Development of granulated activated carbon using Corner Brook pulp and paper mill fly ash for drinking water treatment

Abstract

Natural organic matters (NOM) interact with disinfectants and produce disinfection by-products (DBPs). One of the best available technologies to remove NOM from water to reduce DBPs formation is adsorption with activated carbon. In this study, the removal of NOM from pond water was studied using powder activated carbon (PAC), and the granular activated carbon (GAC) generated from Corner Brook Pulp and Paper (CBPP) fly ash as raw material. PAC was used in batch tests and water pH, temperature, and volume was considered as variables to determine optimized conditions for NOM removal applying response surface method (RSM); it was concluded that water pH and volume have significant effects on NOM removal. CBPP was combined with bitumen as a binder to produce GAC. Effect of binder to carbon ratio, calcination and steam activation temperature, the temperature increasing rate, and steam activation time were studied to produce GAC with high BET surface area and efficient hardness. Granules with 30:70 binder to carbon ratio, calcinated at 750°C, activated at 950°C for 3 hours with 15°C/min of heating rate were found to be ideal for GAC production for NOM removal. Column tests for NOM removal were conducted using produced GAC. Results indicate that the produced GAC is effective for 60% NOM removal. Follow-up chlorination experiments illustrate that the formation of DBPs (THMs and HAAs) were significantly reduced. Used GAC was regenerated using RSM design at different regeneration temperature, time, and steam flow. The results show that regeneration at 916°C for 43 minutes under 350 mL/min of steam would lead to optimum regeneration conditions.