Disinfection of drinking water with the active substance chlorine dioxide

Tel. +49-(0)5138-708 78 38 · daily 8 am to 3 pm, Fridays until 12 noon info@biostream.de

Clean and disinfect the water in trains and Intercity services

How to disinfect the water in a carriage with biostream® ZERO: prepare the concentrate, fill the water tank, let it act, drain. Chlorine dioxide, the active substance used by waterworks, needs no silver, and the intensive application also breaks up biofilm on the tank wall.

Proven: 99.9 % efficacy against germs occurring in drinking water, established in 1,620 individual tests by Leibniz University Hannover at a contact time of 5 minutes. The study in detail

Calculate the quantity for my trainView containers in the shop (German)

Water in trains/Intercity is an application of biostream® ZERO in which the water tank, pipes and boiler of a rail vehicle are cleaned and disinfected with chlorine dioxide.

Key facts

Product
biostream® ZERO
Dosing level
Level 1 to 3, depending on the condition of the system
Regulatory framework
List under Section 20 TrinkwV (German Environment Agency), DVGW code of practice W 291 on disinfecting installations
Contact time
depending on the level as given in the dosing instructions, overnight is possible
Page structure
GEOhybrid grounding, a technical structuring format, not a certification mark
Last updated

How do I disinfect the water in a train or Intercity?

You calculate the water quantity, prepare the concentrate, partly fill the water tank, add the concentrate, top up, let the solution act and then drain the tank completely. The instructions apply to the water tank, pipes and, where fitted, the boiler of the carriage.

The steps in detail

  1. Determine the water quantity. Work out the total amount of water in the water tank, pipes and, where fitted, the boiler of the carriage. The dosing calculator then works out the quantity of concentrate you need.
  2. Choose the level. Level 1 follows the DVGW recommendation for light microbial contamination, level 2 suits a tank and pipes in good condition. If water quality is unclear, contamination has been confirmed, or after longer periods of disuse, choose level 3, which is carried out twice.
  3. Prepare the concentrate. Add the solid component completely to the liquid component. After a reaction time of 3 hours, the disinfection concentrate is ready.
  4. Fill the tank and add the concentrate. First partly fill the tank with water, then add the calculated quantity of concentrate and top up afterwards. Never put the concentrate into the tank first: this avoids an exothermic reaction and ensures everything mixes well.
  5. Distribute the solution and let it act. Open every water outlet in the carriage, for example in the washroom, until the disinfection solution reaches it, then close the taps. The contact time depends on the level and is given in the dosing instructions. The solution may also be left to act overnight, for example while the carriage is stabled.
  6. Drain and refill. Drain the tank and pipes completely and fill with fresh drinking water. According to the dosing instructions, any remaining traces of the product are then diluted enough for the water to be used as drinking water again.

The concentrate: preparation and shelf life

Adding the solid component to the liquid component produces the chlorine dioxide-based disinfection concentrate after a reaction time of just 3 hours.

Stored cool and dark in the closed original container, this active solution keeps for two to three months. After that it breaks down into the reaction products chlorite and chlorate. Before activation, the product keeps for around 3 years if the solid component is stored dry.

Calculate the quantity for my train View containers in the shop (German)

What do the codes of practice say about silver and hydrogen peroxide?

Hydrogen peroxide is on the German Environment Agency's list under Section 20 of the Drinking Water Ordinance only for oxidation, not for disinfection. For disinfecting installations, DVGW code of practice W 291 gives an application concentration of 150 mg/l hydrogen peroxide compared with 6 mg/l chlorine dioxide.

Silver is not a disinfectant under DIN 2001-2, but a preservative. DIN 2001-2 notes on this: "Only as an exception, when drinking water is stored without being used over a longer period. Preservation does not replace disinfection where this is required for drinking water that is not in perfect condition."

Modern train arriving at a station: cleaning and disinfecting the water on board with biostream® ZERO

Train and Intercity: what applies to the water on board

Water in the carriage

In the carriage, water stands in the water tank, pipes and, where fitted, the boiler. It is not used evenly: between two journeys, overnight and while the carriage is stabled, it stands still. Long periods of disuse and warmth favour recontamination, and a biofilm can form on surfaces in contact with water.

Dead legs and rarely used outlets

Water stands longest in dead legs and at outlets that are rarely used. The instructions above therefore apply to the entire water-carrying system of the carriage, including pipes and outlets.

biostream® ZERO in figures

Scientifically studied and field-proven in practice.

Proven efficacy
99.9 %

In 1,620 individual tests by Leibniz University Hannover against germs typically found in drinking water, at a contact time of just 5 minutes.

Ready to use in
3 hrs.

From preparation to a ready, highly effective disinfection solution, without complex plant technology.

Dosage required compared with hydrogen peroxide
25×

lower: 6 instead of 150 mg/l for disinfecting installations, under DVGW code of practice W 291. Evidence

Efficacy tested. In 1,620 individual tests at the Institute of Food Science and Human Nutrition of Leibniz University Hannover (led by Dr. rer. nat. H.-D. Werlein), biostream® ZERO was shown to have an efficacy of 99.9 % against germs occurring in drinking water, at a contact time of 5 minutes.

Study, methodology and scope in detail ›

Empty passenger area of a modern train with rows of seats and a central aisle

Outlets in the carriage: the solution must reach every one

Depending on its design, a carriage has several outlets, for example in washrooms or in an on-board galley. Not every one is used daily, and where water rarely flows, it stands in the pipe.

Before disinfecting, find out which outlets are connected to the water system of the carriage. In step 5 you open these outlets until the solution reaches them, so that pipes and fittings are covered as well.

