Study On The Treatment Of Paper Mill Wastewater By Ultrasound

Nowadays ultrasound has been successfully used to degrade the organic pollutants in wastewater , meanwhile many water treatment experts have paid more attention to study the ultrasonic irradiation technology. Ultrasound is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other treatment methods. In this paper the recent studies on the degradation of organic pollutants by ultrasound and associated degradation mechanism for the treatment of paper mill wastewater were reviewed. And the researches on the technologies of ultrasonic irradiation,ultrasound/hydrogen-peroxide,ultrasound/Fenton were used to degrade different paper mill wastewater. The factors, such as ultrasonic frequency,power intensity,duration time,different COD,dissolved gas,coexistent ion and ?OH radical scavenger affect the efficiency of degradation were investigated. Results show as follows:When treated by ultrasound, the destruction of organic compound in paper wastewater is effective.Reaction time affects the degradation of paper wastewater. US-H2O2/US-Fenton are both better than ultrasonic irradiation alone.Acoustic power and ultrasonic frequency are both important factors of the degradation of paper mill wastewater ultrasound. Aerating gas to the black liquor increase the effect of ultrasonic cavitation, the order of degradation rate of different saturated gas is as follow: O2>Air>N2>degassed. Adding appropriate quantity of NaCl affect the degradation efficiency of black liquor.