481 10.4 10.4 10.6 ) g-COD) (10.21) Nualsri , 2016; Sittijunda Reungsang, 2012) COD balance = COD balance CODdistribution CODinitial CODdistribution x100 - 100 10.21) CODinitial COD COD g-COD/L) COD g-COD/L)