The combined UV/chlorine process

as a photochemistry process

was investigated to improve the removal efficiency of ammonia in drinking water. Based on a central composite design

the effects of Cl/N mass ratio

UV radiation time and pH value and their combination on the ammonia removal rate were evaluated. Based on a mathematical model established between them

and these technical parameters for the combined UV/chlorine process was optimized. The results showed that all of the three factors had significant impacts on ammonia removal and the combined influence of Cl/N mass ratio and UV radiation time was also outstanding. Furthermore

the prediction of a second-order regression model (R2=0.992) derived by response surface methodology was satisfactory. The conditions obtained by optimization to meet the standard of ammonia concentration in drinking water (0.5 mg·L-1) were: Cl/N mass ratio 4.00

UV radiation time 6.00 min and pH value 7.5. The experimental value agreed with the predicted value with only 0.64% deviation. Finally

these results illustrated that combined UV/chlorine process was an effectively alternative method for ammonia-containing water treatments

with several advantages of low chemical consumption

high efficiency and easy operation.