。文章在2018年调查天津南港工业区海水淡化工程附近海域水质状况的基础上,分析海水水质变化趋势。研究表明：2018年调查区域主要污染因子为无机氮,其次为化学需氧量;其局部海域范围内无机氮和化学需氧量的含量各自呈现规律性变化;其他指标均未出现明显波动;南港工业区海水淡化工程附近海域的调查指标未发生明显变化。     

渤海湾海岸带开发对近海水环境影响分析

应用水动力学、水质数学模型,以渤海湾海岸带的几种典型开发活动--围海造地、海水淡化和河口建闸为例,模拟分析海岸带开发活动对渤海湾近岸海域水环境的影响.研究沿海围垦造成的潮通量、近岸流场水动力条件和污染物输移的变化;分析海水淡化工程浓缩海水的排放,高盐度高浓缩污染物对局部生态环境的影响;分析河口建闸后蓄积的污水排放方式对河口及近岸海域造成的影响,大量污水一次性排放会增大河口及近岸海域污染面积和污染程度.     

渤海地区晚第四纪环境演化与第四纪滨海相地下卤水的形成

由于气候变化和新构造运动,渤海曾发生多次海陆演化,从而形成了第四纪地下卤水。间冰期的海侵提供了形成地下卤水的水源,气候波动产生了海水浓缩的条件,而冰期海退过程中,陆源物质覆盖于海相沉积上,保存了地下卤水。对环境演化在“潮滩生卤”和“冰冻生卤”过程中重要作用的分析结果表明,在第四纪环境演变的过程中,两种生卤作用在地质时期卤水矿床形成中均具有重要意义,并且只要存在海水物源,就有可能形成地下卤水。