Sewerage

Sewerage

• Overview
• Actions

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.

Sewage itself is not litter, however, given that treated effluent eventually goes into local water sources or the sea (after wastewater treatment), any residual items remaining in sewage can potentially become a type of litter. This litter 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.

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[2][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:

Air

Water

Mechanical

Biological

References

1. ^ Campanale, C, Massarelli, C, Savino, I, Locaputo, V & Uricchio, VF (13 February 2020), 'A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health', International Journal of Environmental Research and Public Health. [online], vol. 17, no. 4, p. 1212. Available at: https://www.mdpi.com/1660-4601/17/4/1212 [Accessed 22 April 2025].
2. ^ Young, N (2017), 'How does plastic end up in the ocean?', Greenpeace. [online] Available at: https://www.greenpeace.org/new-zealand/story/how-does-plastic-end-up-in-the-ocean/.

Last updated: 22 April 2025