Free and total chlorine concentrations were determined by DPD (N,Ndiethyl-p-phenylenediamine) colorimetric method with a Pocket Colorimeter TM chlorine test kit (Hach Co., Loveland, Colo., U.S.A.).
Freeand total chlorine concentrations were determined by DPD (N,Ndiethyl-p-phenylenediamine) colorimetric method with a PocketColorimeterTMchlorine test kit (Hach Co., Loveland, Colo., U.S.A.).