Oil field operation waste liquid treatment system and method

The invention discloses an oil field operation waste liquid treatment system. The system comprises an oil-water separation unit, an ultrasonic treatment unit, an air oxidation unit, a static mixing unit and a three-phase separation unit which are connected in sequence. The invention also provides an oil field operation waste liquid treatment method, which comprises the following steps: leading out wellhead operation waste liquid under pressure, separating oil from the operation waste liquid, adding a neutralizer into the operation waste liquid after oil separation, and carrying out ultrasonic treatment to realize chain scission of the residual macromolecular organic additive; the method comprises the following steps: carrying out ultrasonic treatment on the operation waste liquid, introducing air into the operation waste liquid subjected to ultrasonic treatment, oxidizing the operation waste liquid by oxygen in the air, adding a coagulant and a flocculant into the operation waste liquid subjected to air oxida