Methods and systems for reducing a redox active contaminant in a waste stream in a waste treatment system involve performing a unit process of the waste treatment system by contacting redox active contaminant in the waste stream with oxyhydrogen-rich gas generated on-site by an oxyhydrogen gas generator that implements water dissociation technology. The oxyhydrogen gas generator involves applying a pulsed electrical signal to a series of closely spaced electrodes that are submerged in the waste stream to produce oxyhydrogen-rich gas from a water component of the waste stream. Operation of the oxyhydrogen gas generator in the waste stream may accomplish one or more unit processes for waste treatment, such as oxidation, stripping, floatation, disinfection, conditioning, stabilization, thickening, and dewatering, among others.