Iron salts are effective in controlling sulfide odors produced by sludge blanket samples of a facultative waste treatment lagoon receiving concentrated sulfite waste from a pulp and paper manufacturing facility. Complex interactions between dissolved iron species and reduced sulfides interfere with predictions of effective chemical dosing, requiring site/season-specific dose determinations. For example, samples collected during periods of warmer weather, when metabolic rates are higher in the sludge blanket, require higher dosages of ferric chloride for odor control. A technique is presented that uses jar tests to determine effective dosage rates of iron salts to produce a desired odor-free period in a particular waste. Potentially, large volumes of sludge may be generated through the possible precipitation of metal–sulfide complexes. Iron-rich waste products may provide a cost effective source of ferric iron for these applications. Key words: Wastewater; pulp and paper wastes; reduced sulfides; odor control; iron salts; chemical requirements