An apparatus, system and method for clarifying wastewater using electrocoagulation with plasma discharge is provided. The apparatus includes a reactor with a hollow interior accommodating a volume of wastewater for treatment, and electrodes contacting or at least partially submerged in the wastewater. Electrical energy is supplied to the electrodes, such as three-phase AC power, of sufficient levels to generate plasma discharge from the electrodes and within the wastewater. Electrocoagulation occurs concurrent with the plasma discharge. A system including at least one reactor is a flow-through system, and may have a recirculation loop for recirculating wastewater for additional passes of treatment. A pump(s) and series of valves control the movement of wastewater through the system, and a control panel may be included to direct the operation of various components of the system. The control panel may also include a user interface for information display, input by an operator, and automation.