Monitoring the hygiene of ultra-pure water distribution systems

Wherever a constant high quality of ultra-pure water is required for industrial and chemical processes, measures have to be taken to guarantee this in storage, distribution and monitoring systems. This also applies to the ultra-pure water used for rinsing and cleaning purposes, in the laboratory, or whenever exacting demands are made of microbiological and chemical purity. And not only that: the legal requirements and resulting technological demands to be satisfied in water purification are increasingly being tightened. In order to comply with all these requirements Bernd Kraft® focuses on the highest possible safety and security of components and processes. To ensure that water at the point of use is ultra-pure and microbiologically sterile, Bernd Kraft® integrates the storage, disinfection and distribution of ultra-pure water in its overall concept. The high quality of ultra-pure water all the way to the consumer is ensured by continuously disinfecting it and sanitizing the treatment facility and distribution system.
A description is given below of the actions Bernd Kraft® takes to minimize the microbial count in its demineralized water distribution system:

1. Cutting-edge water purification technology

Bernd Kraft® banks on state-of-the-art processes and systems and works with a cutting-edge five-stage ion exchanger system. The main “beast of burden” is a demineralization system that reduces cation and anion content to a conductivity of ca. 2 – 4 ?Scm-1. This is followed by processing in a polisher ion exchanger in which the water undergoes three-step demineralization (cation, anion and cation exchanger) in a multi-step process. This causes conductivity to be lowered even further to a value of between 0.06 and 0.2 ?Scm-1. The software-controlled system enables quantity- and conductivity-induced shut-downs to be controlled. In so doing, the supply of ultra-pure water to ongoing production processes is always guaranteed as there are no interruptions.

2. Passive measures

In a retrofit action Bernd Kraft® replaced all piping with high-performance PP-n and stainless steel piping. In so doing, Bernd Kraft consistently applied the 3D rule — a standard pertaining to the cleanability of piping in the pharmaceuticals industry. In addition, aeration of the supply tank is done via a carbon dioxide absorber fitted with a HEPA filter.

3. Active measures

Before drinking water enters the demineralization system, it undergoes UV disinfection followed by being conveyed through a 0.45 micron membrane filter. A high-performance UV lamp is integrated in the distribution system, in addition to a series-connected membrane filter with filtration ratings of 0.45 microns and 0.2 microns. A continuous flow prevents the water from standing still, thus rendering microbe buildup difficult. Chemical sanitizing with a special disinfectant is performed regularly. In the process the ion exchanger and the distribution system are sanitized including all dispenser and sampling points. Finally all the pumps and the UV lamps are cooled and air-conditioned so as to reduce the introduction of temperature increases in the distribution system.

4. Monitoring

When it comes to safety Bernd Kraft® implements a series of measures so that the quality of this highly sensitive, high-performance system is continuously checked and maintained at a constant high level:
  • On-line temperature and conductivity measurement
  • 24/7 monitoring by software and alarm escalation to a security firm
  • Measurement of the silicic acid concentration value of the ultra-pure water several times a week: in so doing, the degree of resin exhaustion of the multi-step system is checked. Here, the internal limit amounts to less than 5 ppb.
  • Third-party sampling and analysis of microbial loading: this is done approximately every two weeks by our partner, the Ruhr District Institute of Hygiene, to monitor the effectiveness of our hygiene measures.
  • Routine off-line TOC monitoring (between 30 – 60 ppb C/l), and
  • Routine sampling and analysis in compliance with the specifications of the European Pharmacopoeia.

Bottom line: Bernd Kraft® produces water that satisfies extraordinarily high quality requirements for use as a resource in other production processes.