One must consider the control of biological activity when designing a water system. Continuous sanitization is achieved in any part of the system where the water remains chlorinated or is maintained at a temperature exceeding 165 degrees F. For the typical system described above, all components upstream of the point of dechlorination are continuously sanitized by the chlorinated water. The distillation unit will not have any biological activity as the water is heated to a sufficient temperature.
Therefore, in a typical system, the potential area for biological activity in the equipment is between the point of dechlorination and the distillation unit, namely the carbon filter, polishing softener and interconnecting piping. The biological activity in this area is controlled by periodic sanitization.
This periodic sanitization can be accomplished in several ways including:
Portions of the system can be chemically sanitized with a recirculating biocide as indicated in the diagram.
The equipment needed for chemical sanitization includes a recirculation pump, biocide reservoir and associated piping and/or hoses. Electrical power to the pump would be required. These chemical sanitization systems are generally separate from the water system and are moved into place and connected when sanitization is needed.
Portions of the system can also be thermally sanitized with either hot water or steam.
Hot Water Sanitization
The equipment needed for hot water sanitization includes a recirculation pump, expansion tank, heat exchanger and associated piping. Steam and condensate piping to the heat exchanger and electrical power to the pump would be required.
These hot water sanitization systems are generally integral to the water system and are isolated by valves until sanitization is needed.
The equipment needed for steam sanitization includes a source of pure steam, generally from a pure steam generator, and associated piping. These steam sanitization systems are generally integral to the water system and are isolated by valves until sanitization is needed.
The pure steam generator may be a central unit used for a variety of pure steam requirements in the facility or it may be a dedicated unit for the water system sterilization. Steam and condensate piping to the heat exchanger and electrical power to the pure steam generator would also be required.
MECO MASTERedge™ Sanitization
The main component of a pharmaceutical water system is the distillation unit. All of the upstream equipment serves to pretreat the water before it enters the distillation unit. The downstream equipment stores and distributes the distillate produced by the distillation unit.
Distillation units for pharmaceutical water systems utilize either the multiple effect distillation process or the vapor compression distillation process. The distillation unit shown here utilizes the vapor compression process.
The specific area of interest with respect to the sanitization is shaded in the diagram on the right. During normal (distillate production) operation or standby operation the shaded area contains pure steam at 1 to 4.5 psig.
The steam is produced by the addition of heat by the feed heater and from heat given up by condensation. The important issue is that a source of pure steam, suitable for sanitization, is available from the still without the addition of additional equipment.
The MECO MASTERedge™ Sanitization process utilizes the pure steam available from the distillation unit for sanitization of the upstream components. This arrangement eliminates the need for a dedicated pure generator or the need to pipe pure steam from a central pure steam generator.
The controls needed to automate the sanitization procedure can be incorporated into the system without involving outside equipment. A properly designed system allows sanitization while the distillation unit is in the standby or normal operating modes.