Disinfection of drinking water with the active substance chlorine dioxide

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Frequently asked questions

Answers about the biostream® products for cleaning and disinfecting drinking water with the active substance chlorine dioxide.

From the shelf life of treated water and the right cleaning interval to how chlorine dioxide works: here you will find our customers' questions answered in plain language.

The most important facts first

Scientifically proven, independently tested and proven in practice.

Proven efficacy
99.9 %

In 1,620 individual tests by Leibniz University Hannover against germs typical of drinking water, at a contact time of only 5 minutes.

Ready to use in
3 hrs

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

Dosage requirement compared with hydrogen peroxide
25×

lower: 6 instead of 150 mg/l for system disinfection under DVGW worksheet W 291. Evidence

Shelf life of treated drinking water

I disinfect 100 litres of drinking water in my motorhome. After two weeks (sometimes in the sun) I want to use the rest: can I still boil it for tea, drink it, or at least use it for showering?

Drinking water does not keep for long. The label on bottles of mineral water carries the note: "Use within 3 to 4 days." Water can only be made to keep by adding silver ions (heavy metals) to it. For health reasons we do not add heavy metals, but our products are compatible with these additives.

We do not recommend storing drinking water for more than 2 weeks. Boiled, the water can still be used, but you should definitely not use it for showering! The aerosols can travel directly into the lungs and cause legionellosis (Legionnaires' disease).

On holiday I only use two thirds of the 100 litres and top it up again, but only disinfect the added portion. Does the remaining third stay fully disinfected?

We always recommend refilling the water completely at regular intervals. When doing so, make sure that only approved drinking water hoses are used. When refilling, you can add biostream® ZERO to the tank water in drinking water quality and so effectively kill free-floating germs. You will find the right dosage in our dosing instructions under point 4, after entering the total amount of water in the tank above.

Is complete disinfection necessary, or is it enough to treat just the drinking water tank, for example?

We always recommend complete disinfection. If parts of the drinking water installation (pipes, boiler, etc.) are contaminated with germs, a biofilm has often already formed that can contain dangerous germs such as Legionella or Pseudomonas.

In certain sections of pipe, these biofilms also migrate AGAINST the direction of water flow. This is known as "retrograde microbial contamination". This is also why many water dispensers and dispensing systems become contaminated: at the outlet tap (right at the end of the water-carrying pipe), germs form through contact with the hand or oxidation with the air. These then migrate from there into the machine and/or the pipe. It therefore makes sense to disinfect the entire water-carrying system completely once, to ensure faultless drinking water. To counteract rapid recontamination, the incoming water should also be germ-free. In addition, only hoses approved for drinking water should be used for filling.

At what interval do I need to clean my tank?

"Can you tell us anything about the cleaning interval?"

We would refer here to the current DIN 2001-2:2009-04. It specifies that disinfection must be carried out if limit values are exceeded and whenever microbial contamination of the drinking water is suspected. Drinking water tanks in rented vehicles must be emptied by the operator after every rental and handed over in faultless condition. The system must be cleaned and disinfected every three months. This cleaning and disinfection must be carried out in accordance with DVGW worksheet W291. biostream® products comply with this worksheet. For privately used systems, the application of this standard is also recommended.

The three months mentioned are taken from DIN 2001-2:2009-04 and are a guide value. Our experience (and that of our customers), however, has shown that a cleaning interval can vary considerably. Why?

The following factors play a not insignificant role:

  • Quality of the water taken on board (temperature, microbial condition)
  • Quality of the hoses used to fill the tank with new water (storage location? approved KTW drinking water hoses?)
  • Age of the tank and the pipes (biofilm? which product was used for disinfection?)
  • Are filters fitted? How often are they changed?
  • Ambient temperature
  • How long the water is stored in the tank (is it completely refilled? does residual water remain? standing times?)

