Treating wastewater (also known as sewage) is important for our environment and communities. It’s cleaning the water used in homes, industries and businesses, water that’s full of contaminants, pollutants and disease-causing pathogens.
Understanding how wastewater treatment works and why it matters will help us appreciate its role in public health, sustainable water use and natural ecosystems across Australia and beyond.
What is Wastewater?
Wastewater is any water that’s been used and contaminated by human activity. This includes water from sinks, toilets, washing machines, industrial facilities and even runoff from roads and storm drains. Once contaminated, this water isn’t safe to reuse or return to the environment without treatment.
Why is Wastewater Treatment Important?
Treating wastewater is important for:
Public Health
Wastewater contains bacteria, viruses, chemicals and other harmful substances that can cause serious diseases. Wastewater treatment systems remove these threats before the water is reused or released.
Environmental Harm
If untreated wastewater enters rivers, creeks, lakes or coastal waters, it can disrupt ecosystems, reduce oxygen levels, kill aquatic life and spread waterborne illnesses like cholera or typhoid.
Water Pollution
In drought-prone areas, polluted wastewater puts extra pressure on limited freshwater supplies. Proper treatment reduces pollution risks and helps conserve natural resources and reduce ecological damage.
Environmental Impact of Untreated Wastewater
Untreated wastewater has severe environmental impacts. It often contains:
- Organic matter that depletes oxygen in water
- Excess nutrients (nitrogen and phosphorus) cause algal blooms
- Pathogens that spread disease
- Heavy metals and toxic substances from industrial runoff
When released untreated, this contaminated water can poison aquatic life, damage plant growth, and affect water quality for nearby communities. In areas where recycled water is used for irrigation, cleaning, or even drinking, the risks multiply without proper treatment.
Wastewater Treatment Processes
Effective wastewater treatment involves several stages:
Screening
Removes large objects (e.g. sticks, wipes, stones) that can damage equipment or clog systems downstream.
Primary Treatment
Uses settlement tanks to separate solids from the wastewater. Heavier particles sink, while lighter materials float and are skimmed off.
Secondary Treatment
Biological processes break down organic matter using bacteria that consume and digest waste. This stage reduces biological contaminants significantly.
Tertiary Treatment
An additional stage that targets fine particles, nutrients and pathogens. It may involve filtration, UV disinfection or chemical treatment depending on the application.
Disposal or Reuse
Once treated, the water may be reused for irrigation or industrial processes or safely discharged into rivers, creeks or the ocean according to local environmental standards.
The approach will depend on the site, industry type and the quality of the incoming wastewater. If you need advice on wastewater system design or compliance, call our Sydney team on (02) 4954 0440 for expert guidance.
Why Industrial Wastewater Treatment Matters in NSW
Treating wastewater isn’t just a