The factors that affect trihalomethane (THM) (chloroform, bromodichloromethane, chlorodibromomethane and bromoform) formation from
the chlorination of aqueous solutions of hydrophobic fulvic acids (FA) were investigated in a prototype laboratorial simulation using factorial
analysis. This strategy involved a fractional factorial design (16 plus 5 center experiments) of five factors (fulvic acids concentration, chlorine dose,
temperature, pH and bromide concentration) and a Box Behnken design (12 plus 3 center experiments) for the detailed analysis of three factors (FA
concentration, chlorine dose and temperature). The concentration ofTHMwas determined by headspace analysis by GC–ECD. The most significant
factors that affect the four THM productions were the following: chloroform—FA concentration and temperature; bromodichloromethane—FA
concentration and chlorine dose; chlorodibromomethane—chlorine dose; and, bromoform—chlorine dose and bromide concentration. Moreover,
linear models were obtained for the four THM concentrations in the disinfection solution as function of the FA concentration, chlorine dose and
temperature, and it was observed that the complexity of the models (number of significant factors and interactions) increased with increasing
bromine atoms in the THM. Also, this study shows that reducing the FA concentration the relative amount of bromated THM increases
