Globally eruptive harmful algal blooms (HABs) have caused numerous negative effects on aquatic ecosystem and human health. Conversion of HABs into biohythane via dark fermentation (DF) is a promising approach to simultaneously cope with environmental and energy issues, but low HABs harvesting efficiency and biohythane productivity severely hinder its application. Here we designed a gradient electro-processing strategy for efficient HABs harvesting and disruption, which had intrinsic advantages of no secondary pollution and high economic feasibility. Firstly, low current density (0.888-4.444 mA/cm²) was supplied to HABs suspension to harvest biomass via electro-flocculation, which achieved 98.59% harvesting efficiency. A mathematic model considering coupling effects of multi-influencing factors on HABs harvesting was constructed to guide large-scale application. Then, the harvested HABs biomass was disrupted via electro-oxidation under higher current density (44.44 mA/cm²) to improve bioavailability for DF. As results, hydrogen and methane yields of 64.46 mL/ (g VS) and 171.82 mL/(g VS) were obtained under 6 min electro-oxidation, along with the highest energy yield (50.1 kJ/L) and energy conversion efficiency (44.87%). Mechanisms of HABs harvesting and disruption under gradient electro-processing were revealed, along with the conversion pathways from HABs to biohythane. Together, this work provides a promising strategy for efficient disposal of HABs with extra benefit of biohythane production.

全球爆发的有害藻华 (HAB) 对水生生态系统和人类健康造成了许多负面影响。通过暗发酵 (DF) 将 HABs 转化为生物乙烷是一种同时应对环境和能源问题的有前景的方法，但低 HABs 收获效率和生物乙烷生产率严重阻碍了其应用。在这里，我们设计了一种用于高效收获和破坏 HAB 的梯度电处理策略，该策略具有无二次污染和高经济可行性的内在优势。首先，低电流密度（0.888-4.444 mA/cm ²) 提供给 HABs 悬浮液，通过电絮凝收获生物质，达到 98.59% 的收获效率。构建了考虑多影响因素对HABs收获的耦合效应的数学模型，以指导大规模应用。然后，收获的HABs生物质在较高电流密度（44.44 mA/cm ²) 以提高 DF 的生物利用度。结果，在电氧化 6 min 下，氢气和甲烷的产率分别为 64.46 mL/(g VS) 和 171.82 mL/(g VS)，以及最高的能量产率 (50.1 kJ/L) 和能量转换效率 (44.87) %）。揭示了梯度电处理下 HABs 的收获和破坏机制，以及从 HABs 到生物乙烷的转化途径。总之，这项工作为高效处置 HAB 提供了一种有前景的策略，并具有生物乙烷生产的额外好处。