Application of Physical and Biological Treatment Methods to Purify Diazinon and Malathion Pesticides in Water

The present study was aimed to remove the organophosphorus pesticides diazinon and malathion from artificial water body using clay particles and activated carbon as the absorbents in a bit-trap system, and algae absorbent in a bio-treatment system. Physical treatment system, the bit-trap system, contained two separate but related tanks with sheath media to tap extra materials; and also received specific amount of montmorillonite clay and activated carbon in daily schedule. Bio-treatment system was also equipped with Cyanophyceae species. microalgae on the sheath media. Pesticides in two different concentrations (10 and 1000 mg/L in physical, and 6 and 60 mg/L n biological systems) were added to the treatment system. Study duration was 10 days, and daily water sampling was conducted to evaluate concentration of the pesticides and pH. Results showed that physical treatment system was successful to remove the pesticides with the reduction efficacy of 64% and 48%, and 68/7% and 41/3% for 10 and 1000 mg/L diazinon and malathion, respectively. After 10 days, bio-treatment system was also reduced the amount of pesticides with the 68/3% and 71/6%, and 40/5% and 67/8% for 6 and 600 mg/L diazinon and malathion, respectively. In the both treatment systems, pH was gradually increased along with the removal of pesticides. These results represent the efficacy of bit-trap system as a suitable medium for the absorbents which removed the major amount of pollutants. Also, the results of this study provide a reliable backbone of the role of micro-algae in water treatment from pesticides.