Ferric chloride plus GAC for removing TOC

Granular activated carbon (GAC) treatment is one method that water utilitie s can use to increase removal of natural organic matter and comply with the recently promulgated Disinfectants/Disinfection By-products Rule. The cost of GAC depends on its useful service life and its capacity for reuse. The research reported here used minicolumns to investigate how ferric chloride coagulation influenced the total organic carbon (TOC) subsequently removed by GAC. Ferric chloride pretreatment lengthened GAC bed life by lowering in fluent TOC and by rendering the TOC that remained more adsorbable. Jar test s showed that at pH<6.0, ferric chloride was superior to aluminium salts, o n an equimolar basis, for removing TOC.