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People flushing inappropriate items down the toilet Wastewater from washing machines containing microplastics People pouring waste into sinks and stormwater drains People littering or dumping items in manholes

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This waste pollution may result from:

  • people flushing inappropriate items down the toilet, such as wipes, kitchen paper, nappies and unused medications
  • wastewater from washing machines containing microplastics, such as from polyester clothes
  • people pouring waste into sinks and stormwater drains, such as toxic items, oils and cooking fats
  • people littering or dumping (sometime very large) items in manholes.

The sewerage system is generally taken to comprise:

  • the sewage collection network (sewerage pipes leading from private, commercial and public premises)
  • sewage pumping stations
  • inspection points
  • sewage treatment and re-use or disposal processes.

Detailed information can be found here.

Although there is strict legislation covering sewage in Queensland, damage can still result from the improper disposal of materials down toilets, including plastic bags, sanitary items and chemicals. Small plastic items that are flushed into the sewerage system can get caught in pumps and create blockages, causing overflows and contamination. Illegal dumping down manholes can also damage sewerage infrastructure.

As in so many other areas, the presence of microplastics and their flow through sewerage plants is only just being investigated. Microbeads (tiny pieces of plastic) are used as ingredients in many cosmetic products. Many microbeads are too small to be filtered out by wastewater plants and end up flowing into rivers and oceans[1].

Oils and fats in the sewerage system can combine to form ‘fatbergs’. These are difficult and expensive to manage, and can cause substantial damage to infrastructure, resulting in system closure and further expense.

Waste pollution in the sewerage system moves through the environment via four pathways:


  1. ^ Young, N (2017), 'How does plastic end up in the ocean?', Greenpeace. [online] Available at:

Last updated: 10 May 2021

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2021) Sewerage, WetlandInfo website, accessed 18 March 2024. Available at:

Queensland Government
WetlandInfo   —   Department of Environment, Science and Innovation