The electrocoagulation technique is applied for the treatment of hazardous cephalothin sodium antibiotic wastewater. The interaction effects of the various parameters on the maximization of removal efficiency and minimization of energy consumption are evaluated through multivariable optimization. The disposal of sludge is effectively performed by soil stabilization. Scanning electron microscopy analysis of soil fused with sludge shows an ordered arrangement with reduced void space. The improvement of soil properties is confirmed by the change in soil expansiveness from low to moderate region and by an increase in compressive strength. © 2021 Wiley-VCH GmbH