both biogas upgrading and biogas slurry nutrient removal was the red:blue ratio of 5:5. Lower influent CH4 (methane …) concentration achieved higher biogas slurry nutrient removal efficiency, whereas moderate influent CH4 concentration achieved the … biogas slurry nutrient purification effects with the following values: 92.60 ± 2.24% (v/v) of upgraded biogas CH4 …