Novel Effluent Desalination Processes: Sustainable Water Recovery and Energy Generation in Mining Sites

拟议的研究计划旨在减少采矿和金属行业的环境足迹，特别是与水使用相关的程度。我们的目标是开发创新的、整体的、可扩展的、节能和环保的污水淡化工艺。目标是：(I)通过以低成本从工艺溶液、污水和尾矿池回收水来减少受污染的含水废物量；(Ii)提高剩余盐水中有价值的金属含量(如果有的话)，从而使其后处理在经济上可行；以及(Iii)利用尾矿池中受控的污水混合来产生可再生能源。 拟议的研究计划将对HQP进行创新工艺培训，以从污水和尾矿池中回收水和能源。我们假设，这些新工艺将同时提高污水的水回收产量，并降低该部门的能源消耗。我们打算主要专注于在零度以下运行的技术，以利用加拿大寒冷的冬季气候，并以纯冰的形式回收水。不仅冷冻的能量比蒸发的能量少7倍，而且在加拿大冬天每年有几个月是免费的。我们建议研究的流程是冷冻浓缩(FC)和天然气水合物淡化(HyDesal)。我们工作的新颖性是基于使用冷的超细气泡(即微米和纳米气泡的混合物)。在受控条件下，气泡将作为结冰的核心，以纯微小冰晶的形式回收水，而不允许杂质进入冰基质。此外，我们打算简化流出流和尾矿的处理，以便通过正向渗透(FO)将这些多组分含水溪流的水通过正向渗透(FO)输送到对环境无害的单组分DRAW溶液中，以回收水。FO不需要外部能量输入；相反，它是由流出物和更浓缩的提取液之间的渗透压差驱动的。FC将用于从所产生的稀释的抽取液中回收清洁的水，这需要能量。最后，我们打算开发一种膜过程，盐度梯度功率，通过在尾矿库中受控混合，回收排入尾矿库的流出物的混合释放能量，类似于从植物中回收废热的方式。 这项研究计划有助于保护人们获得清洁水的权利，并在气候变化导致环境立法障碍变得更加严格的时代提高加拿大矿业和金属行业的竞争力。它还产生了与加拿大和国际组织和行业合作的强大潜力，旨在将加拿大定位为世界上在零液体排放研究、法规和应用方面的领先国家。

The proposed research program aims to reduce the environmental footprint of the mining and metals industry, especially to the extent related to water usage. We aim to develop innovative holistic scalable energy efficient and environmentally friendly effluent desalination processes. The objectives are: (i) to reduce the contaminated aqueous waste volume by recovering water from process solutions, effluents, and tailings ponds at low cost, (ii) to upgrade the valuable metal content (if any) in the remaining brine, thus making its re-processing economically viable, and (iii) to utilize the controlled mixing of effluents in the tailings ponds to generate renewable energy. The proposed research program will train HQP in innovative processes to recover water and energy from effluents and tailings ponds. We hypothesize that these novel processes will simultaneously increase the water recovery yield from effluents and lower the energy footprint of the sector. We intend to primarily focus on technologies that operate at sub-zero temperatures to take advantage of the Canadian cold winter climate and recover water in the form of pure ice. Not only is the energy for freezing 7 times less than that of evaporation, but also it is free several months per year in Canada during winter. The processes we propose to work on are freeze concentration (FC) and gas hydrate desalination (HyDesal). The novelty of our work is based on the use of cold ultra fine gas bubbles (i.e., mixture of micro- and nano-bubbles). Under controlled conditions, the bubbles will serve as nuclei for ice formation, resulting in the recovery of water in the form of pure tiny ice crystals, without allowing impurities to enter into the ice matrix. Also, we intend to simplify the treatment of effluent streams and tailings for water recovery upon passing the water from these multi-component aqueous streams into environmentally benign single-component draw solutions via forward osmosis (FO). FO requires no external energy input; instead, it is driven by the osmotic pressure difference between the effluents and more concentrated draw solutions. FC will be used to recover clean water from the resulting diluted draw solution, which requires energy. Finally, we intend to develop a membrane process, salinity gradient power, to recover the released energy of mixing of the effluents discharged into the tailings ponds through their controlled mixing in the latter, similar to how waste heat is recovered from plants. This research program contributes to the protection of people's right to clean water and advances the competitiveness of the Canadian mining and metals industry in an era that environmental legislation barriers become stricter due to climate change. It also generates a strong potential for collaboration with Canadian and international organizations and industries and aims to position Canada as the world's prominent country in zero liquid discharge research, regulations, and applications.