Abstrak Restaurant liquid waste is rich in BOD5 dan COD and thus needs to be processed before being flown to environment. A study aims to reduce the BOD5 dan COD in that waste by using the biofilter that was added with EM4 has been conducted in May-Juny 2019. A Completely Randomized Design (CRD) with 3 treatments, without EM4 (P0), addition of 7.5 ml EM4 (P1), 10 ml EM4 (P2) and 12.5 ml E…