为削减沼液处理工艺中生物生态单元的负荷，采用磁混凝工艺预处理沼液。经单因素和响应面试验优化磁种与混凝剂的投加配比，分析混凝出水中的残余铝含量和铝形态以及有机物官能团的分布，研究磁混凝强化沼液预处理的效能与磁混凝机理。结果表明，磁混凝加快絮体沉降，提高出水安全性，增加沼液中污染物去除；磁混凝预处理最佳配比为Fe3O4（1.0 g·L-1）+Al2(SO4)3（2.05 g·L-1）+PAM（10.34 mg·L-1），此时磷、COD和氨氮去除率分别达到99.09%、30.39%和14.76%。同时磁混凝通过促进Alb的生成和增强芳香碳物质去除的方式强化沼液中有机物去除；另外磁种Fe3O4的吸附增加氨氮去除。结果可为沼液预处理提供技术参考。
In order to reduce the pollutant loading of bio-ecological units in the biogas slurry treatment process, the magnetic coagulation process was adopted to pre-treat the biogas slurry in this paper. The dosage of magnetic seeds and coagulations was first optimized by single-factor and response surface experiments, and then process performance and mechanism were explored by analyzing Al content and Al species of coagulation effluent and the distribution of organic functional groups from coagulation flocs. The results showed that magnetic coagulation accelerated the settling of flocs, improved the safety of effluent, and strengthened the removal of pollutants. The optimal coagulant composition for magnetic coagulation was Fe3O4(1.0 g·L-1)+Al2(SO4)3(2.05 g·L-1)+PAM (10.34mg·L-1), and the removal efficiency of PO43--P, COD, and NH4+-N respectively reached 99.09%, 30.39%, and 14.76%, at this level. At the same time, the removal of organic matter was enhanced at magnetic coagulation in biogas slurry by promoting Alb species generation and improving aromatic carbon compounds removal. Besides, the magnetic adsorption improved NH4+-N removal during coagulation. The results provide technical references for biogas slurry pretreatment.