In order to neutralize the wastewater sample, various dosages of CaCO3 then were added into the samples and their pH was measured. Fig. 1b shows pH values of the samples added by various dosages of CaCO3. Along with the increasing of CaCO3 dosage the pH value of the wastewater samples increased. The addition of more than 5 g CaCO3 resulted in insignificant increase of pH value. Furthermore, addition of higher CaCO3 dosage to the samples may also raise suspended solid in the samples. Due to these reasons, dosage of 5 g CaCo3 was used in this study.