Silver/copper ionisation is used world-wide as an effective means of controlling legionella bacteria and many other water-borne organisms in water systems; this type of water treatment process is described in the Guidance Documents of the following:

• The Health & Safety Executive, the Approved Code of Practice and Guidance: Legionnaires’ disease (L8).
• The European Working Group for Legionella Infections (EWGLI), European Guidelines for Control and Prevention of Travel Associated Legionnaires’ disease.
• World Health Organisation, Guidelines for Drinking Water Quality; Addendum for Microbiological agents in drinking water.
• NHS Estates, draft HTM 2027/2040, the control of legionella, hygiene, safe hot water, cold water and drinking water systems.

This economic and environmentally friendly water treatment system is based on the controlled release of low levels of silver/copper ions into the water stream and within EEC Drinking Water limits. The positively charged ions are attracted to negative charge sites on the walls of water-borne bacteria cells. Once attached to the cell wall the ions cause distortion of the cell body and prevent the cell from taking in nutrient, causing it to die. This process attacks water borne legionella and over a period of time breaks down bacteria which is harbouring in bio-film on the internal aspects of pipes, calorifiers and tanks; thus significantly reducing a major source of legionella.

All the above guidelines recommend the levels of silver and copper at which the system should operate. The rate of release of ions is directly proportional to the current applied to the electrodes and this should be maintained automatically. The treatment level can then be controlled by a flowmeter, flow switch or timer.

Where systems are installed in hard water supplies scale can be an issue and affect the efficacy of the system. Equipment should be chosen that is specifically designed to operate efficiently under hard water conditions.

Silver/Copper Ionisation is now used world-wide in many applications, which include:

• Domestic hot & cold water systems in the NHS and private hospitals, Care Homes & Hotels.
• Public & private swimming pools and jacuzzis.
• Food sector for washing “ready to eat” bagged salads for major supermarket chains.
• Industrial plant such as car body washing prior to painting for a number of leading international manufacturers.
• Decorative water features for shopping centres such as the Bluewater and Trafford Centres.

There are also significant financial and maintenance benefits associated with ionisation water treatment which should always be considered when seeking a highly effective water treatment process.

Article by:
Ian Bateman
Executive Manager
T.P. Technology
T: +44 (0)1494 535576
E: info@tarn-pure.com