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in the water are defined and controlled. In most pharmaceutical facilities
municipally supplied drinking water is used as the raw material. In a few
facilities local borehole water, or sometimes river water, is used as the starting
material but this must be monitored and tested to show it meets the standards
required for drinking water.

3.5.3 Volumes and quality of aqueous process and waste streams
Within a pharmaceutical facility there are a wide range of process-related
aqueous effluent streams. Firstly there are effluent streams from the water
purification process itself. Since these mostly contain the concentrated
impurities present in the drinking water supply it is unlikely that such
streams would be suitable for recycling within the water treatment system since
this would led to accumulation of impurities, but they may be employed in other
site applications. The typical waste streams are back-washings from
regeneration cycles on multimedia filters, organic scavengers and water
softeners. In a pharmaceutical water system it is common practice to remove
hardness from the water by passing the feed water through a cation resin
exchanger in the sodium form to exchange hardness ions (calcium and
magnesium) with sodium. Consequently, the RO reject water will normally be
softened filtered water with a conductivity up to four times that of the potable
mains feed. Depending on the feedwater conductivity this water may be suitable
for use for similar applications as those of recovered grey water, although it
cannot be reclaimed within the water treatment system.
Water that may be suitable for recycling within the water treatment system is
that which is sent to drain from a final polishing unit, for example the drain
stream from an electrodeionisation (EDI) unit (Section 2.1.4), where the level of
concentrated impurities is still less than that present in the mains feed supply.
The other source may be from water that is sent to drain when the system is in
internal recycle. Unlike many applications, a pharmaceutical system is typically
designed to have all water in continuous motion with internal recycle loops on
the pre-treatment and the purification sections of the plant as well as the final
distribution loop. This is because the biofilm growth varies inversely with water
velocity: continuous motion of the water suppresses the creation of bacterial
colonies or biofilms on the pipe making it easier to maintain control of the
microbiological levels. This high-purity water is recirculated and becomes
the feed stream to the RO system, such that the reject water is still of a high
quality and would be suitable for reclaim back to the start of the water system.
The only potential problem with reclaiming this water is that the heat input
from the RO pump would also be recovered, such that the temperature of water
in the system would gradually increase. This may ultimately result in either a
cooling unit or dumping of water to reduce the temperature.
Clean in place (CIP) cycle effluent, depending on the type and stage of the CIP
process, may contain significant quantities of product residues and detergents
from the first rinse cycle or else could contain virtually pure water from final
rinse. Most CIP systems employ a series of cleaning procedures operated at