Dried sewage sludge has been used as a fertilizer material for several decades in the United States. While sludge drying and fertilizer production is normally more costly than other municipal sludge options, in many situations it represents a feasible, cost-effective solution. New processes to dry sludge with less energy are being developed. However, there are several risks associated with sludge drying and reuse projects including technological risks, equipment reliability, market risks, and risks associated with future regulatory uncertainty.