The Study On Treatment Of Pesticide Wastewater By Ultrasonic-electrocoagulation Process

With the increase of population and the decrease of cultivated land,grain problem has become an important factor restricting China's economic development.The use of pesticides has resulted in a significant increase in grain production per unit area,but at the same time brought many environmental problems.Which is particularly serious impact on the water environment,so how simple and efficient treatment of pesticide wastewater has become a hot topic of concern in today's society.Based on the situation of the advantages and disadvantages of various processes at home and abroad,this paper combined Electrocoagulation and Ultrosonic method to treat pesticide wastewater,and explored to determine the optimum operating conditions of each unit.In the experiment of electrocoagulation process treatment,the electrolysis time,electrolysis current and electrode spacing are investigated by orthogonal experiment.The order of three factors to treatment efficiency was electrolysis time>electrolysis current>electrode spacing.The optimum operating conditions of the wastewater were:electrolysis time was 60 minute,electrode spacing was 3 cm,and the current density was 20mA/cm2.Under this condition,the removal rates of CODCr,TOC and chroma were 37.01%,22.89%and 51.16%.The degradation of CODcr was described by the second-order reaction kinetics.In the research of ultrasonic process treatment,ultrasonic time,ultrasonic power,pH value were investigated by orthogonal experiment.The order of three factors to treatment efficiency was ultrasonic power>ultrasonic time>pH value.Under the condition that ultrasonic time was 60minute,ultrasonic power was 200W and pH was 4,the removal rates of CODCr,TOC and chroma reach 16.42%,11.33%and 19.22%,respectively.The degradation of CODCr was described by the first-order reaction kinetics.In addition,reducing the pH of the wastewater will improve the treatment efficiency.In the study of Ultrasonic-Electrocoagulation combination process treatment,using the sectional method and combined treatment,the experiment results combined treatment was more better.When combined treatment 70 minute the removal rates of CODCr,TOC and chroma were 65.20%,43.13%,70.65%,respectively.Compared to electrocoagulation and ultrasonic,the effect has been greatly improved.It was more efficiency than using Electrocoagulation and Ultrasonic separately.The kinetic process of Ultrasonic-Electrocoagulation degradation was described by the first-order reaction kinetics.