The performance of highly doped SnO, anodes for the oxidative treatment of biologically refractory
~aste water was compared with PbO, and Pt. The oxidation of a wide range of organic compounds
proceeds with an efficiency which is about 5 times higher than with platinum anodes. The oxidation
efficiency was found to be independent of the pH of the wgter. In chloride containing media, SnO,
anodes produce less chlorine gas than platinum anodes and hence show less potential to form
hazardous chlorinated organic by-products. The design of a simple plate-and-frame reactor with
undivided cells for waste water treatment using SnO, anodes was based on two experimental findings:
(a) no interference of the cathode with the oxidation has been found: (b) the rate of oxidation is not
limited by tnass transfer, indicating the participation of homogeneous reactions in the overall oxi-
dation. The new anode material reduces the specific energy requirement of electrochemical oxidation
of organics in waste water to 30 to 50 kWh kg -' of COD removed. This makes the process an
interesting alternative to chemical oxidation using oxidants such as ozone and hydrogen peroxide, or
let oxidation using oxygen at elevated temperature and pressure.