Down the drain: we need to rethink how we clean

Hundreds of chemicals can go down the drain from products we use everyday.

Individually, we use thousands of chemicals and very few of us think about whether they are harming the environment. We often think about buying a “green” detergent to wash our clothes, but the simple act of shampooing and conditioning our hair, even with presumably green products, results in numerous chemicals being washed into our sewers.

Despite our best purchasing efforts, our waste water treatment systems can sometimes remove many of these chemicals, however quite a number of chemicals are difficult to remove and end up being discharged into our coastal environments and waterways.

In the past, dilution was the solution for dealing with these long-lived chemicals that don’t break down. But with rising populations and non-coastal communities, dilution is not the solution of choice.

Regulations on discharge from our waste water systems means that any chemical that is not degraded will be at very low levels but many are residual in sediments and can be very harmful to our waterways, even at low concentrations.

This includes being toxic to organisms that live in sediments and binding to hormonal receptors in fish. So which chemicals cause problems and which ones are OK?

From drain to sewer

Our everyday lives introduce a wide range of chemicals into our waste water systems. The most common are surfactants and soaps associated with simple cleaning agents and detergents. Choosing highly biodegradable “green” detergents is a good start since they easily break down in the environment, but this is only the starting point in clearing your environmental conscience.

We also need to consider pharmaceuticals and their metabolites (the breakdown product of these pharmaceuticals), disinfectants, skincare products, deodorants, fragrances, flame retardants, pesticides, insecticides and plasticisers (the chemicals we add to plastics to make them easier to mould).

Detailed analysis of the discharge of waste waters from around Australia, and indeed the world, shows a list of around 70 chemicals that regularly find their way into the environment (recalcitrants).

Some of these are toxic and form a group known as “chemicals of concern”. All waste water is treated before being released into the environment, but advanced treatment is now becoming common to reduce the impact of these chemicals, although this is not available to all communities.

“Source” control, or stopping input into the waste collection system, remains the best option.

Problem chemicals

Some problematic chemicals of concern that find their way into our waterways are avoidable or their use can be drastically reduced.

Examples include:

• Triclosan: a highly effective biocide and antimicrobial now used in a range of mouthwashes, soaps, plastics and hand cleansers. It is debatable as to whether there is a case for its use outside of clinical environments.
• DEET: the active ingredient of many personal insect repellents. As with many other skin products, it is washed into the sewer
• Common plasticisers that mimics the hormone estrogen. Alternatives are available.

There is a long list of such chemicals https://envirofluid.com/info-library/commonly-used-harmful-ingredients-and-their-uses and these are just a few examples.

Removing stubborn chemicals

Research looks at how we can remove these chemicals from water. Wastewater treatment systems rely on the fact that molecules are either biodegradable or are removed in treatment.

If the molecule is not removed by these means, there is a propensity for environmental discharge. Typical addition treatment involves ozone treatment to destroy or fragment the molecule through oxidation and/or use of a physical barrier such as a reverse osmosis filtration membrane.

Using a combination of biodegradation, removal, oxidation and filtration is very effective and has been shown to break the pollution cycle for all but a very small number of molecules.

These molecules that still get through are highly problematic and one questions if such molecules should not be more heavily regulated. Not because they are any more toxic than others, but because they are hard to remove.

Moving to advanced water treatment is often the accepted norm, however using toxic chemicals will also upset these systems also. The ultimate solution is to use true biobased chemisties - and by the way, dont be fooled by green washing https://envirofluid.com/about-us/genuine-green-cleaning-being-abused-by-greenwashing - if it's bad for the waste water system or ocean outfall it's probably bad for you.