If flow diversion is not an option or the TSS and particulate BOD removal with Actiflo alone are not enough, a biological solids contact tank, BioActiflo, can be incorporated into the treatment flow path to improve soluble BOD removal through the system. Return activated sludge from the existing clarifiers is combined with the excess flows into a solids contact tank. A targeted mixed liquor suspended solids concentration is maintained in the contact tank to facilitate rapid uptake of soluble BOD via contact stabilization. Clarification with Actiflo follows, producing TSS and total BOD removal rates that allow for efficient disinfection.