Electro-fermentation (EF) is a promising technology for extracting valuable metabolites from waste biomass, while its effectiveness for phosphorus recovery has received little attention. In this study, we investigated the impact of different iron sources, i.e., FeCl₃, FeOOH, Fe₂O₃, zero-valent iron (ZVI), a built-in Fe anode, and stainless-steel mesh (SSM), on concurrent biohydrogen and vivianite (Fe₃(PO₄)₂·8H₂O) recovery from sludge fermentation liquid (SFL) in an EF system. Results indicated that the Fe anode group achieved the highest hydrogen productivity of 17.7 mmol/g COD at 5 d, which was 101–743% higher than that of other iron sources. The utilization efficiency of short-chain fatty acids (SCFAs) peaked at 79.1% within 5 d, which was 1.2 folds higher than that of Control (without iron addition). Moreover, the phosphate removal efficiency reached 100% within 2 d and 5 d in Fe anode and SSM group, respectively, while the other groups achieved only 0–39.4% removal. SEM and XRD analyses demonstrated the existence of vivianite particles in the recovered products in the groups of FeCl₃, FeOOH and Fe anode. Electrochemically active bacteria (EAB), e.g., Geobacter, Comamonas, and Desulfovibrio, accounted for 3.6–60.2% of all groups. Geobacter, Azospira, Comamonas, and Desulfovibrio, which are also considered dissimilatory iron reducing bacteria (DIRB), were enriched to 0.1–40.7% in all groups. Acetoanbacterium and Acetoaerobium, typical homo-acetogens, were enriched to 78.0% in the Fe anode group, while was only 9.0–29.3% in other groups. Correlation and molecular ecological network (MEN) analyses of the functional microbial consortia further indicated the intertrophic interaction. This study provides a theoretical basis for synchronous hydrogen and phosphorus recovery from WAS in the further industrial implementation.

电发酵（EF）是一种从废弃生物质中提取有价值代谢物的有前景的技术，但其磷回收的有效性却很少受到关注。在本研究中，我们研究了不同铁源（即 FeCl ₃、FeOOH、Fe ₂ O ₃、零价铁 (ZVI)、内置 Fe 阳极和不锈钢网 (SSM)）对并发生物氢和紫铁矿(Fe ₃ (PO ₄ ) ₂ ·8H ₂O) 从 EF 系统中的污泥发酵液 (SFL) 中回收。结果表明，Fe阳极组在5 d时实现了最高的产氢能力，为17.7 mmol/g COD，比其他铁源高101-743%。短链脂肪酸（SCFA）的利用率在5 d内达到峰值79.1%，比对照（不添加铁）高1.2倍。此外，Fe阳极和SSM组的磷酸盐去除率分别在2 d和5 d内达到100%，而其他组仅达到0-39.4%的去除率。_{SEM和XRD分析表明FeCl 3} 、FeOOH和Fe阳极组的回收产物中存在钒铁矿颗粒。电化学活性细菌 (EAB)，例如地杆菌属、丛毛单胞菌属，和脱硫弧菌，占所有组的3.6-60.2%。地杆菌属、固氮螺菌属、丛毛单胞菌属和脱硫弧菌属也被认为是异化铁还原菌 (DIRB)，在所有组中均富集至 0.1-40.7%。典型的同型产乙酸菌醋酸杆菌和醋酸需氧菌在 Fe 阳极组中富集至 78.0%，而在其他组中仅为 9.0-29.3%。功能微生物群落的相关性和分子生态网络（MEN）分析进一步表明了营养间的相互作用。该研究为WAS同步回收氢磷的进一步工业化实施提供了理论依据。