The combined pollution and oligotrophic characteristics of surface water led to poor self-purification capacity of water bodies. In this study, humic acid (HA) and fulvic acid (FA) were used to promote the denitrification process of strain Zoogloea sp. ZP7. Subsequently, iron and different humus (HA and FA) composites were encapsulated by polyvinyl alcohol (PVA) and sodium alginate (SA) to prepare two biological immobilization (BI) carriers Fe-HA@PVA/SA (FHB) and Fe-FA@PVA/SA (FFB), which immobilized strain ZP7. The BI materials were added to the water remediation system model and operated for three stages (synthetic wastewater, actual polluted surface water, sediment-contaminated surface water) for 48 days. The results showed that FHB (FFB) could remove up to 89.7 % (88.6 %), 90.5 % (89.5 %), 82.2 % (81.5 %), and 90.4 % (80.8 %) of total nitrogen, nitrate, COD_Mn, and phosphate from the actual polluted surface water within 16 days of stage II. In addition, the incorporation of FHB and FFB was effective in controlling the release of organic matter and heavy metals from the sediments. Microbial community analysis showed that Zoogloea became the dominant species in actual water bodies. KEGG database analysis illustrated that the expression of genes related to denitrification and iron redox cycle was enhanced. This work provides a novel approach into the in-situ bioremediation of actual nutrient-poor water bodies.

中文翻译：

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含铁腐殖质生物固定化材料对贫营养水域的生物修复：性能和可能的机制


地表水的污染和寡营养特性相结合，导致水体的自我净化能力差。本研究采用腐植酸 （HA） 和黄腐酸 （FA） 促进菌株 Zoogloea sp. ZP7 的反硝化过程。随后，用聚乙烯醇 （PVA） 和海藻酸钠 （SA） 包封铁和不同的腐殖质 （HA 和 FA） 复合材料，制备两种生物固定化 （BI） 载体 Fe-HA@PVA/SA （FHB） 和 Fe-FA@PVA/SA （FFB），固定化菌株 ZP7。BI 材料被添加到水修复系统模型中，并运行三个阶段（合成废水、实际污染的地表水、沉积物污染的地表水），为期 48 天。结果表明，FHB （FFB） 可在 II 阶段 16 天内从实际受污染的地表水中去除高达 89.7 % （88.6 %）、90.5 % （89.5 %）、82.2 % （81.5 %） 和 90.4 % （80.8 %） 的总氮、硝酸盐、COD_Mn 和磷酸盐。此外，FHB 和 FFB 的掺入可有效控制沉积物中有机物和重金属的释放。微生物群落分析表明，Zoogloea 成为实际水体中的优势物种。KEGG 数据库分析表明，与反硝化和铁氧化还原循环相关的基因表达增强。这项工作为实际营养贫乏水体的原位生物修复提供了一种新方法。