Study on Dissolved Ozone Flotation Treatment of Gas Field Produced Water

The DOF process was selected for the treatment of a gas field in northern Shaanxi with complex water quality and high mineralization, and experimental studies were conducted to analyze the wastewater quality, optimize the chemical formulation and analyze the sludge dewatering performance. The results show that the fractal dimension is smaller and the treatment effect is best when the NaOH dosage is between 540 mg·L−1 and 900 mg·L−1, the ozone gas flotation gas–water ratio is 1:6 and the PAM dosage is 2.5 mg·L−1. The maximum removal rates of SS, oil and total iron are 85.71%, 84.77% and 92.01% respectively, which indicates that the DOF process has good treatment effect on the gas field produced water. The sludge dewatering rate was 92.18% and the dewatering capacity was 84.99 kg·(m2·h)−1, which indicated that the sludge dewatering performance was good and it was easy for the subsequent sludge reduction treatment.