Determination and speciation of selenium in end products from a garbage incinerator

Flyash, flue gas cooler condensate, and sludge from the refuse incinerator in Uppsala, Sweden, were analyzed to determine the concentration and oxidation state of selenium. Se concentrations in these end-products were studied during a two-week period, and the approximate flow of Se in the gas purification system was calculated. The element is present almost exclusively as Se(IV); a minor fraction exists as Se(VI). Se is present solely in the (IV) form in flyash and in the primary condensate. This shows that the element is present in the flue gas as gaseous selenium dioxide, since no redox reactions should occur when Se is washed out of the gaseous phase.