海水淡化反渗透膜微生物污染及防控研究进展

随着反渗透技术在海水淡化及废水处理等方面的应用推广,反渗透膜污染问题显得越来越突出,尤其是不可逆的微生物污染,现已成为一个世界性难题.本文基于反渗透膜微生物污染的研究现状及进展,总结归纳微生物污染过程中三个关键阶段包括微生物粘附、生长和扩散的形成特点,发生机制及其影响因素;全面论述微生物污染膜的表面评价方法及膜性能评价方法如水利参数评价等的优缺点;针对微生物污染膜形成的不同生长阶段分别提出相应的防控策略如预处理、水利运行参数调控、反渗透膜的改性及清洗等;最后提出分离膜微生物污染研究的发展方向.     

主流海水淡化技术及未来发展趋势

介绍目前海水淡化的三项主流技术及其特点,比较各项技术的优劣势,并简要分析和预测海水淡化技术的未来发展情况。     

改进型多级闪蒸海水淡化系统的经济性分析

结合多级闪蒸海水淡化技术(MSF)和低温多效蒸馏海水淡化技术(LT-MED)的优点,提出了一种改进型多级闪蒸海水淡化系统(MSF-E),并从理论上研究了MSF-E系统的造水比、年平均淡化水成本等经济性指标.研究结果表明,与现有MSF装置相比,在引出质量份额从0增加到理论最大值0.743时,造水比可提高42.6%,同时年平均淡化水成本可下降41.3%,证明MSF-E系统有较大的实用价值和应用前景.     

低温多效蒸发海水淡化装置的计算分析

建立了多效蒸发海水淡化装置计算模型,对串流、并流和并叉流三种不同工艺流程下的低温多效蒸发海水淡化系统进行了计算和分析。计算结果显示,对于给定的多效蒸发海水淡化装置,提高加热蒸汽温度,可大大提高装置的淡化水量,同时对加热蒸汽的需求量也增大,但造水比随加热蒸汽温度的升高呈减小趋势;就三种工艺流程而言,并叉流具有较好的热利用率。     

横管降膜蒸发太阳能海水淡化装置的性能分析

在分析横管降膜蒸发机理的基础上，设计了一台降膜蒸发太阳能海水淡化装置，并对影响该装置性能的因素进行了实验研究。结果表明，该装置比传统的叠盘式太阳能海水淡化装置瞬态时间短，蒸发效果好，运行温度低。保持合理的海水喷淋密度，使海水在管外降膜蒸发，可使装置在较宽的温度范围内(70～9012)运行，且具有较高的淡水产量和能源利用率(7096以上)。     

Potential for economic solar desalination in the Middle East

Fresh water forms only about 1% of the total water available on earth. Technologies for the desalination of seawater have considerably matured in the last decade. However, the energy required for the desalination is usually expensive in arid areas where fresh water is required. Renewable energy provides a clean, free, and low-maintenance source of energy for desalination, limited only by their initial cost, and the variability of the available energy. In this paper the potential use of solar energy for the desalination of seawater in the Middle East is evaluated. Multi-Stage Flash (MSF) desalination requires large amounts of energy, while Reverse Osmosis (RO) desalination is more energy efficient. Solar distillation is a very simple and direct method that may be used, requiring only large flat areas of land, having no running energy costs and being very suitable for remote areas. Photovoltaics is another promising renewable energy source for seawater desalination in the Middle East. It is best suited for the RO and Electrodialysis (ED) methods. The desalination plant doesn't need to run continuously, and therefore no storage batteries are required. Diesel and / or natural gas may be used as a backup energy.     

环渤海地区膜法海水淡化预处理工艺探讨

海水淡化是环渤海地区经济发展的重大课题.海水预处理是淡化的关键过程.文章结合渤海湾地区海水水质的特点,讨论了膜法海水淡化预处理工艺的选择,设计时对水温,浊度变化的考虑.对连续膜过滤工艺的类型和特点作了介绍.     

吸收式热泵多效蒸发海水淡化热力性能研究

提出了两级吸收式热泵多效蒸发海水淡化工艺流程,并建立了系统的数学模型。计算分析了溴化锂溶液浓度和加热蒸汽温度对系统的造水比、生产单位淡水所需传热面积和吸收式热泵的热力系数的影响。研究结果表明,系统的造水比和吸收式热泵的热力系数随加热蒸汽温度和LiBr浓溶液浓度的降低而增大,生产单位质量淡水所需传热面积随加热蒸汽温度的降低而急剧增加;通过调整溴化锂溶液的浓度,能够实现对不同品质热源的利用;该系统不仅能够保证淡水不被溴化锂污染,而且其造水比明显优于喷射泵多效蒸发系统和多效蒸发系统。     

Seawater quality and microbial communities at a desalination plant marine outfall. A field study at the Israeli Mediterranean coast

Global desalination quadrupled in the last 15 years and the relative importance of seawater desalination by reverse osmosis (SWRO) increased as well. While the technological aspects of SWRO plants are extensively described, studies on the environmental impact of brine discharge are lacking, in particular in situ marine environmental studies. The Ashqelon SWRO plant (333,000 m³ d⁻¹ freshwater) discharges brine and backwash of the pre-treatment filters (containing ferric hydroxide coagulant) at the seashore, next to the cooling waters of a power plant. At the time of this study brine and cooling waters were discharged continuously and the backwash discharge was pulsed, with a frequency dependent on water quality at the intake. The effects of the discharges on water quality and neritic microbial community were identified, quantified and attributed to the different discharges. The mixed brine-cooling waters discharge increased salinity and temperature at the outfall, were positively buoyant, and dispersed at the surface up to 1340 m south of the outfall. Nutrient concentrations were higher at the outfall while phytoplankton densities were lower. Chlorophyll-a and picophytoplankton cell numbers were negatively correlated with salinity, but more significantly with temperature probably as a result of thermal pollution. The discharge of the pulsed backwash increased turbidity, suspended particulate matter and particulate iron and decreased phytoplankton growth efficiency at the outfall, effects that declined with distance from the outfall. The discharges clearly reduced primary production but we could not attribute the effect to a specific component of the discharge. Bacterial production was also affected but differently in the three surveys. The combined and possible synergistic effects of SWRO desalination along the Israeli shoreline should be taken into account when the three existing plants and additional ones are expected to produce 2 Mm³ d⁻¹ freshwater by 2020.     

大型低温多效海水淡化装备技术特点分析

对大型低温多效海水淡化装备设计过程中遇到的几点问题,包括工艺流程选择、设备结构优化、制造材料选择等进行分析,并提出具体建议。