Paper Title
Effects of Metal Ions (CU, ZN, PB, MN, And NI) on Water Quality of Campus Wastewater Applying Backward Stepwise Multiple Linear Regression

Abstract
The study is related to the application of backward stepwise MLR (multiple linear regression) method to assess the effect of given metal ions (Cu, Zn, Pb, Mn, and Ni) on water quality parameters (BOD, COD, TSS, and pH) in campus wastewater of interest. The results show that all given metal ions give no significant effect on BOD (biological oxygen demand), COD (chemical oxygen demand), and TSS (total suspended solid) except on pH regardless its sampling site and time. Internal interactions are found related to Mn remarkable character over other given metals shown by the backward stepwise MLR method. Transition metal and amphoteric characters of those metal ions and their effects on given water parameters (BOD, COD, TSS, and pH) have been discussed concerned with possible internal interactions among those metal ions in water. This study shows that backward stepwise MLR method is useful as an aid to discuss water quality cases. Keywords- Backward Stepwise Mlr, Metal Ions, Campus Wastewater, Water Quality Parameter.