Alum Stormwater Treatment Services
In the late 1970s, Dr. Harvey H. Harper, P.E., while a faculty member in the Department of Civil and Environmental Engineering at the University of Central Florida, began testing the effectiveness of liquid aluminum sulfate (alum) and other coagulants to remove pollutants, nutrients, heavy metals, and bacteria from stormwater runoff. This testing yielded very favorable results, and in the 1980s, alum treatment of stormwater runoff was evaluated for several stormwater retrofit projects, with the initial system constructed in 1987 at Lake Ella by the City of Tallahassee.
Prior to design, a preliminary evaluation phase was conducted which included extensive alum jar testing with stormwater runoff and chemical analysis of raw and alum treated stormwater. Once the system was operational, FDEP funded a 2-year study to evaluate the affect of alum treated stormwater runoff on lake water quality, lake sediments, and benthic activity. This study also evaluated the stability and accumulation rate of the alum floc. The extensive study on Lake Ella yielded extremely favorable results in all areas evaluated.
ERD has designed, permitted, and administered construction on more than 50 alum stormwater treatment systems, reflecting more than 90% of the existing systems world-wide. During 2008, construction was completed on the Lake County Nutrient Reduction Facility (NuRF) which has a treatment capacity of 300 cfs and is the largest system in existence. The system includes two floc storage ponds, a dedicated dredging system, floc dewatering system including centrifuge, and a floc storage area.