Removal of Butachlor Toxin Polluted Water Using Ozonation, A Case Study of Groundwater Resources in Guilan Province

Rice is an important staple food in most parts of the world. The water resources in Guilan Province are receiving large quantities of herbicides (butachlor) due to the vast rice fields in the province and the indiscriminate use of chemical fertilizers for increased harvest. The present study investigates the effects of ozone used for removing the remaining butachlor from groundwater. Samples were collected from 20 wells during four seasons and their physicochemical parameters were analyzed using gas chromatography and liquid extraction after their fixation. Quantitative measurements were performed using the standard enhancement method and removal methods were evaluated using an ozone generator. The results were subjected to statistical analysis using the SPSS software. The results showed that the residual concentration of butachlor in the samples was not above the recommended international limits. The effects of temperature, hardness, and pH were investigated to determine the efficiency of the removal method used and it was found that the butachlor removal efficiency of ozonation was higher in waters with an alkaline pH and high temperatures, while it decreased with increasing hardness. The pseudo-first order kinetic model was used to investigate the rate of ozone to butachlor contact to find that the product of ozone concentration by contact time had a linear and indirect relationship with the logarithm of the butachlor content.