IMPROVING GAC PERFORMANCE BY OPTIMIZED COAGULATION

The effect of optimized coagulation on granular activated carbon (GAC) performance for removal of natural organic matter and control of disi nfection by-products was investigated. Coagulation optimized for total organic carbon (TOC) removal increased GAC run times by a factor of 2 -3 over run times observed for GAC receiving conventionally treated wa ter. The improved performance was mainly a result of reductions in inf luent TOC and pH after optimized coagulation, as compared with convent ional pretreatment. Conventional coagulation prior to GAC was more cos t-effective than optimized coagulation, because of increased costs ass ociated with the high alum dosages used in this study.