Your situation helps -- small flow and ca. 60% COD removal. This can probably be done using Fenton's Reagent (iron-catalyzed H2O2) in a batch treatment process. The process is described at http://www.h2o2.com/pages.aspx?pid=143&name=General-Chemistry-of-Fenton-s-Reagent and its use for BOD/COD...
Before creating these mixtures, please take time to learn about ternary mixtures of H2O2-organic-water and their detonability. I've uploaded the diagram for the mix H2O2-EtOH-water for your review...
Though totally miscible with water, 50% H2O2 is 20% heavier than water. Diluting the H2O2 'inline' with carrier water (to e.g., 1-2% or less) will help its mixing, as will using one or more pressure injectors to shoot the diluted solution into the center of the flow (as opposed to letting 50%...
It's most likely sodium carbonate peroxyhydrate (http://www.solvaychemicals.us/services/resourcelibrary/sodiumpercarbonate/0,,40488-2-0,00.htm)
or possibly calcium peroxide (http://envsolutions.fmc.com/PermeOxPlus/tabid/360/Default.aspx) or magnesium peroxide...