A system and process for removing from an aqueous stream impurities such as grit, particulates, floating debris, suspended solids, turbidity, bacteria, fecal coliform, oil, grease, color, and the like, and for treating an unacceptable biological oxygen demand, chemical oxygen demand, and/or dissolved oxygen by utilizing a treatment system positioned partially in a channel adapted to a flow of the aqueous stream. The treatment system comprises a containment zone for containing the aqueous stream for treatment by at least one of traveling or stationary screen filtration, aeration, anaerobic and/or aerobic digestion, clarification, media filtration, chemical addition, disinfection, pH adjustment, particulate removal, and/or the like. A partition wall is provided to bypass untreated water such as storm water. After passing untreated waste water through the treatment zone, the treated aqueous stream may be recycled for further use or discharged to its desired destination, such as a lake, river, or ocean.
