The County of Maui, Hawaii, operates three wastewater reclamation facilities (WWRF) on the island of Maui: Kihei WWRF, Lahaina WWRF, and Wailuku-Kahului WWRF. All three facilities are similar in terms of influent loading, absence of primary treatment, use of anoxic/anaerobic zones, and relatively constant year-round temperatures. As a result of expansions that combined the use of existing and new tanks during the past 10 years, the secondary processes at each facility differ. These differences include the size and flexibility of the anoxic/anaerobic zones and the means of nitrate recycle (RAS versus MLSS). Despite these differences, significant nitrogen and phosphorus removal is being achieved, as shown in the table below, even though little optimization of nutrient removal has been attempted.