What’s in Wastewater: the good, the bad and the ugly…

Quick! Without thinking, what’s the first and most important need for a human to survive?

a) Food

b) Water

c) Sleep

d) Shelter

e) Oxygen

f) Fuel

If you answered (b) or (e), congratulations! You acknowledge the necessity of keeping our Earth clean. Or do you? Maybe you’re not thinking as deeply about it as I do, but now that I’ve caught your attention, I’ll get to my main point soon enough. Most importantly however, you understand the two key elements that humans (and countless organisms, I might add) require. But do you understand that there is a finite amount of these elements on Earth?

This blog will be more focused on water rather than air, as essential as both are, I feel in a better mood to talk about the latter. So let’s get to the point, shall we?

It truly is aesthetically pleasing. (Source of image)

Wastewater. What does the word mean to you? I know you may be thinking: “it’s water that is no longer usable.” But this couldn’t be further from the truth. One such definition, considered the universal definition as included on Wikipedia:

“Any water that has been adversely affected in quality by anthropogenic influence.”

In my view, this definition applies to most forms of wastewater. However, I think that definition can be expanded beyond human influence alone, of course, if we consider that there is no natural system that has a universal salinity, acidity, oxygen level and temperature that will suit every organism. For example: seawater – have you drunk it before? I have, and it was awful. Nor would I recommend it for watering my garden. Yet there is a load of biodiversity in our oceans, and I speculate that’s part of why we have biodiversity: because of the numerous combinations of possible natural water conditions that exist in the categories mentioned above. Likewise, pure water is also known to be harmful, disrupting the flow of electrolytes in essential organs.

Pure water will try to steal the ions from your bloodstream!

Having acknowledged the importance of biodiversity, let’s see it from the human perspective. I consider wastewater to be any type of water in a state that is directly unusable for humans in any way whatsoever, whether that is drinking, irrigation, swimming, or cleaning; this isn’t even an exhaustive list of uses. None of these types of water built for these uses will necessarily have the same mixture of chemicals either. It’s fascinating, isn’t it? How versatile the element truly is.

Since there is (arguably) not a single chemical combination of water that can be used in every possible situation, it can be argued that all water is wastewater. Indeed, many of my own classroom peers hold this view as it does hold weight.  There’s more to it though, the water you drink and use was once wastewater, having gone through a series of treatment processes to suit your thirsty needs! That is a topic for another time; today, I wanted to talk further about what wastewater is more concretely and less ambiguously, and I have decided to categorise them as done by the Queensland Department of Environment and Heritage Protection.

The local wastewater treatment plant on Alkimos!

The wastewater we are most familiar with is domestic wastewater, which covers everything that comes from households, business workplaces, and public areas.  It is water that is used in toilets, showers, baths, sinks, pools and laundries; all of which ends up in sewage pipes leading to a local treatment plant. Beyond this, wastewater that contains by-products of industrial activities is called industrial wastewater (duh), coming from operations such as food processing, metal refining, oil extraction and many more! Finally, stormwater occurs as a result of runoff onto urban and agricultural areas, taking along any materials pollutants that stand in its way! Unfortunately these are highly difficult to treat as any that does not end up in drainage sewers (separately  from the above two), will end up in natural systems including lakes, streams and the ocean!

A non-exhaustive list of the constituents, covered in these types of wastewater will be listed below:

  • Microplastics
  • Food waste
  • Oil and grease
  • Pharmaceuticals
  • Washing agents (soaps and detergents)
  • Nutrients (phosphorous, nitrogen)
  • Clothing products (cotton, textiles, polyester, pigments)
  • Poisons (pesticides, organic compounds, herbicides, synthetic chemicals and heavy metals)

Keep in mind each constituent can be found in multiple categories!

To make it easier to understand, I thought I’d make it into its own spectrum, based on difficulty to treat and harmfulness to humans and the environment! Not necessarily backed up scientifically, but based entirely on my own intuition. Feel free to add to it, and correct me where I may be wrong.

blog 1 spectrum.png
(image created by Alex Smith)

I know it is a very broad spectrum, and will consequently have inaccuracies. But the most important message to gain here is that it is highly difficult to treat the contaminants that end up in the stormwater due to: the source of pollution not having a direct source, not knowing exactly where the pollutants end up, as well as the wide spread (hence low concentration) of pollutants making them difficult to purge from the water entirely.

So why does wastewater need to be treated in the first place? You previously acknowledged that water is vital for survival. But what about the importance of keeping it clean? The reasoning: water is finite, and less than 3% of this is fresh – if we did not recycle and reuse our water, the human race would cease to exist. And that is why our wastewater treatment plants exist – yes, let me say again, our water supplies are recycled from wastewater.

pie charts
The natural distribution of freshwater across the globe.

An overlooked example of industrial wastewater that is not able to be treated at a plant comes from a controversial engineering practice known as fracking! Simply put, it is a process that allows for oil and gas to be easily extracted from deep under the ground, and is regarded as economically viable. This sounds great on the surface, but realistically, long term it is not.  Over 1,000 chemicals are involved as a result of the process, and worse, they end up in surrounding aquifers and surface water systems. These chemicals sadly include radium, selenium and lead – nasty! The worst part? They have the same issues as stormwater as far as the treatment process goes.

So how do we compromise? One proposed solution is that we implement centralisation of wastewater treatment methods. In summary, it is the extraction, usage, followed by treatment of water done simultaneously during the fracking process, in order to minimize by-products from reaching into the water system. To me, it sounds good in theory, but in practice, maybe not so much. It seems too good to be true to keep contaminants entirely from reaching the natural water systems, but fracking may very well continue as long as the proponents push for it. So, regardless of your view, a clean way of doing so will ensure that both sides can win. Until then, I continue to say no to the practice.

I hope that this was a pleasant read for you, and that you learned something. Please continue discussion below, I am sure to learn just as much from you!


5 thoughts on “What’s in Wastewater: the good, the bad and the ugly…”

  1. I really enjoyed your breakdown and analysis of the water issue, it’s something i skimmed over really quickly, I’m going to try link your blog if I ever need to reference the concept again.


  2. Thanks for sharing and for discussing the importance of processing wastewater given that only 3% of water is considered fresh, something I didn’t previously know. I like how you touched on the issue of fracking, it’s too bad we don’t have any mining engineers in the class to give their opinions as I feel as this issue has only been negatively portrayed in the media and I would be curious to hear both sides of process (and also because debates around “hot topics” are entertaining haha).


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