Abstract

There are number of issues in soft drink industries’ mode of GAC operation, however, this study focuses on three issues like control of regeneration breakthrough in line with Chlorine and THM breakthrough; its frequency of regeneration and finally the competitive adsorption of different THM on two different types of GAC and extrapolation of result to full scale plant. All the experiments were conducted using rapid small scale column test (RSSCT). And for de-chlorination experiment, deionized water spiked with 2 mg/L chlorine (HOCl) was used. On the other hand, for THM’s removal experiment, deionized model water was used with two THM species (chloroform, bromoform or mixture of both components) at a total THM concentration of approximately 80 µg/L. In the experiments, GAC breakthrough curves were established with RSSCT protocol. Therefore, in this study, GAC regeneration is reveled to be controlled by THMs removal. And, RSSCT suggests that in the treatment plant (THMs concentration in feed water of approximately 80 µg/L) Calgon F200 GAC (empty bed contact time (EBCT) = 7.12 min) could treat up to 12000BV before breakthrough of 10 µg/L and this would correspond to 2 months operation. In this study, both Calgon F200 and Norit GCN 1240 also demonstrated in RSSCT experiments that THMs can be effectively reduced below 10 µg/L. However, RSSCT-chloroform adsorption showed slightly higher capacity of Norit GCN 1240 at lower concentration (< 40 µg/L) and slightly higher capacity of Calgon F200 at higher concentration (> 50 µg/L) for Co= 79.8 ± 4.30 µg chloroform/L and EBCT of 0.31 min.

Key words: Granular activated carbon (GAC), rapid small scale column test (RSSCT), bromoform, chloroform, de-chlorination and trihalomethanes (THMs).