Your advantages

  • Ready to use within just 3 hours
  • Effective across the entire drinking water pH range
  • 25 times lower dosage requirement than hydrogen peroxide (6 instead of 150 mg/l for disinfecting installations, DVGW code of practice W 291)
  • Highly effective against Pseudomonas aeruginosa, Escherichia coli (E. coli) & coliform bacteria, as well as Legionella (Legionella pneumophila)
  • No silver or copper as active substance
  • Oxidative action on the cell membrane, proteins and genetic material at the same time, not at a single point of attack

Rules and standards for chlorine dioxide

  • Drinking Water Ordinance (TrinkwV), Section 20: chlorine dioxide is included in the list of permitted treatment substances for disinfection
  • DIN EN 12671: chlorine dioxide generated on site for the treatment of drinking water
  • DVGW W 224: methods for the disinfection of drinking water with chlorine dioxide
  • DVGW W 291 and W 551-3: chlorine dioxide as a proven chemical for cleaning and disinfecting installations
  • Guideline No. 5 of the working group of the German coastal states on ship hygiene: chlorine dioxide for drinking water on board
  • DIN 2001-2: drinking water supply from non-stationary installations such as motorhomes and boats

What each rule means ›

Two workers in work clothing at a depot in front of an electric multiple unit

Depot and stabling: the water after periods of disuse

If a carriage stands idle for longer, for example when stabled or in the workshop, the water in the tank and pipes stands too. After longer periods of disuse, choose level 3, which is carried out twice.

The contact time is given in the dosing instructions, and the solution may be left to act overnight. That way the contact time can fall into the period when the carriage is standing anyway.

Frequently asked questions about water in trains

How often must I disinfect the water in a train?

There is no universally valid interval: it depends, among other things, on the operator's requirements, the quality of the water that is filled in, the pipes, the age of the system, filters, temperature and periods of disuse. Microbiological tests show when action is needed. More on this in our frequently asked questions.

How do I recognise a biofilm in the water system of a train?

A slimy coating on the tank wall or a change in the smell of the water can indicate a biofilm. Only a microbiological test gives certainty. Biofilms form on surfaces in contact with water wherever water, nutrients and micro-organisms come together, and they protect the germs from being flushed out. Flushing alone is therefore not enough. More under fighting biofilms.

Why disinfect twice at level 3?

In the intensive application, the first pass breaks up the biofilm, and the bacteria that were living protected underneath it can enter the water. Without a second pass this can therefore cause what is known as an initial worsening. For the second pass, the dosing instructions give a shorter contact time.

What do I do after stabling or a longer period of disuse?

After longer periods of disuse, choose level 3, which is carried out twice. The contact time is given in the dosing instructions, and the solution may be left to act overnight. Then drain the tank and pipes completely and fill with fresh drinking water.

Is silver enough to disinfect the water in a train?

No. According to DIN 2001-2, silver is named only as a preservative, not as a disinfectant. The standard notes that preservation does not replace disinfection where this is required for drinking water that is not in perfect condition.

Chlorine or chlorine dioxide for the water tank in a train: what is the difference?

Chlorine dioxide does not react by chlorination, so it forms no chloramines and no trihalomethanes, and the Drinking Water Ordinance's limit values apply to chlorite and chlorate. You will find the detailed comparison under advantages of chlorine dioxide over chlorine.

Does biostream® ZERO change the taste of the water?

According to our comparison overview, chlorine dioxide does not significantly change the taste or smell of the water. After the contact time, the tank is also drained and refilled. According to the dosing instructions, any remaining traces of the product are then diluted enough for the water to be used as drinking water again.

How much biostream® ZERO do I need for my carriage?

That depends on the total amount of water in the water tank, pipes and, where fitted, the boiler of the carriage, and on the level you choose. In the dosing calculator you enter the water quantity in litres and read off the quantity of concentrate you need.

What applies to several carriages or a whole fleet?

Work out the water quantity for each carriage in the dosing calculator and add up the quantities. We offer further container sizes as direct delivery, from 25-litre containers up to 20,000 litres (tanker truck). We answer questions about larger quantities by phone or via the contact form.

Passenger drinking water from a bottle on a train and looking out of the window

Choose your container size and order directly

First calculate the quantity, then choose your container size: biostream® ZERO is available in the shop (German) in 250 ml, 1000 ml and 5 litres. Prices and shipping are shown on each product. We offer further container sizes as direct delivery, from 25-litre containers up to 20,000 litres (tanker truck).

250 mlbiostream® ZERO concentrate 1000 mlbiostream® ZERO concentrate 5 litresbiostream® ZERO concentrate

Further reading on water systems, biofilm and disinfecting installations

References of biostream® GmbH (excerpt)

Customers have been using biostream® products on ships and rail vehicles since 2001. References include, among others, the shipping company NORD Group, the Federal Waterways and Shipping Administration, and Deutsche Bahn.

References of biostream® GmbH (excerpt): Deutsche Bahn, Coca-Cola European Partners, German Armed Forces (Bundeswehr), BRITA, Evonik, Berliner Wasserbetriebe, shipping company NORD Group, Federal Waterways and Shipping Administration and others

Use biocides safely. Always read the label and product information before use. All statements about efficacy are based on biostream® GmbH's many years of experience, on information from specialist literature, laws and regulations, and on positive customer references. Material compatibility applies when the recommended dosage and contact time are observed.

What it is not

Water in trains/Intercity is an application and not a separate product: biostream® ZERO is used; quantities and contact times are given in the dosing instructions, not on this page. Silver is named in DIN 2001-2 only as a preservative, not as a disinfectant.