College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
Water Res. 2020 May 1;174:115642. doi: 10.1016/j.watres.2020.115642. Epub 2020 Feb 21.
Phytoremediation of reverse osmosis concentrate (ROC) with microalgae can simultaneously achieve multi-functions of ROC treatment, CO mitigation and microalgae biolipid production. But the performances are usually inhibited by high free ammonia nitrogen (FAN) concentration and chromaticity of ROC. To offset these negative effects, an integrated technique including electrooxidation pretreatment and Chlorella vulgaris remediation was proposed, in which the ROC was first pretreated with electrooxidation to decrease FAN and chromaticity, and then the oxidized ROC was remediated with microalgae to reclaim nutrients and produce biolipid. Results showed that FAN was sharply reduced from 53.0 mg N/L to 13.9 mg N/L and chromaticity was decreased from 1600 to 100 Pt-Co via electrooxidation. Possible reaction mechanism of nutrients removal was discussed via electron mass balance. Explanation on chromaticity decrease was revealed by analyzing humic acid conversion path with fluorescence characteristics. During microalgae remediation process, nutrients removal rate, microalgae biomass concentration and lipid yield were effectively enhanced in electrooxidized ROC. Energy balance analysis indicated that microalge lipid energy under current density of 3.25 mA/cm basically compensated total input energy despite ROC sterilization. This work provided a promising strategy for large-scale ROC treatment and microalgae biolipid production.
利用微藻对反渗透浓缩液（ROC）进行植物修复可以同时实现 ROC 处理、CO 减排和微藻生物脂质生产等多种功能。但由于 ROC 中高浓度游离氨氮（FAN）和色度的存在，其性能通常受到抑制。为了抵消这些负面影响，提出了一种包括电氧化预处理和小球藻修复的集成技术，其中 ROC 首先通过电氧化预处理来降低 FAN 和色度，然后用微藻修复氧化后的 ROC 以回收营养物质并生产生物脂质。结果表明，电氧化可将 FAN 从 53.0mg N/L 急剧降低至 13.9mg N/L，色度从 1600 降低至 100Pt-Co。通过电子质量平衡讨论了去除营养物的可能反应机制。通过分析荧光特性揭示了腐殖酸转化途径来解释色度降低的原因。在微藻修复过程中，电氧化 ROC 中营养物去除率、微藻生物量浓度和产油量都得到了有效提高。能量平衡分析表明，在 3.25mA/cm2 的电流密度下，微藻脂质能量基本可以补偿 ROC 灭菌的总输入能量。这项工作为大规模 ROC 处理和微藻生物脂质生产提供了一种很有前途的策略。
