Progressive freeze concentration for wastewater treatment: dissolved solids removal and waste volume reduction

废水处理的渐进式冷冻浓缩：去除溶解固体并减少废物体积

• 批准号: 249575-2008
• 负责人: Gao, Wa
• 金额: $ 1.46万
• 依托单位: Lakehead University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=394376
• 关键词: Progressive; freeze; concentration; wastewater; treatment

Most contaminants in secondary industrial effluents (for example, effluents from petroleum refineries and pulp and paper mills) and membrane concentrate (which includes the contaminants blocked by the membranes, cleaning solutions and backwash water) from reverse osmosis and nanofiltration plants are in the dissolved form, some also contain toxic compounds. Currently, most membrane plants directly discharge the concentrate into surface water or sanitary sewers. Advanced treatment with multiple stage pretreatment processes is required to remove dissolved solids and evaporation or incineration is often the only choice for some wastewater residue/sludge volume reduction and disposal. High operating and capital cost and complex operations associated with these advanced treatment options limit their practical applications. Freeze concentration, due to its unique ability to remove dissolved impurities, reduce waste volume without addition of any chemicals and pretreatment, also recover a pure water stream, has great application potentials in these areas. Unlike the conventional suspension crystallization method, progressive freeze concentration (PFC) requires simplified operating system for separation of ice crystals from the feed water, thus can substantially reduce the process cost. However, no systematic investigation has yet been carried out on the mechanism of concentration efficiency in PFC and little information is available for engineering design of PFC processes for wastewater treatment. Laboratory experiments will be undertaken through this research program to: (1) investigate the freezing characteristics of selected wastewaters and membrane concentrate and their influence on PFC, (2) determine the impurity removal efficiency, toxicity reduction, and the capacity of volume reduction by PFC, (3) examine the effect of mechanical agitation, power ultrasound on impurity removal and waste volume reduction, (4) investigate the benefits of PFC on removal of microorganisms, and (5) study impurity distribution in ice. The results of this study are expected to provide new insight into the mechanisms of impurity separation by PFC and better design of the PFC systems for wastewater treatment.

二次工业废水（例如炼油厂、纸浆造纸厂的废水）和反渗透和纳滤厂的膜浓缩液（包括被膜阻挡的污染物、清洗液和反洗水）中的大多数污染物都是溶解形式，有些还含有有毒化合物。目前，大多数膜厂直接将浓缩液排放到地表水或生活污水管中。需要采用多级预处理工艺进行深度处理以去除溶解固体，而蒸发或焚烧往往是某些废水残渣/污泥减容处置的唯一选择。与这些先进处理方案相关的高运营和资本成本以及复杂的操作限制了它们的实际应用。冷冻浓缩由于其独特的能力，可以去除溶解的杂质，在不添加任何化学品和预处理的情况下减少废物量，还可以回收纯净水流，在这些领域具有巨大的应用潜力。与传统的悬浮结晶方法不同，渐进冷冻浓缩（PFC）需要简化的操作系统来从给水中分离冰晶，因此可以大大降低工艺成本。然而，目前尚未对PFC浓缩效率的机理进行系统研究，并且可用于废水处理PFC工艺工程设计的信息也很少。通过本研究项目将进行实验室实验：（1）研究选定废水和膜浓缩液的冷冻特性及其对PFC的影响，（2）确定PFC的杂质去除效率、毒性降低和减容能力，（3）检查机械搅拌、功率超声对杂质去除和废物减容的效果，（4）研究PFC去除的益处 （5）研究冰中杂质的分布。这项研究的结果有望为 PFC 杂质分离机制提供新的见解，并更好地设计用于废水处理的 PFC 系统。