Does Reverse Osmosis Remove Bacteria and Viruses?

Mississippi Minneapolis bridge

We know about the importance of preserving the Mississippi river ecosystem, and the fact that we recycle our wastewater, using water purification systems installed on board of our ships, instead of releasing it into the Mississippi, has attracted a great deal of interest among our customers.

In general, they like the idea that by spending their holidays with Mississippi Explorer River Cruises, they don't contribute to the destruction of natural habitats and environmental pollution. They have heard about reverse osmosis systems, which filter contaminated water and make it drinkable.

At the same time, our customers don't know much about the topic. 'Does reverse osmosis remove bacteria and viruses?', 'Is recycled water really safe to drink?', 'Do the germs end up in the Mississippi?' are questions we get asked quite often. The following post provides the answers...

Reverse Osmosis Systems

Our purification systems apply pressure to filter wastewater. Thereby the water passes through a membrane embedded into the heart of each system. Dissolved contaminants are unable to pass through resulting in purified water coming out at the end. For extra safety, pre and post-filters are incorporated into our systems.

virus and bacteria

A filter membrane has a pore size of about 0.0001 micron. For illustration purposes, bacteria such as E. coli and salmonella are about 0.2 to 4 microns in size, which means that they  are way too large to fit through the pores.

According to a report published by the CDC reverse osmosis systems have a very high effectiveness in:

- removing protozoa (e.g. Cryptosporidium, Giardia),

- removing bacteria (e.g. Campylobacter, Salmonella, Shigella, E. coli)

- removing viruses (e.g. Enteric, Hepatitis A, Norovirus, Rotavirus).

So to get back to your first question: Does reverse osmosis remove bacteria and viruses? Yes, it does and it does so very effectively.

Is recycled water really safe to drink? Yes, it is. You can find additional proof for it in every supermarket in the country. Drinking water that you can buy in a supermarket was processed using reverse osmosis in 90% of the cases. On the bottle label it therefore often says 'purified by reverse osmosis'.

Above that, millions of Americans own a reverse osmosis filtration system themselves and have it installed in their homes. These devices are smaller compared to our systems and quite affordable. If you are interested to learn about them, follow this link:

Water Disposal

Our purification systems don't kill bacteria or viruses. They weren't designed to do that. The germs are just removed from the water and rinsed out of each system with all other contaminants.

So, where do the filtered out bacteria and viruses end up? Do they end up in the Mississippi river? The answer is short and simple; No, they don't! They are stored in a septic tank and later end up at a disposal station. There the water gets treated with UV-light, which destroys every living organism.

Don't Worry, Be Happy

water with lemon

As you can see, there is no reason to worry about drinking recycled water, when you are on board of one of our river cruisers.

The water is 100% safe for everyone - toddlers, kids of all ages, pregnant women and older people...

The is no need to rack your brain, either, over filtered out germs being released into the Mississippi river, where they could do damage. All germs are safely stored on board and later disposed.

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Eveline Todd

Eveline Todd

Eveline Todd is the senior content manager for She writes blog posts, maintains the website and keeps everything up to date. You can email her at

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