Department of Soil and Water Systems, University of Idaho, Moscow, Idaho, USA.
Department of Chemical and Biological Engineering, University of Idaho, Moscow, Idaho, USA.
Water Environ Res. 2023 Sep;95(9):e10926. doi: 10.1002/wer.10926.
Biochar (BC) use in water treatment is a promising approach that can simultaneously help address societal needs of clean water, food security, and climate change mitigation. However, novel BC water treatment technology approaches require operational testing in field pilot-scale scenarios to advance their technology readiness assessment. Therefore, the objective of this study is to evaluate the system performance of BC integrated into hydrous ferric oxide reactive filtration (Fe-BC-RF) with and without catalytic ozonation (CatOx) process in laboratory and field pilot-scale scenarios. For this investigation, Fe-BC-RF and Fe-CatOx-BC-RF pilot-scale trials were conducted on synthetic lake water variants and at three municipal water resource recovery facilities (WRRFs) at process flows of 0.05 and 0.6 L/s, respectively. Three native and two iron-modified BCs were used in these studies. The commercially available reactive filtration process (Fe-RF without BC) had 96%-98% total phosphorus (TP) removal from 0.075- and 0.22-mg/L TP, as orthophosphate process influent in these trials. With BC integration, phosphorus removal yielded 94%-98% with the same process-influent conditions. In WRRF field pilot-scale studies, the Fe-CatOx-BC-RF process removed 84%-99% of influent total phosphorus concentrations that varied from 0.12 to 8.1 mg/L. Nutrient analysis on BC showed that the recovered BC used in the pilot-scale studies had an increase in TP from its native concentration, with the Fe-amended BC showing better P recovery at 110% than its unmodified state, which was 16%. Lastly, the field WRRF Fe-CatOx-BC-RF process studies showed successful destructive removals at >90% for more than 20 detected micropollutants, thus addressing a critical human health and environmental water quality concern. The research demonstrated that integration of BC into Fe-CatOx-RF for micropollutant removal, disinfection, and nutrient recovery is an encouraging tertiary water treatment technology that can address sustainable phosphorus recycling needs and the potential for carbon-negative operation. PRACTITIONER POINTS: A pilot-scale hydrous ferric oxide reactive sand filtration process integrating biochar injection typically yields >90% total phosphorus removal to ultralow levels. Biochar, modified with iron, recovers phosphorus from wastewater, creating a P/N nutrient upcycled soil amendment. Addition of ozone to the process stream enables biochar-iron-ozone catalytic oxidation demonstrating typically excellent (>90%) micropollutant destructive removals for the compounds tested. A companion paper to this work explores life cycle assessment (LCA) and techno-economic analysis (TEA) to explore biochar water treatment integrated reactive filtration impacts, costs, and readiness. Biochar use can aid in long-term carbon sequestration by reducing the carbon footprint of advanced water treatment in a dose-dependent manner, including enabling an overall carbon-negative process.
生物炭（BC）在水处理中的应用是一种很有前途的方法，它可以同时帮助满足清洁水、食品安全和气候变化缓解的社会需求。然而，新型 BC 水处理技术方法需要在现场中试规模场景中进行运行测试，以推进其技术就绪评估。因此，本研究的目的是评估在实验室和现场中试规模场景中，将生物炭集成到水合氧化铁反应过滤（Fe-BC-RF）中，以及是否具有催化臭氧化（CatOx）过程的系统性能。为此，在过程流速分别为 0.05 和 0.6 L/s 的情况下，对合成湖水变体和三个城市水资源回收厂（WRRF）进行了 Fe-BC-RF 和 Fe-CatOx-BC-RF 中试试验。在这些研究中使用了三种天然和两种铁改性的生物炭。商业上可用的反应过滤过程（无 BC 的 Fe-RF）在这些试验中，将 0.075- 和 0.22-mg/L TP 作为正磷酸盐工艺进水，从 0.075- 和 0.22-mg/L TP 中去除了 96%-98%的总磷（TP）。通过集成 BC，在相同的工艺进水条件下，磷的去除率达到 94%-98%。在 WRRF 现场中试研究中，Fe-CatOx-BC-RF 工艺去除了进水总磷浓度的 84%-99%，进水总磷浓度从 0.12 到 8.1mg/L 不等。对 BC 的营养分析表明，从中试研究中回收的 BC 与其原始浓度相比，TP 有所增加，Fe 改性 BC 的磷回收效果比其未改性状态更好，为 110%，而未改性状态为 16%。最后，现场 WRRF Fe-CatOx-BC-RF 工艺研究表明，对于超过 20 种检测到的微量污染物，超过 90%的成功破坏性去除，从而解决了一个关键的人类健康和环境水质问题。该研究表明，将 BC 集成到 Fe-CatOx-RF 中以去除微量污染物、进行消毒和回收营养物是一种有前途的三级水处理技术，可以满足可持续磷回收的需求，并有可能实现负碳运行。从业者要点： 集成生物炭注入的水合氧化铁反应砂滤中试规模工艺通常可将总磷去除到超低水平，去除率>90%。 经过铁改性的生物炭从废水中回收磷，形成磷氮养分升级的土壤改良剂。 在工艺流中添加臭氧可实现生物炭-铁-臭氧催化氧化，通常对测试化合物表现出优异的（>90%）微量污染物破坏性去除效果。 本工作的一篇配套论文探讨了生命周期评估（LCA）和技术经济分析（TEA），以探索集成生物炭水处理的反应过滤的影响、成本和准备情况。 生物炭的使用可以通过减少高级水处理的碳足迹，以剂量依赖的方式帮助实现长期的碳封存，包括实现整体负碳过程。
