Department of Civil and Environmental Engineering , Stanford University , Stanford , California 94305-4020 , United States.
ReNUWIt , National Science Foundation Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure , Stanford , California 94305-4020 , United States.
Environ Sci Technol. 2019 Mar 19;53(6):3128-3139. doi: 10.1021/acs.est.9b00184. Epub 2019 Feb 26.
To address water scarcity, cities are pursuing options for augmenting groundwater recharge with recycled water. Ozone-based treatment trains comprising ozone and biologically activated carbon potentially offer cost-effective alternatives to membrane-based treatment, the standard process for potable reuse in numerous countries. However, regulations in multiple states effectively limit the extent to which ozone-based treatment alone can produce recycled water for groundwater recharge. To investigate the trade-offs between treatment costs and regulatory constraints, this study presents methods for modeling and optimizing designs for (1) producing recycled water using membrane-based treatment, ozone-based treatment, and hybrid treatment trains comprising ozone-based treatment with a membrane sidestream, and (2) delivering that water to stormwater spreading basins. We present a case study of Los Angeles, CA, to demonstrate the model's application under realistic conditions, including regulations that limit spreading recycled water based on its concentration of total organic carbon and the extent of dilution. While the membrane-based treatment train exhibits economies of scale, we demonstrate how regulatory constraints create a diseconomies of scale effect for hybrid treatment systems because larger scales necessitate a higher proportion of recycled water undergo membrane treatment. Nevertheless, relative to membrane-based treatment, we identify opportunities for ozone-based or hybrid treatment trains to reduce treatment costs and energy use by up to 62% and 59%, respectively, for systems with up to 1 m/s (23 million gallons per day) mean water recycling rate, potentially lowering the barrier for decentralized water recycling systems. This modeling approach could inform planning and policy regarding recycled water projects for groundwater recharge through spreading basins and, with additional modification, other potable reuse applications.
为了解决水资源短缺问题，城市正在寻求利用再生水来增加地下水补给的方法。基于臭氧的处理系统包括臭氧和生物活性炭，与膜基处理相比，具有成本效益的替代方法，膜基处理是许多国家饮用水再利用的标准工艺。然而，多个州的法规实际上限制了仅基于臭氧的处理单独生产可用于地下水补给的再生水的程度。为了研究处理成本和监管限制之间的权衡，本研究提出了用于建模和优化设计的方法：(1) 使用膜基处理、基于臭氧的处理和包括臭氧基处理与膜侧流的混合处理系统生产再生水；(2) 将该水输送到雨水漫流盆地。我们以加利福尼亚州洛杉矶为例，演示了该模型在现实条件下的应用，包括根据总有机碳浓度和稀释程度限制再利用水扩散的法规。虽然膜基处理系统具有规模经济，但我们展示了监管限制如何为混合处理系统创造规模不经济效应，因为更大的规模需要更高比例的再生水经过膜处理。然而，与膜基处理相比，我们确定了基于臭氧或混合处理系统有机会降低处理成本和能源使用，对于处理量高达 1 m/s（2300 万加仑/天）的系统，分别可降低 62%和 59%，这可能降低了分散式水回收系统的障碍。这种建模方法可以为通过漫流盆地进行地下水补给的再生水项目的规划和政策提供信息，并通过进一步修改，为其他饮用水再利用应用提供信息。
