Department of Global Smart City, Sungkyunkwan University (SKKU), 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
Graduate School of Water Resources, Sungkyunkwan University (SKKU), 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
Chemosphere. 2024 Oct;366:143426. doi: 10.1016/j.chemosphere.2024.143426. Epub 2024 Sep 26.
This study investigated the use of polyvinyl alcohol (PVA) cryogels to immobilize microalgae for wastewater treatment. Chlorella sorokiniana was successfully entrapped in PVA cryogels via repeated freeze/thaw cycles. The nutrient removal efficiency of these cryogels was tested in a continuously stirred photobioreactor under varying conditions, both with and without the addition of an organic carbon source (sodium acetate). The presence of organic carbon significantly enhanced nutrient removal. Specifically, PVA cryogels with immobilized C. sorokiniana achieved 100% nitrogen removal and 97.2% phosphorus removal under mixotrophic conditions. Furthermore, the maximum nutrient removal capacities of the PVA cryogels were found to be 0.033 mg-N/cube·day for nitrogen and 0.0047 mg-P/cube·day for phosphorus. As the inorganic carbon (bicarbonate) concentration increased from 5 to 100 mg/L, the N/P ratio rose from 6 to 8, with a higher N/P ratio of 10 observed when nitrate nitrogen was used as the nitrogen source, compared to ammonia nitrogen, at 100 mg/L bicarbonate. This study offers an effective method for using microalgae immobilized in PVA cryogels for wastewater treatment. The findings highlight the potential for PVA cryogels to significantly improve nutrient removal efficiency, particularly in the presence of organic carbon sources, thereby enhancing bioreactor performance. High nitrogen and phosphorus removal efficiencies can help reduce eutrophication in water bodies, protect aquatic ecosystems, and enable nutrient recovery and reuse, supporting a circular economy in wastewater treatment practices.
本研究探讨了使用聚乙烯醇（PVA）冷冻凝胶来固定微藻以处理废水。通过反复的冷冻/解冻循环，成功地将小球藻固定在 PVA 冷冻凝胶中。在连续搅拌光生物反应器中，在不同条件下测试了这些冷冻凝胶的营养物去除效率，包括有无添加有机碳源（乙酸钠）。有机碳的存在显著提高了营养物去除效率。具体来说，在混合营养条件下，固定有小球藻的 PVA 冷冻凝胶实现了 100%的氮去除率和 97.2%的磷去除率。此外，PVA 冷冻凝胶的最大营养物去除容量被发现分别为 0.033 mg-N/cube·day（氮）和 0.0047 mg-P/cube·day（磷）。随着无机碳（碳酸氢盐）浓度从 5 增加到 100 mg/L，N/P 比从 6 增加到 8，当使用硝酸盐氮作为氮源时，在 100 mg/L 碳酸氢盐条件下观察到更高的 N/P 比为 10，而当使用氨氮作为氮源时，N/P 比为 10。本研究提供了一种使用固定在 PVA 冷冻凝胶中的微藻处理废水的有效方法。研究结果表明，PVA 冷冻凝胶具有显著提高营养物去除效率的潜力，特别是在存在有机碳源的情况下，从而提高生物反应器的性能。高氮和磷去除效率有助于减少水体富营养化，保护水生生态系统，并实现营养物回收和再利用，支持废水处理实践中的循环经济。
