COMPARISON OF COD AND TSS REMOVALS FROM ARTIFICIAL RIVER WATER BY MUDBALLS MADE WITH ACTIVATED EM1 AND EM4 SOLUTIONS

Abstract

In Indonesia, surface waters are often polluted by domestic waste. The use of Effective Microorganisms (EM) mixed with rice bran and clay soil then shaped into mudballs has been suggested as a means to directly improve water quality of polluted rivers. This study examined the removal of COD and TSS by 2.5 cm f mudballs made with two different kinds of activated EM solutions, i.e. EM1 and EM4.  Batch experiments at 30°C were conducted where artificial river water was treated with mudballs made from rice bran, and clay soil, which was mixed with either activated EM1 or EM4 solutions. Removal efficiencies of 120 mg/L COD by the mudballs were respectively 60.3% with EM1 and 59.4% with EM4.  Removal efficiencies of 100 mg/L TSS were respectively 100% with EM1 and 97.9% with EM4. Statistical hypothetical testing of the experimental data suggests that at a=0.05, there is no difference in removal efficiencies of COD and TSS by mudballs made with either EM1 or EM4. COD and TSS removal efficiencies are correlated with mudballs’ diameter; where increasing diameter results in better removal efficiencies. pH values of artificial river water after 5 days treatment by mudballs mixed with EM1 and EM4 were respectively 6.2 and 4.8.  TSS isotherm sorption by mudballs with EM1 better fits the BET model, with q_m= 32.4 mg/g, whereas that with EM4 better fits the Langmuir model, with Q_m = 7.52 mg/g; K_L = 0.0168 L/mg and R_L = 0.373. It appears that EM1 would be the preferred EM solution for direct treatment of polluted surface waters.