All communities need water to drink. And, although we may not always like to think about it, all communities produce sewage water. Fortunately, this sewage water can be recycled – but is recycled sewage water safe for drinking? Read on as we explore this in more detail.
Recycled Water: Is It Safe for Human Consumption?
Okay, it’s a simple question, so let’s start with a simple answer. Yes, recycled sewage water is safe for drinking.
This is because sewage water is just water – it’s just H2O – but it’s water with lots of nasty extras, like:
- Bacteria
- Viruses
- Amoebas
- Heavy metals
- Chemicals and other pollutants
If these things get into our system, it’s very, very bad. Illnesses like diarrhea and dysentery, giardiasis, typhoid, E. Coli infection, and salmonellosis can all result from drinking contaminated water. But, if the pollutants are removed and only clean water remains, there’s no problem. Recycled sewage water is safe for drinking, as long as the proper measures are used to treat and clean it.
How Sewage Water Can Be Turned into Drinking Water
There are a number of different ways in which sewage water can be treated, leaving us with safe, clean drinking water. We’ve covered a few below to give you an idea of how the process can work.
Reverse Osmosis
In osmosis, fluids flow down a concentration gradient, moving from an area of high pressure into an area of lower pressure and traveling through a membrane as it does so. This is a natural occurrence, and it takes place within the cells of our very bodies almost constantly. Reverse osmosis, as you might expect, is the opposite.
Instead of flowing down a natural gradient of pressure, fluids are forced to return the other way. An applied pressure is utilized to push the fluid back through the membrane to the initial area of high pressure. In natural osmosis, the pressure gradient should even out, so no further materials are forced through the membrane. With reverse osmosis, there is a repeated movement across the membrane, achieving filtration.
Ozonation
Ozone is just oxygen, but rather than a molecule made up of two oxygen atoms (O2), it has three – O3. Ozonation is the process of using this oxygen molecule to disinfect water and remove pathogens. The process also achieves residual disinfection, which means it inhibits further microbial growth in the water after it has been treated.
Studies have found that ozonation can also improve the taste and coloring of water, as well as remove metals like iron and manganese. It may be more effective than traditional forms of disinfection, like chlorination, although chlorine treatment may be used alongside ozone treatment.
Biofiltration
Biofilitration is a general term for filtering wastewater through biological media. The mechanical process of filtration remains unchanged – water passes through the medium, which traps and removes pollutants and pathogens. However, the biological element makes this form of filtration more effective.
The biological media interacts with the pollutants and contaminants within the water. The media digests some of these harmful contaminants, leaving behind more benign byproducts that can be easily removed. Different types of biomaterial can be used to remove specific contaminants, although the filtration media will need to be replaced periodically as it becomes less effective over time.
UV Disinfection
Ultraviolet (UV) light exists just outside of the visible light section of the electromagnetic spectrum. Electromagnetic energy with a wavelength of between 400 and 10 nanometers will be classed as UV. Exposing sewage water to UV radiation can effectively kill some of the residual bacteria and pathogens that have not been removed through other methods.
UV disinfection typically takes place towards the end of the treatment process. It’s a way to effectively “mop up” any contaminants or pathogens that may be left over after other forms of treatment.
Combining Methods
You may have noticed a recurring theme in the methods listed above. They don’t tend to work in isolation. For example, ozonation may be better than chlorination in some ways, but the two methods are often deployed together in order to achieve more comprehensive treatment. Similarly, biofiltration requires additional removal of byproducts. We also mentioned that UV disinfection is typically used towards the end of the overall treatment procedure – it’s not a single, standalone method of treatment.
In most cases, facility managers will deploy a range of different methods to achieve clean drinking water. Potable water is governed by a range of different rules and regulations and is held to an understandably high standard. It’s imperative that these standards are met to ensure public safety and ongoing viability for water recycling.
Why People Remain Squeamish About Sewage Water
If recycled sewage water is safe for drinking, why do so many people still have a problem with this? One of the factors at play here is something that has been termed “magical contagion.” Basically, it doesn’t matter how much treatment the sewage water has undergone, and it doesn’t matter that it’s been tested and shown to be clean – it’s still sewage water. The very idea of drinking something that was once sewage it’s horrifying for many of us – even though all the science tells us not to worry.
There’s also the matter of trust. The infamous Flint, Michigan, drinking water crisis did not involve sewage water, but it did expose thousands of people to harmful contaminants and pollutants. Twelve people died as a result of drinking this water, and millions of people across the United States were left wondering if they could truly rely on what was coming out of their faucets. Municipal treatment and processing facilities must win the trust of the local population if they are recycling sewage water into drinking water.
Why Recycling Sewage Water Matters
If some people still have a problem with drinking recycled sewage water, then why bother? Why not just keep everyone happy with fresh water from other sources? Well, because recycling sewage water into safe drinking water isn’t really a choice – it’s a necessity. Here’s why it matters:
- Drinking water is something all of us need, and other sources are in short supply in drier areas of the country.
- Wetter areas of the country export much of their water to other states, leaving their own ecosystems in peril.
- Sewage water needs to go somewhere – if it is not recycled, it still needs to be treated and made safe.
- Recycling water encourages ecologically sound processes, reducing the environmental impact on communities, particularly in urban areas.
By recycling sewage into safe drinking water, communities become self-sufficient and self-sustaining. As resources become increasingly scarce, a focus on effective recycling will be vital for communities with growing populations and soaring water requirements.
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