AWWA MTC53865

Integrated water treatment with softening and ultrafiltration is proposed as apromising option for hard waters as a means to meet the changes in the recentregulations: the Disinfection/Disinfectant Byproduct Rule and the InterimEnhanced Surface Water Treatment Rule. Although ultrafiltration can accomplishexcellent disinfection by removal of microorganisms and some removal of naturalorganic matter (NOM) to meet the regulations prior to disinfection, fouling ofultrafiltration is the biggest impediment for applying membrane processes.Fouling leads to reduced flux or excessive pressure through the membranes andnecessitates building larger plants or excessive backwash that reduces thepercent recovery of the water. Therefore, pretreatment to reduce foulants fromthe feed is valuable. Previous research has examined the use of conventionaltreatment processes, particularly coagulation, as pretreatment, however,softening pretreatment has received virtually no research attention to date. Theobjective of this research is to understand the nature of the fouling mechanismsfor ultrafiltration when used for waters that either require softening or havebeen softened. With that understanding of fouling mechanisms, one can determinewhether softening is a reasonable option for a pretreatment beforeultrafiltration. Therefore, to investigate the feasibility of a softening processas pretreatment of ultrafiltration, several independent variables are beinginvestigated for their effects on process performance in this research. At thistime, only some of the initial work has been completed and is reported herein. Includes 12 references, tables, figures.