The application of granular and biological activated carbon columns in removal of organochlorine and organophosphorus pesticides in a water treatment plant

Abstract

As it is not feasible to remove pesticides from water sources through conventional treatment methods, the utilization of supplementary treatment approaches, such as biological adsorption processes, becomes necessary. The present study investigated the performance of the biological and granular activated carbon in 18 organophosphate and organochlorine pesticides removal from raw water entering Shiraz city water treatment plant separately. The biosorption and granular activated carbon columns were placed after the ozonation unit. The results demonstrated that the activated carbon column effectively removed pesticides, including trans-chlorfenvinphos, fenthion, parathion, bromofos, and alachlor. Additionally, the biological activated carbon column exhibited a 100 % removal efficiency for trans-chlorfenvinphos, methyl parathion, malathion, bromofos, parathion, trifluralin, and alachlor. Biosorption efficiency in all pesticides was found to be greater than or almost equal to the removal rate by the adsorption process. As an example, the adsorption efficiencies for ethyl paraoxon, methyl parathion, and atrazine pesticides were 88.4 %, 67.38 %, and 64.67 %, respectively. Furthermore, the corresponding biosorption efficiencies were 94.45 %, 100 %, and 98.43 %, respectively. It can be concluded that there is a synergistic interaction between adsorption and biodegradation processes in biological activated carbon systems. Thus, the biological adsorption process can be employed as an efficient filter along with other conventional treatment processes in order to remove pesticides in urban water treatment plants.