As you can see: many factors play a role when it comes to faultless drinking water. That is why there is no universally valid definition of what the perfect cleaning interval should look like. This is the reason for the somewhat "vague" wording "whenever microbial contamination is suspected" in the DIN standard mentioned above.

What else plays a role: the quality of the incoming water (germs? bacteria?) and the ambient temperature are important factors in the "recontamination" of drinking or tank water. The structural condition (dead legs, supply pipes routed over the engine block) also plays a major role.

Our trials at the University of Hannover under the direction of Prof. Dr. Werlein have shown that microbial contamination of drinking water can occur within four days! Here too, ambient temperature (summer), retrograde contamination and the interval of use were decisive factors. Please understand, therefore, that we cannot make a reliable statement on the subject of "recontamination".

How exactly does biostream® chlorine dioxide destroy germs and bacteria?

Chlorine dioxide (ClO₂) is a highly effective disinfectant used in water treatment, in the food industry and in other fields because of the way it works. Its ability to destroy germs, bacteria and other micro-organisms lies in its strong oxidising action. In detail:

1. Oxidation of proteins and enzymes

Chlorine dioxide oxidises the proteins of micro-organisms, including the enzymes needed for vital processes. Oxidation alters the tertiary and quaternary structures. This leads to denaturation, which ultimately disrupts the function of the proteins and inactivates the cell.

2. Penetration of the cell wall

Another advantage over other disinfectants: chlorine dioxide penetrates the cell walls of micro-organisms very effectively. This also applies to bacterial spores, which are protected by a robust outer layer. Chlorine dioxide penetrates these barriers and reaches the interior of the cell.

3. Disruption of lipid and fatty acid synthesis

Chlorine dioxide also attacks the lipids in the cell walls and membranes. This disrupts the integrity of the cell membranes and can lead to cell damage or cell death. In addition, fatty acid synthesis and other metabolic processes are interrupted, which destabilises the cell's energy balance.

4. Reaction with nucleic acids

There is evidence that chlorine dioxide reacts with the DNA and RNA of micro-organisms, which can cause mutations or breaks in the nucleic acids. Such damage is often irreversible and leads to cell death or inhibition of cell reproduction.

5. Formation of reactive oxygen species

When it reacts with organic substances in the cell, chlorine dioxide generates reactive oxygen species (ROS). These highly reactive components can cause further damage to lipids, proteins and nucleic acids, and intensify the cell's oxidative stress response.

Hydrogen peroxide is not a disinfectant? Correct!

"I use hydrogen peroxide for disinfection. Why should biostream® products be better?"

Hydrogen peroxide is not a disinfectant, only an oxidising agent! In the current UBA list of the German Environment Agency, which sets out all approved disinfectants, hydrogen peroxide is listed only as an oxidising agent because of its low disinfecting power.

Under DVGW worksheet W291 "Cleaning and disinfection of water distribution systems", hydrogen peroxide has to be used at a 25 times higher dosage to have the same disinfecting effect as the active substance chlorine dioxide used in biostream® products.

Chlorine dioxide compared with hydrogen peroxide: advantages and applications

Both chemicals are valued for their oxidising properties, but their applications and advantages differ considerably, particularly in water treatment, food processing and surface disinfection. This is how chlorine dioxide stands out:

Criterion Chlorine dioxide (biostream®) Hydrogen peroxide
Selectivity & efficiency high selectivity, effective against bacteria, viruses & protozoa; largely unaffected by pH fluctuations efficacy more strongly affected by environment, pH value & organic load
By-products & limit values does not react in a chlorinating way and therefore forms no chloramines and no trihalomethanes; the limit values of the Drinking Water Ordinance apply to chlorite and chlorate listed in the UBA list under the Drinking Water Ordinance only as an oxidising agent, not as a disinfectant
Odour & taste does not significantly change the taste/odour of the water can leave a slightly metallic taste
Efficacy at low concentration high, cost-efficient, lower risk of corrosion requires higher concentrations, increased risk of corrosion
Handling & safety more stable, less volatile, longer shelf life, better control more volatile, requires careful handling

Scientifically confirmed efficacy

Independent studies and decades of practical use demonstrate the performance of biostream® products.

