臭氧组合絮凝工艺处理牛粪沼液的研究

牛粪沼液作为集约化规模化养殖业阶段处理的产物,产量巨大,有限的土地不足以消纳所有沼液从而导致还田利用十分困难。因此急需寻求一种沼液的预处理方法,实现其固液分离,减少固絮物后续处置量,同时上清液经处理后达标排放。臭氧氧化将大分子有机物降解为小分子物质,絮凝处理可以很好地提高沼液内部固体颗粒的沉降性能,以实现后续上清液的深度处理。该研究采用臭氧+絮凝工艺对牛粪沼液进行预处理,结果表明,单独臭氧处理中,当pH值为7.8,臭氧曝气时间为40 min,臭氧投加速率为2.2 g·h-1时,COD去除率可以达到46%;臭氧+絮凝处理中,当pH值为8.3,搅拌时间为2 min,搅拌速率为300 r·min-1,静置时间为15 min,投药量/总固体TS=1.5,最佳沉降比达到14%,极大地提升了沉降性能,总COD去除率最佳达到82%,最终COD降低到4000 mg·L-1左右,同时为后续处理减轻了负荷,对实际处理有较强的借鉴意义。

Ozonation and Flocculation Combination Treating Biogas Slurry of Cow Dung

Biogas slurry as the product of intensive large-scale breeding,the limited land is not enough to absorb.Therefore,it is urgent to seek a method for digestate to separation the solid and liquid,and reduce the follow-up disposal amount of solid flocs,and the supernatant could be discharged after treatment.Ozone can degrade large molecular organics into small molecules.Flocculation treatment can improve the sedimentation of solid particles in digestate.In this study,ozone+flocculation combination were used to pretreat cow dung digestate.The results showed that,in the sole ozone treatment,when pH 7.8,ozone aeration time 40min,and ozone adding rate 2.2 g·h-1,COD removal rate could reach 46%.For ozone+flocculation process,when the pH was 8.3,stirring 2 min,stirring speed 300 r·min-1,standing for 15 min,and aluminum chloride dosage/TS was 1.5,the best settlement ratio reaches 14%,greatly improved the sedimentation performance,the total removal rate of COD reached 82%,the final COD could be reduced to about 4000 mg·L-1.In this way,it can reduce the load for subsequent treatment and has strong reference to the actual processing.