Knowledge Base

Holland Water and the Bifipro® system have the required certificates and authorisations on both national and international levels for potable and cooling water applications. Holland Water is also closely involved with legal developments for Legionella treatment in general and copper and silver ionisation in particular; in this manner we are striving towards a future where everybody can have access to safe water.

Legislation and Certifications

The Dutch Minister of Infrastructure and Water Management recognises, in her letter from January 2019 to the House of Representatives, the development towards new healthcare systems and is having the law changed so that so called ‘care homes’ where continuous medical care is provided are included in the list of priority locations. Leading up to this, the Human Environment and Transport Inspectorate will act (less strict) in anticipation.


The proposed adjustments are partially a consequence of the ZEMBLA broadcast from 12th December 2018, to which Holland Water provided assistance and collaboration. The broadcast can be viewed here to the right.

Technique Comparison Table

An objective overview and comparison of alternative techniques for the treatment of potable water:

 Copper and Silver IonisationAnodic OxidationChlorinationFlushing and HeatingChlorine DioxideUltra Violet Light (U.V.)Membrane Filtration
Permitted in the NetherlandsYesYesNoYesNoYesYes
Required concentrationsCu = 0,2 - 0,8 mg/l
Ag = 0,02 - 0,08 mg/l
0,3 - 0,5 mg/l2 - 4 mg/l80ºC for 30 min
0,5 - mg/l as CLO210 - 0,1um
Application documented in literatureYesYesYesYesYesYesYes
Residual effectYesNoNoNoMore stable than chlorinationNoNo
Re-colonisation time6 - 12 weeks1 - 2 weeks1 - 2 weeksVariesNo informationOnly locally effective (gatekeeper)Only locally effective (gatekeeper)
Temperature effectNo effectDisintegrationDisintegrationNot applicableDisintegrationOnly locally effective
Only locally effective
pH effectElevated pH (> 8.5) may affect operationElevated pH (> 8.5) may affect operationElevated pH (> 8.5) negatively affects operation
No effect
No effect
No effect
No effect
By-productsNoneNoneTrihalomethanes (THMs)NoneChlorate and ChloriteNoneNone
Impact on taste and smellNoneYesYesNoneMinimal despite high concentrationsNoneNone
CorrosionNoneYesCorrosiveCorrosiveVery corrosiveNoneNone
Effect on synthetic pipesNoneYesYesYesYesNoneNone
Maintenance4/year inspection of electrodes and Cu + Ag concentrationsChlorine measurements and 4/year system checkRules for transport, storage and handling in effect. Routine inspection of concentration, corrosion inspectionIncineration is possible; labour-intensiveRules for transport, storage and handling in effect. Regular inspection of concentration, corrosion inspectionRegular cleaning otherwise effect wears off quicklyClean filters regularly or replace
Reduction of effectivenessNoneDisintegrates at high temperatures and over distanceDoes not eliminate biofilm. Loses effectiveness at high pH. Disintegrates at high temperatures and over distanceDoes not eliminate biofilm and re-colonisation is possible. Disintegrates at high temperatures and over distanceOnly locally effective; only as a water system is in direct contact with UV, otherwise it does not eliminate the biofilmOnly locally effective, does not eliminate biofilm

Separate copper and silver electrodes vs. copper and silver alloys

Systems that work with a so called alloy of copper and silver work inadequately accurate. Scientific research on this was published in 2015 in the ‘Journal of Water Process Engineering‘. Practice has also indicated that alloys of copper and silver are inadequately effective.

The most effective working of copper and silver ionisation is realised with dosing of 200 – 400 µg/l Cu (copper) and 20 – 40 µg/l Ag (silver). Both science and practice indicate that alloys are unable to constantly and accurately dose the required concentrations. Silver concentrations are often dosed insufficiently with an ineffective treatment of the (potable)water for Legionella bacterium as a consequence.

Holland Water’s Bifipro® systems treat potable and cooling water with separate copper and silver electrodes. Additionally the systems are equipped with a patented current control (polarity switch) with which the dosing is proportionally adjusted to the real-time water flow and the electrodes do not dirt as quick. This patent also ensures a longer period of use for an accurate and efficient treatment of the water.


What is Legionella?

Legionella is a bacteria. A micro-organism such as Norovirus, E-coli, Hepatitis A, Cryptosporidium, and Pseudomonas. A potential contamination risk for water and responsible for the deaths of millions of victims world-wide. Legionella pneumophila causes the Legionnaire’s disease, a possibly fatal form of pneumonia. These Legionella bacteria find their way into the human body through the respiratory system by inhalation of small contaminated water droplets and/or water mist.

Potentially everyone is susceptible to Legionella. However, at greatest risk are: small children, the age group of 45 years and above, those with a weakened immune system, people with breathing difficulties and/or kidney problems, as well as the group smokers and drinkers.

When does Legionella occur?

The problem of Legionella is caused by contamination of water installations with biofilm that consequently acts as a breeding ground for other bacteria. Such contamination can in particular be caused by stagnant water and the heating up of cold water. In these situations, all other techniques or interventions are inadequate and the Ministry of Infrastructure and Environment has also labelled the technique of copper- silver ionisation as the ultimate solution.

As soon as bacteria multiply, they deposit polysaccharides which function as a sort of glue and this aids the bacteria to collect on the water pipe wall or on another surface –in the case of a cooling tower. Biofilm is a layer of built up bacteria that usually easily forms on the insides of a water pipe or on another surface. Biofilm is the ideal breeding ground for the Legionella bacterium.

The Legionella bacterium can survive in waters with temperatures between 0°C and 63°C, but mostly multiplies between 20 – 45°C. The growth rate is at its maximum at temperatures of 30 – 40°C (body temperature!).

Legionella Scan

With the Legionella Scan owners and managers of collective mains water installations can discover step by step if they are taking the correct actions in buildings, and if they comply with the legal regulations applicable to them. The Legionella Scan functions as a step by step tool that makes clears with which rules, and in which way, you must comply. With the Legionella Scan you can gain insight into the complete scope of the legislation around Legionella prevention, but this tool can also provide an objective overview of the obligations and the required measures.

The Legionella Scan is, after a one-time registration, available free of charge and is primarily suited for manages of collective water mains systems in hospitals, care facilities, asylum seekers centres, prisons, swimming pools with saunas, hotels, bed & breakfast locations, campsites, service station restaurants with showers and marinas.

After having completed the scan you can print a report. This report provides a good indication of the status of your system in relation to the protection against Legionella. The result of the can eventually indicates which form of management is possiblle and required or not. The scan can naturally also be completed anonymously.