Dr. rer. nat. H.-D. Werlein, Leibniz University Hannover

Leibniz University Hannover confirms efficacy

A study commissioned by biostream® GmbH from the Institute of Food Science and Human Nutrition at Leibniz University Hannover (led by Dr. rer. nat. H.-D. Werlein) confirms, in 1,620 individual tests, an efficacy of 99.9 % for the product biostream® ZERO against germs occurring in drinking water, at contact times of only 5 minutes.

biostream® products have been used successfully since 2001 in rail vehicles, on ships, in many hospitals and clinics, and by well-known beverage manufacturers. Dr. rer. nat. Hans-Dieter Werlein is responsible for the field of food hygiene and microbiology.

Biofilm study at the University of Hannover

Fighting Legionella and biofilms for good

Legionella (e.g. Legionella pneumophila) represent an often underestimated water hygiene problem and are the cause of Legionnaires' disease (legionellosis).

They settle in biofilms that can be tackled only poorly, if at all, by disinfectants containing hydrogen peroxide. Chlorine, too, has weaker disinfecting power than the active substance chlorine dioxide. Chlorine dioxide is included in the list of permitted treatment substances under Section 20 of the Drinking Water Ordinance.

Does your chlorine dioxide correspond to Dr. Humble's "MMS"?

"Your products produce chlorine dioxide. Does your chlorine dioxide correspond to that of Dr. Humble?"

No. Under the name "MMS", sodium chlorite solutions for ingestion are offered. The Federal Institute for Drugs and Medical Devices (BfArM) classified MMS in 2015 as a medicinal product requiring approval and giving cause for concern. Our products are not intended and not approved for combating illness. They serve to disinfect drinking water, including in times of crisis and for emergency provision in the event of a blackout, power cut and other disasters. More on this under Chlorine dioxide is not a remedy: MMS and CDL.

How long do biostream® ZERO and biostream® asepticaPRO keep?

Both products are supplied to you in two components: a bottle of liquid and a solid component. For the 250 ml containers you receive a tablet located in the cap of the bottle; for the larger containers, a separate bottle with a powder component. Before activation, this product combination keeps for around 3 years. The solid component (tablet or powder) must be stored dry: it is hygroscopic and draws moisture from the surrounding air. After activation (the tablet or solid component added to the liquid), the product formed after the reaction time keeps for two to three months, stored cool and dark in the closed original container. During this time you can effectively disinfect drinking water and effectively kill germs & bacteria (E. coli, Pseudomonas, Legionella). Any biofilm present is also destabilised.

Note: for larger containers (1, 5, 25, 60 litres), activation must take place COMPLETELY. Splitting into smaller containers afterwards is not possible, because the solid component separates out (the "muesli effect"), so activation to the correct standard cannot be guaranteed!

Why do I additionally need biostream® ZERO in my motorhome?

The contents of one vial of biostream® asepticaPRO are sufficient for 100 litres of drinking/tank water. Any bacteria present, such as E. coli, Legionella and Pseudomonas, are inactivated within minutes. If the dosage is followed, the tank no longer needs to be rinsed out separately, because the active substance chlorine dioxide in biostream® asepticaPRO is approved under the Drinking Water Ordinance to remain in the drinking water.

However, since in many cases biofilms have already been found to have built up in tanks and pipes, we recommend what is known as basic sanitation: here, biostream® ZERO is introduced into the tank at a higher dosage. According to DVGW code of practice W291, the contents of one bottle of biostream® ZERO (250 ml) are sufficient for 100 litres of tank content. After a contact time of 30–45 minutes, the water must be completely drained from the tank. After that, the water-carrying system is adequately disinfected and the germs are killed. At the next filling, it is then enough to add only biostream® asepticaPRO.

