An apparatus for providing metal ions to a fluid waste stream includes a housing having an inlet port and an outlet port through which the fluid waste stream enters and exits the housing. Within the housing and between the inlet and outlet ports is an electrode assembly that includes first electrode ring assemblies and second electrode ring assemblies. Each first electrode ring assembly includes a first tubular section formed of electrically insulative material and has an interior through which the fluid waste stream flows. One or more first electrode plates span the interior of the first tubular section and contact the fluid waste stream. Each second electrode ring assembly includes a second tubular section formed of electrically insulative material and has an interior through which the fluid waste stream flows. One or more second electrode plates span the interior of the second tubular section and contact the fluid waste stream. The first tubular sections of the first electrode ring assemblies are in fluid communication with the second tubular sections of the second electrode ring assemblies.