Introduction
Water should be used, reserved and distributed in a way so that there is no place for contamination. Even though many systems are installed, validated but it should be done by the approval of quality assurance department.
Water sources should be monitored for contamination and proper documentation should be done regarding its usage.
Techniques
Control techniques to reduce bio contamination for purified water can be used either alone or in combination.
- A continuous turbulent flow should be maintained within distribution system to reduce biofilms formation
- Considering the qualification of the system and its performance velocity should be maintained which can be determined by Reynolds number
R = ρVD /µ
R = Reynolds number
V = Free stream fluid velocity
D = characteristic distance/ pipe diameter
ρ = Fluid density
µ = Fluid viscosity
- Even short fluctuations in velocity cannot produce contamination unless the flow is stopped or reversed
- The design of pipework should be of a minimum possible length
- For surrounding temperature systems pipework should be separated from neighboring hot pipes
- Dead leg in pipework should not be more than 1.5 times of branch diameter and it can be overcome by using appropriate design
- Pressure gauges are to be separated from system by inserting membranes
- Hygienic diaphragm valves should be used
- Pipework should be adjusted to facilitate drainage
- Microorganisms growth can be stopped by
- Using sources of UV radiation in pipework
- Maintaining a temperature of 70-80o C
- Cleaning the system using hot water with more than 70oC periodically
- Sanitizing with ozone or chemical agents. Careful consideration is required to remove the chemical before using water.
