Studies and full-scale test operations at Sacramento’s new Regional Treatment Plant site show that large-scale facultative sludge lagoons can be operated with minimal odor emissions and a lack of complaint or nuisance conditions. Source odor controls are being implemented at Sacramento as well as use of supplemental odor dispersion equipment and operational controls on the lagoons. Nuisance risk projections show that complaint conditions in nearby residential areas will be extremely rare. This innovative project has led other communities to re-examine the sludge lagoon for its potential usefulness. These sludge lagoons are now being used in areas of freezing winter conditions, and their potential for use in areas other than the Western United States seems likely.