Abstract: A chlorine dioxide generation system includes a process water passage formed in an integral structure proximate a first end of the integral structure. A chlorine dioxide reactor is formed in a bore of the integral structure and coupled to the process water passage. A precursor passage is formed in the integral structure proximate a second end opposite from the first end. The precursor passage has a first opening opposite a second opening coupled upstream of the chlorine dioxide reactor. First and second inlets are coupled to the precursor passage at the first and second end respectively. First and second backpressure valves are coupled to the first and second inlets respectively. First and second precursor pumps are coupled to the first and second backpressure valves respectively. A first precursor is coupled to the first precursor pump. A second precursor is coupled to the second precursor pump.