Chemical precipilalion and flocculalion processes is \videly used in water treatment operations. in chemical precipitation processes, water treatment is provided by holding of colloidal partieles in precipitate. During this operation, a chemical used as flocculant can be added to waste water in order to get precipitation processes quickly. in addition to getting quick precipitation. precipitate with large partide size is oblained after the flocculation processes and this partieles can be removed casily by filıration. Whaıever the waste water have different characteristic, determination of the amount ol' chemical that wjll be used in treatment is needed to laboratory studies. in this study, a laboratory work which is carried out in order to remove the colloidal pollu-uint in waste water of gas stations and motor cleaning units is presented and a suitabk1 method that will be easy applicablc such as units is offered.