The cost for odor control for the collection and treatment of municipal and industrial wastewaters has increased over recent decades. The implementation costs for odor control at a water recovery facility (WRF), typically only a few percent of the facility’s total build cost 20 years ago, is now sometimes close to 10% or more. The increase of these cost is driven by several relatively recent changes. Firstly, tighter controls of the waste, including metal waste which previously largely precipitated with odorous compounds. Secondly, water restrictions and innovations in water saving devices has resulted in an increase in the pollutant concentration in the sewer leading to increased septicity when entering the WRFs. Thirdly, there is a growing trend towards more centralized WRFs in many large cities, especially with the amalgamation of water authorities into larger utilities. In addition, there is often new community growth near the facilities. At the same time, many of these water utilities are seeing cost reduction demands driven by this same community to keep rates low.