In this study, the impacts of various iron-based additives on anaerobic digestion of biomass and the fate of the iron-rich digestates on the ecosystem were reviewed. Anaerobic digestion of biomass is a green energy technology with known environmental benefits for biogas production. However, increasing interest in this technology has triggered the need to improve biogas yield from existing substrates and to enhance the biodegradability of biomasses of lignocellulosic (≥70%), complex molecular nature, and novel substrates, necessitating the use of several enhancement techniques. Among the enhancement options, the influence of iron-based additives on methanogens as it relates to their electron donation/acceptor capabilities and as a cofactor of key enzymatic activities have been highlighted as being outstanding in enhancing anaerobic digestion processes. The reviewed iron-based additives classified based on their forms were either synthesized or naturally occurred as liquids, nanoparticles, solids or powders and applied to bio-digestion processes at different dosages. These reviewed iron-based additives were reported to have influenced biogas yields and methane contents, solids and volatile fatty acids, reduction of antibiotic-resistant genes (ARGs), pathogens, and pharmaceutical and personal care products (PPCPs), etc. Aside these proven benefits, the environmental implications of non-degradability of iron complexes formed during iron supplemented anaerobic digestion and their fate after digestates disposal calls for concern. However, this study recommends that research on the use of cross-linkers, extra-polymeric substances and antagonists alongside iron-based additives could play a vital role in preventing up to 90% iron complexes formation while enhancing biogas yields.

在这项研究中，审查了各种铁基添加剂对生物质厌氧消化的影响以及富铁消化物对生态系统的命运。生物质的厌氧消化是一种绿色能源技术，对于沼气生产具有已知的环境效益。但是，对这项技术的兴趣不断提高，引发了提高现有底物沼气产量并提高木质纤维素（≥70％），复杂分子性质和新型底物生物质的生物降解性的需要，因此必须使用多种增强技术。在增强选项中，铁基添加剂对产甲烷菌的影响，因为它与电子供体/受体能力有关，并且作为关键酶活性的辅助因子，在增强厌氧消化过程中表现突出。审查了根据其形式分类的铁基添加剂，可以合成它们或以液体，纳米颗粒，固体或粉末形式自然存在，并以不同的剂量应用于生物消化过程。据报道，这些经过审查的铁基添加剂已影响沼气产量和甲烷含量，固体和挥发性脂肪酸，抗生素抗性基因（ARG），病原体以及药品和个人护理产品（PPCP）的减少等。好处，补充铁的厌氧消化过程中形成的铁配合物不可降解的环境影响及其在消化后的命运值得关注。但是，这项研究建议，关于将交联剂，超聚合物质和拮抗剂与铁基添加剂一起使用的研究，在防止多达90％的铁络合物形成并提高沼气产量的过程中，可能起着至关重要的作用。