CITRONELLE, ALABAMA

With over 2400 kms (1500 miles) of inland waterways, Alabama has one of the highest percentages of water among all US states. With this knowledge in mind, it is in Alabama communities like Citronelle, who have the potential to experience both the far-reaching effects of phosphorus and where changes made to reduce discharged phosphorus could see the greatest long-term impact.

With phosphorus-fed algae blooms plaguing many North American bodies of water, and in response to environmental concerns, regulators are pressuring wastewater treatment plants (WWTP) to meet ever decreasing phosphorus limits. These limits vary, but are usually tied to Total Maximum Daily Loads (TMDL) established for bodies of water. In regions where permits have addressed phosphorus pollution, discharge limits traditionally range from 1 mg/L down to 0.1 mg/L total phosphorus (TP). However, as populations shift around waters with established TMDLs, targeted treatment levels for phosphorus are driven lower.

A 0.1 mg/L limit has historically been considered an ultra-low target. But in Citronelle, they faced an even steeper challenge from regulators with a new ultra-low phosphorus target of < 0.02 mg/L, which is among the lowest requirements in North America.