Investigating the Efficiency of Enhanced Coagulation Process for the Removal of Humic Substances from Water

Humic acids are main components of natural organic matters that have many negative effects, especially reaction with chlorine and production of disinfection by-products in water. Thus, the methods for the removal of these substances from water have been considered. Enhanced coagulation is a simple, suitable and efficient process for the removal of humic substances.
This study evaluates the enhanced coagulation effectiveness, as a suitable method for the removal of humic substance by polyaluminium chloride as a coagulant in a concentration between 1 to 20 mg/l in jar test.
Dissolved organic carbon, ultraviolet absorbance, specific ultraviolet absorbance and humic acid were determined as humic substances indexes in concentration between 0.1 to 5 mg/l. According to the obtained results, high level of specific ultraviolet absorbance index in the water source showed that enhanced coagulation was necessary for the removal of humic substance. Also, according to the obtained results, the average removal efficiency obtained by enhanced coagulation for humic acid was 52%, for dissolved organic carbon was 43% and for UV254 was 57%.
It was concluded that employing polyaluminium as a coagulant in enhanced coagulation process is inexpensive, suitable and efficient and can remove humic substance to optimum value without decreasing turbidity efficiency.