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If you like the podcast, “How Stuff Works”, then you’re quite likely to like reading this post about what happens to used laundry detergent down the drain.

If you don’t like the podcast, then we’d advise you don’t read on, because we’re doing it all. History of, current situation, and a little science. 


In the good ol’ days. 

Soaps were the first washing aid to be used, aiding hand washing with a washboard. Early soaps did not breakdown. By the 1950’s there were mountains of foam building up in sewage pipes. Apart from being very inconvenient, the water was quite toxic to small organisms.

This problem spurred on the development of detergent - a soap (or surfactant) that is readily biodegradable. It also spurred on the development and addition of chemicals to make the surfactants perform better. 

One such chemical was phosphate. Phosphates are very bad for waterways. Amongst other things, they cause blue-green algae outbreaks which are toxic to ecosystems and waterways. 

For this reason, many companies have phased phosphates out of their detergent. Unfortunately, Australia has amongst the weakest laws on this matter (who’s surprised), meaning the phase out here was voluntary (2). 


Where wastewater goes: 

Nowadays, wastewater heads off to wastewater treatment plants where it goes through a series of physical, chemical and biological processes to remove solids, organic matter, pathogens, metals and often added nutrients. Most of the pesky phosphates are removed throughout this process. 

It’s a four stage process, by the time it hits stage three, it’s close to drinkable. After the final stage of treatment, the wastewater is nearly indistinguishable from drinking water. Neat and gross huh?!

Once it’s been through the final stage, it’s redistributed into the environment, vineyards, parks etc. If it can’t be redistributed, it's released into the environment, so long as it’s been proven to be at a standard that won't cause harm.

And the laundry products?

They don’t cause many problems at the plants anymore. Most of the ingredients in many detergents, and certainly all the ingredients in ours are biodegradable, and easily broken down at the plant. 

You still need to watch out for detergents that contain phosphates (don’t buy from powder people still including phosphates - we know too much), especially if you’re considering using grey water in the future. 

Apart from that, thanks to modern science, worry not. Our wastewater are literally turning your dirty washing back into gold standard clean water, used to make your wine 😉. 

Circle of laundry life hey. 

Post script, Dirt’s a great choice for red wine stains. 



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