The Disposal of Soaps and Detergents

The Disposal of Soaps and Detergents
EPA 547/04—April 2004
A brief history of soaps and detergents
Old-fashioned soap worked because it was made up of chemicals called ‘surfactants’, which lowered
surface tension in water and broke down fatty materials—in other words, they decreased the fabric’s
hold on the dirt and they also dissolved some dirt particles. In the early 20th century, as people
became more familiar with bacteria as a cause of disease, antiseptic chemicals such as ‘carbolic’
(phenol) were added to household washing materials.
These original soaps did not degrade in the environment and their residues remained in waterways
and water treatment plants. By the 1950s, drains and rivers often carried persistent mounds of
foam, and the water became toxic to small organisms living in the water.
Manufacturers therefore sought to make washing powders ‘biodegradable’—to decompose naturally
as soon as possible after use. Water hardness is a significant factor in the effectiveness of modern
detergents; the harder the water, the more detergent is required. The ions in ‘hard’ water,
particularly of calcium and magnesium, bind to the surfactant components and leave an unpleasant
scum on the water—and clothes.
So manufacturers added ‘builders’, which bind to and essentially remove these ions and, in doing so,
‘soften’ the water. (You can tell the difference between water that has been passed through a water
softener and water that hasn’t and remains hard, by the ‘sudsiness’ of soap used in the shower).
Phosphates have been the builder most commonly used in detergents. However, because excess
phosphates cause problems in our waterways, some detergent manufacturers have developed
‘phosphate-free’ detergents. (Although these detergents are marketed as such, they are not always
entirely phosphate free).
What does ‘biodegradable’ mean?
The term ‘biodegradable’ refers to the ability of a material to be broken down, by a group of
biological organisms called decomposers, into various other compounds. Decomposers are a
necessary component of a balanced ecosystem present in natural waters and sediments, and are
encouraged in sewage treatment works. Bacteria are the most common decomposers.
The Australian Standard for biodegradability (AS1792—Methods to Determine the Biodegradability of
Surfactants) requires 80% of the mixture to be degraded within 21 days if the product is to carry the
label ‘biodegradable’.
Sometimes, biodegradation can change materials such as phosphate compounds from a biologically
unavailable form into a form that can be taken up and used by organisms.
Phosphate detergents
When phosphate detergents are used, disposal of the wastewater is an issue. The breakdown of
phosphorus complexes in detergent wastewater (and other household products, as well as human
and industrial wastes that contain phosphates) creates freely available phosphates; these can
contribute to an oversupply of phosphate in waterways and cause an imbalance of the aquatic
ecosystem, with the following results:
• Excessive algal growth (sometimes in the form of algal blooms) can occur with the addition of
available phosphates to the freshwater system. Generally, the naturally low levels of phosphates
in our soils and waters limit the phosphates in the freshwater bodies of southern Australia.
Blooms of cyanobacteria (blue-green algae) may also be toxic. This toxicity may be acute (shortterm
severe) or chronic (longer-term low-level), and can be carcinogenic.
NOTE: Most algae are an important part of the ecosystem; only in excess are they a problem.
• Decomposer organisms that require oxygen may increase, which can deplete the amount of
oxygen dissolved in the water. Excessively large numbers of decomposers may reduce the oxygen
levels to the extent that other aquatic organisms die from lack of oxygen. Decomposer
populations grow in response to an increase in their food, such as detergent components and, in
the drier summer months, the dying excess algae.
Using biodegradable phosphate detergents is advantageous only if detergent wastewater is directed
to the sewage system and the treated effluent is re-used to grow plants. The South Australian
government plans to increase the reuse of treated effluent for irrigation on land. A well-managed
reuse program can have an overall beneficial effect on the environment.
Phosphate-free detergents
Disposal of phosphate-free detergent wastewater is also an environmental issue. As an alternative to
phosphates, manufacturers can use a builder, or combination of builders, including zeolites
(aluminosilicates), sodium citrate and nitrilotriacetate (NTA). Detergent wastewaters containing
alternative builders also have environmental impacts and must be treated by sewage treatment
works. Some of them (alkyl phenols) are oestrogen mimics that can have serious detrimental effects
on populations of aquatic animals, such as decreasing their ability to reproduce. Even after
treatment, the environmental impacts of some alternative builders remain.
Your obligations
The principal legislation addressing pollution in South Australia is the Environment Protection Act
1993 (the Act). In particular, section 25 imposes the general environmental duty on all persons
undertaking an activity that may pollute, to take all reasonable and practicable measures to prevent
or minimise any resulting environmental harm.
The Environment Protection (Water Quality) Policy 2003 (Water Quality Policy) offers the most
specific protection for the state’s waters. The Water Quality Policy prohibits the pollution of the
stormwater system and our natural waters. It has general obligations with which every person,
business and industry must comply, as well as specific obligations for particular activities. Failure to
comply with any of these obligations may result in a $300 fine, Environment Protection Order,
and/or prosecution.
Clause 17 (1) of the Water Quality Policy states that a person must not discharge or deposit a
pollutant listed in Part 1 of Schedule 4 of the Policy into any waters or onto land where it might enter
any waters. The pollutants listed in Schedule 4 Part 1 include:
• cleaning agents
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• detergents and their by-products
• washdown water from cleaning animals or animal enclosures
• washdown water from cleaning vehicles, plant or equipment
• washdown water from commercial or industrial premises or wharves.
For more information on the Water Quality Policy visit the EPA web site at www.epa.sa.gov.au, or
telephone (08) 8204 2004 (Freecall 1800 623 445 for country callers).
How can you help?
Biodegradable detergents cause problems if they enter our stormwater systems, streams, rivers and
ultimately the ocean.
No matter which detergent you use, always direct your wastewater to the sewer or use it to irrigate
your garden (without allowing any runoff).
Both phosphate and phosphate-free detergent wastewaters have negative impacts on our waterways,
whether or not they are biodegradable. Directing the wastewater to the sewer allows wastewater
treatment plants to remove up to 90% of phosphates.
Help the environment by making sure contaminated water does not pollute our stormwater system.
Follow the steps below and refer to the EPA’s Stormwater Pollution Prevention Code of Practice for the
Community and/or the Easy Ways to Cleaner Water fact sheet for more advice on how to do the right
thing.
• Wash your car on the lawn or take it to a commercial car wash that recycles its wastewater.
• Dry-sweep footpaths and driveways and place sweepings in the bin. If you have an SA Water
permit to wash down areas, make sure all of the water is contained and not allowed to run into
the street gutters and stormwater drains.
• Place an absorbent material, such as sand or kitty litter, on grease patches, then scrape it up
and place it in a bin.
• Do not hose down paths or driveways. Mop or scrub and direct the wastewater into the sewer as
you would when cleaning inside your house.
FURTHER INFORMATION
Legislation
Legislation may be viewed on the Internet at: www.parliament.sa.gov.au/dbsearch/legsearch.htm
Copies of legislation are available for purchase from:
Government Information Centre
Lands Titles Office, 101 Grenfell Street
Adelaide SA 5000
Telephone:
Internet:
13 23 24
shop.service.sa.gov.au
For general information please contact:
Environment Protection Authority
GPO Box 2607
Adelaide SA 5001
E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Telephone:
Facsimile:
Freecall (country):
Internet:
(08) 8204 2004
(08) 8204 9393
1800 623 445
www.epa.sa.gov.au
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