AWWA MTC61215

The radically different fouling rates between nanofiltration and reverse osmosis (NF/RO) processes treating groundwater and surface water with similar organic and inorganic content are well documented. This paper explores the hypothesis that the presence of the electron acceptor dissolved oxygen (DO) is primarily responsible for higher fouling under aerobic feedwater conditions. Through the use of productivity and water quality monitoring, biofilm characterizations, bench-scale testing, and semi-empirical membrane productivity modeling, this paper presents observed fouling experiences at two membrane facilities, both located in Florida: City of Dunedin Membrane Softening Water Treatment Plant; and, City of Ft. Myers' Eddie D. Edwards Water Treatment Plant. The Dunedin case study presents information gathered as part of a forensic microbiological plant profiling investigation, whereas the Ft. Myers case history includes a full-scale plant performance and bench-scale fouling evaluation. Includes 11 references, tables, figures.