Adapting to life in a changing climate: optimizing water treatment processes

许多饮用水处理厂（WTPs）现在使用膜去除有害微生物。气候变化预计会增加wtp的藻类和蓝藻相关问题，包括更大的味道和气味事件，更大的膜污染和蓝藻毒素的释放。溶气浮法（DAF）是一种去除藻类和蓝藻的有效方法，但仅在部分wtp中使用。活性炭吸附过程是去除味道和气味化合物、蓝藻毒素和其他微量污染物的最佳技术之一；由于在热再生过程中有5 - 15%的交流质量损失，目前正在开发替代吸附剂，如NYEX。本提案的目标是通过以下举措帮助改善wtp，使其更能适应气候变化。首先，开发一种新的试验台规模的DAF测试装置，并在不同的水域进行测试，包括在藻华期间进行测试。其次，比较DAF和压舱沉降的效率，压舱沉降是一种竞争性的分离过程，用于处理藻华期间的水。申请人团队发现，对于渥太华河的水，DAF预处理对减少膜污染的效果优于沉淀法预处理。第三，确认这种DAF优势是否受到膜系统类型和处理水类型的影响。计划中的实验包括藻华条件下的测试。四是继续研究NYEX吸附/电化学再生系统替代活性炭吸附去除痕量污染物。具体来说，申请人的团队将确定NYEX去除微量污染物（如杀虫剂和蓝藻毒素）的能力是否比活性炭受天然有机物存在的影响更小，这是活性炭的缺点。所有这些举措将有助于设计水处理系统，使其在未来更频繁的藻类/蓝藻繁殖中表现更好，并避免2014年8月俄亥俄州托莱多3天“禁止饮用令”的情况。

Many drinking water treatment plants (WTPs) now use membranes to remove harmful microorganisms. Climate change is expected to increase algal and cyanobacterial-related problems at WTPs including greater taste and odour incidents, greater fouling of membranes and the release of cyanobacterial toxins. Dissolved air floatation (DAF) is an effective process for the removal of algae and cyanobacteria, but it used in only some WTPs. Activated carbon adsorption processes are one of the best technologies for the removal of taste and odour compounds, cyanobacterial toxins and other trace contaminants; due to the 5 to 15% AC mass losses during thermal regeneration, alternative adsorbents, such as NYEX, are currently being developed. The objective of this proposal is to help improve WTPs and make them more climate-change resilient through the following initiatives. First, to develop a new bench-scale DAF testing unit, and test it for different waters, including one during an algal bloom. Second, to compare the efficiency of DAF with that of ballasted sedimentation, a competing separation process, for the treatment of water during algal blooms. The applicant's team has found that for Ottawa River water, to reduce membrane fouling pretreatment by DAF was superior to pretreatment by sedimentation. Third, to confirm if this DAF superiority is impacted by the membrane system type and the type of water treated. Planned experiments include testing during algal bloom conditions. Fourth, to continue researching the NYEX adsorption/electrochemical regeneration system as an alternative to activated carbon adsorption for the removal of trace contaminants. Specifically, the applicant's team will determine if NYEX's capacity to remove trace contaminants (such as pesticides and cyanobacterial toxins) is less impacted than that of activated carbon by the presence of natural organic matter, which is a drawback of activated carbon. All of these initiatives will help design water treatment systems that can perform better under the more frequent algal/cyanobacterial blooms expected in the future, and avoid situations like the 3-day “no drink order` in Toledo, OH in August 2014.