Water Systems for Pharmaceutical Facilities 597 Since chlorine is removed from water by the carbon, extra care is quired from here on to protect against bioburden growth. Carbon bed themselves are good breeding grounds for bacteria. To keep the system in check, a recirculation system as depicted in Fig 3 is recommended. The constant recirculation avoids water stagnation and reduces viable bioburden Figure 3. Activated Carbon Activated carbon is manufactured by heating selected or other higher carbonaceous material in the absence of ctivation"process burns out impurities and produces a honeycomb-like structure containing millions of tiny pores. The structure provides a large total surface area that enables the carbon to adsorb(attract and hold to the surface)large quantities of contaminants. Chlorine, or its related elements are first adsorbed on the surface of the pores where they react with the carbon to liberate chloride. Because of this reaction and deterioration of chlorine the capacity of activated carbon for chlorine removal is exceedingly high. In addition to chlorine removal and adsorption oforganics, the granular carbon is an effective filter. Although removal of turbidity will shorten the carbon life by blocking pores, the carbon will function as an excellent filter. Particle removal down to 40 microns can be achieved with freshly backwashed bedsWater Systems for Pharmaceutical Facilities 59 7 Since chlorine is removed from water by the carbon, extra care is required from here on to protect against bioburden growth. Carbon beds themselves are good breeding grounds for bacteria. To keep the system in check, a recirculation system as depicted in Fig. 3 is recommended. The constant recirculation avoids water stagnation and reduces viable bioburden growth. Filtered Water 5 Mlcron Fllter 0 I Drain Figure 3. Activated Carbon. Activated carbon is manufactured by heating selected grades of coal or other higher carbonaceous material in the absence of oxygen. This “activation” process burns out impurities and produces a honeycomb-like structure containing millions of tiny pores. The structure provides a large total surface area that enables the carbon to adsorb (attract and hold to the surface) large quantities of contaminants. Chlorine, or its related elements, are first adsorbed on the surface of the pores where they react with the carbon to liberate chloride. Because ofthis reaction and deterioration of chlorine, the capacity of activated carbon for chlorine removal is exceedingly high. In addition to chlorine removal and adsorption of organics, the granular carbon is an effective filter. Although removal of turbidity will shorten the carbon life by blocking pores, the carbon will function as an excellent filter. Particle removal down to 40 microns can be achieved with freshly backwashed beds of carbon