If you are not sure how heavily biofilm has built up in the tank and pipes, we recommend repeating the treatment.

Your advantages

  • Ready to use within just 3 hours
  • Effective across the entire drinking water pH range
  • Suitable for aluminium tanks
  • Suitable for disinfecting drinking water in times of crisis, emergency provision for blackouts, power cuts & other disasters
  • 25 times lower dosage requirement than hydrogen peroxide (6 instead of 150 mg/l for system disinfection, DVGW worksheet W 291)
  • Highly effective against Pseudomonas aeruginosa, E. coli & coliform bacteria, and Legionella (Legionella pneumophila)
  • Free from heavy metals (silver, copper)
  • Oxidative action on the cell membrane, proteins and genetic material simultaneously, 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 ›

Did you know?

Hydrogen peroxide is not an approved drinking water disinfectant. According to the UBA list (annex to the Drinking Water Ordinance), hydrogen peroxide is listed there only for the purpose "oxidising agent" and not as a "disinfectant".

biostream® ZERO, TRAVEL and asepticaPRO in various container sizes

From small containers to tanker trucks: the choice is yours!

Our customers fight biofilms, viruses and bacteria in very different scenarios: the dentist is concerned about the treatment unit, the yacht owner or camper about the perfect hygiene of the water tank. Our products are also used in industry against Legionella and E. coli.

biostream® products are available in various container sizes and packaging. We deliver as individually as necessary. For example, biostream® asepticaPRO comes in small 10 ml vials that take up hardly any storage space and are ideal for travel and outdoor expeditions.

Chlorine dioxide, the active substance in all biostream® products, is included in the list of permitted treatment substances under Section 20 of the Drinking Water Ordinance; the products comply with Article 95 (2) of the Biocidal Products Regulation (EU) No 528/2012.

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Facts that speak for us: biostream® products convince

With biostream® concentrates based on chlorine dioxide, you have the means to reliably disinfect drinking water tanks, drinking water pipes and soda maker bottles. Use the active substance of the waterworks without expensive plant technology.

The active substance chlorine dioxide has been used to disinfect drinking water in waterworks since the mid-1950s. Producing it there required complex and expensive plant that is no longer needed now. Produce effective chlorine dioxide yourself, quite simply, and benefit from its perfect efficacy against E. coli, Pseudomonas and Legionella!

Disinfect drinking water pipes, dispensing systems and tanks in motorhomes, camping vehicles and on boats and yachts in a legally compliant way. Germ-free drinking or process water for industry and trade can be achieved easily with biostream® GmbH concentrates. Talk to us. Our products are also suitable for disinfecting drinking water in times of crisis and for emergency provision in the event of a blackout, power cut and other disasters.

Hydrogen peroxide and silver-based agents are not an alternative

biostream® ZERO and asepticaPRO comply with DIN 2001-2:2009-04 (drinking water supply from small and non-stationary installations) and are effective across the entire drinking water pH range. Hydrogen peroxide is not listed as a disinfectant in the DIN standard. In the current UBA list of the German Environment Agency, too, it is listed exclusively as an oxidising agent, not as a disinfectant.

Look at the label of the disinfectant you currently use: if you find hydrogen peroxide listed there as the active substance, then, according to the German Environment Agency, you are using NOT a disinfectant but an oxidising agent that, under DVGW worksheet W291, has to be dosed 25 times more strongly to achieve the same efficacy as the active substance in biostream® products.

And if your product also contains silver: silver, too, is listed not as a disinfectant but only as a preservative. The DIN standard notes on this: "Only in exceptional cases where drinking water is stored without being used over a longer period. Preservation does not replace disinfection required for drinking water that is not faultless."

European Chemicals Agency (ECHA) Federal Institute for Occupational Safety and Health (BAuA)

Use biocides safely. Always read the label and product information before use. All statements on efficacy are based on the long-standing experience of biostream® GmbH, on information from the technical literature, laws and technical rules, and on positive customer references.