Abstract The sago industrial liquid waste is rich in Nitrate and Phosphate and thus need to be processed before being flown to environment. A study aims to reduce the nitrate and phosphate in that sago liquid waste by using biofilter that was added with Effective Microorganisms-4 has been conducted in April-May 2019. There were 3 treatments applied, namely the addition of 17 mL, 20 mL, and 2…