Cranfield Water Sciences Institute, College Road, Cranfield, Bedford MK43 0AL, United Kingdom.
Kompetenzzentrum Wasser Berlin, Cicerostraße 24, 10709 Berlin, Germany.
Sci Total Environ. 2021 Aug 20;783:146834. doi: 10.1016/j.scitotenv.2021.146834. Epub 2021 Mar 30.
This study was completed to understand the resilience of an ion exchange (IEX) process for its ability to remove variable ammonium (NH-N) loads) and to prove its environmental benefits through a life cycle assessment (LCA). The tertiary 10 m/day demonstration scale IEX was fed with variable NH-N concentrations (<0.006-26 mg NH-N /L) naturally found in municipal wastewater. Zeolite-N was used as ion exchange media and regeneration was completed with 10% potassium chloride (KCl). The influent NH-N concentration impacted the ion exchange capacity, which ranged from 0.9-17.7 mg NH-N/g media. When the influent concentration was <2.5 mg NH-N/L, the Zeolite-N released NH-N (up to 12%). However, the exchange increased up to 62% when the influent NH-N load peaked, confirming the resilience of the process. A 94% regeneration efficiency was obtained with fresh regenerant, however, with the increase of the mass of NH-N on the media, the regeneration efficiency decreased. An optimisation of the volume of brine and regeneration contact time is suggested. To further measure the benefits of the IEX process, an LCA was conducted, for a 10,000 population equivalent reference scenario, and compared with traditional nitrification-denitrification WWTP. The LCA revealed that IEX with regenerant re-use and NH-N recovery through a membrane stripping process resulted in reductions of: 25% cumulative energy demand; 66% global warming potential and 62% marine eutrophication potential, when compared to traditional WWTP. This work demonstrated that the IEX process is an efficient and an environmentally benign technology that can be widely applied in WWTPs.
本研究旨在了解离子交换（IEX）工艺的弹性，以了解其去除可变铵（NH-N）负荷的能力，并通过生命周期评估（LCA）证明其环境效益。三级 10 立方米/天的示范规模 IEX 以市政废水中天然存在的可变 NH-N 浓度（<0.006-26mg NH-N/L）为进料。沸石-N 用作离子交换介质，用 10%氯化钾（KCl）完成再生。进水 NH-N 浓度影响离子交换容量，范围为 0.9-17.7mg NH-N/g 介质。当进水浓度<2.5mg NH-N/L 时，沸石-N 释放 NH-N（高达 12%）。然而，当进水 NH-N 负荷达到峰值时，交换增加了 62%，证实了该过程的弹性。新鲜再生剂的再生效率达到 94%，但是，随着介质上 NH-N 质量的增加，再生效率降低。建议优化盐水的体积和再生接触时间。为了进一步衡量 IEX 工艺的好处，进行了生命周期评估，对于 10000 人口当量的参考情景，并与传统的硝化-反硝化 WWTP 进行了比较。生命周期评估表明，对于再生剂再利用和通过膜汽提过程回收 NH-N 的 IEX，与传统 WWTP 相比，累计能源需求减少了 25%，全球变暖潜势减少了 66%，海洋富营养化潜势减少了 62%。这项工作表明，IEX 工艺是一种高效且环境友好的技术，可广泛应用于 WWTP。
