Dataset associated to publication: " High-rate biological selenate reduction in a sequencing batch reactor for recovery of hexagonal selenium "

Results belonging to paper "High-rate biological selenate reduction in a sequencing batch reactor for recovery of hexagonal selenium".Recovery of selenium (Se) from wastewater provides a solution for both securing Se supply and preventing Se pollution. Here, we developed a high-rate process for biological selenate reduction to elemental selenium. Distinctive from other studies, we aimed for a process with selenate as the main biological electron sink, with minimal formation of methane or sulfide. A sequencing batch reactor, fed with an influent containing 120 mgSe L^-1 selenate and ethanol as electron donor and carbon source, was operated for 495 days. The high rates (419 ± 17 mgSe L^-1 day^-1) were recorded between day 446 and day 495 for a hydraulic retention time of 6h. The maximum conversion efficiency of selenate amounted to 96% with a volumetric conversion rate of 444 mgSe L^-1 day^-1, which is 6 times higher than the rates reported in the literature thus far. At the end of the experiment, a highly enriched selenate reducing biomass had developed, with a specific activity of 856±26 mgSe^-1day^-1g_biomass^-1, which was nearly 1000-fold higher than that of the inoculum. No evidence was found for the formation of methane, sulfide, or volatile reduced selenium compounds like dimethyl-selenide or H₂Se, revealing a high selectivity. Ethanol was incompletely oxidized to acetate. The produced elemental selenium partially accumulated in the reactor as pure (≥80% Se of the total mixture of biomass sludge flocs and flaky aggregates, and ~100% of the specific flaky aggregates) selenium black hexagonal needles, with cluster sizes between 20-200 µm. The new process may serve as the basis for a high-rate technology to remove and recover pure selenium from wastewater or process streams with high selectivity.<br>

本研究结果来自论文《序批式反应器中高效生物还原硒酸盐回收六方单质硒》（High-rate biological selenate reduction in a sequencing batch reactor for recovery of hexagonal selenium）。从废水中回收硒（Se）既能保障硒资源供给，又可防控硒污染。本研究开发了一种以生物还原硒酸盐生成单质硒的高效工艺。与其他研究不同，本工艺以硒酸盐作为主要生物电子受体，尽可能减少甲烷或硫化物的生成。实验采用序批式反应器（Sequencing Batch Reactor, SBR），进水含120 mgSe·L⁻¹硒酸盐及乙醇作为电子供体与碳源，连续运行495天。在水力停留时间（Hydraulic Retention Time, HRT）为6小时的条件下，第446至495天期间测得容积负荷为(419±17) mgSe·L⁻¹·d⁻¹。硒酸盐的最大转化效率达96%，体积转化速率为444 mgSe·L⁻¹·d⁻¹，较迄今文献报道的速率高出6倍。实验末期，反应器内富集得到高活性硒酸盐还原生物量，比活达(856±26) mgSe·g⁻¹生物量·d⁻¹，较接种污泥的比活提升近1000倍。未检测到甲烷、硫化物或二甲基硒化物、硒化氢（H₂Se）等挥发性还原硒化合物的生成，表明该工艺具有极高选择性。乙醇未被完全氧化，仅转化为乙酸盐。生成的单质硒部分在反应器内富集，形成纯相（≥80% Se占生物污泥絮体与片状聚集体总混合物的比例，片状聚集体中Se占比约100%）的黑色六方硒针状晶体，聚集体尺寸介于20~200 μm之间。该新工艺可作为一种高效技术的基础，用于高选择性地从废水或工艺流中去除并回收纯硒单质。