Thiocyanate ions can be removed from sodium carbonate/bicarbonate solution that is used for oxidative scrubbing of H2S using a moderately basic anion exchange resin (see US 4,999,113). The flow rate of the scrubbing solution is 40 m3 /h and the initial concentration of thiocyanate is 10 g/l. A polystyrene-based anion exchange resin suitable for this duty has capacity of 1.8 eq/L. The resin can be regenerated by flushing 1.5 equivalents of 4.0 wt% NaOH, preceded by the same volume of water. Two beds are used, with one in operation and one in regeneration. If the bed is designed to be 80% loaded at the end of a 2 hour operation cycle, estimate the bed volume. Also determine the flow rate of sodium hydroxide required during the regeneration.