Waste Water Facts: Everything You Need To Know
Australia is a water-scarce country, yet its population uses around 16,500 gigalitres of water— enough to fill Sydney Harbour 33 times. Many Aussies rarely consider their water source and where wastewater goes after use.
The typical Australian consumes 82,000 litres of fresh water. Utilities lose around 80-110 litres of water per day before it reaches your home. At the same time, people carry out their daily routines and drain infinite litres of water into the sewer pipes. Wastewater management is essential for the sustainable use of the country’s water sources.
Read on to discover key facts about wastewater, including how it’s safely treated and managed to create thriving, liveable, and sustainable cities across Australia.
What is Wastewater and Its Types?
Wastewater is any water discharged by residential and non-residential customers through the sewerage system. It’s mostly contaminated or polluted after use from domestic, industrial, and agricultural operations and runoffs.
So, how can wastewater be reused? Wastewater undergoes multiple processes in sewage treatment plants depending on its type, categorised into:
- Greywater: Wastewater generated from non-toilet sources within an infrastructure, such as showers, sinks, bathtubs, and laundry machines. An average person produces 100 litres of greywater daily, equivalent to 146,000 litres a small family uses annually. This is typically treated and reused for non-potable purposes like flushing toilets or irrigations.
- Blackwater: Wastewater originated from urinals and toilets, making it highly contaminated. This often requires advanced treatments to eliminate impurities and pathogens before being discharged into the environment. For instance, a boater’s one-weekend discharge of untreated sewage has a similar bacterial load produced by treated sewage from 10,000 people!
- Stormwater: Rainwater penetrates impervious surfaces such as roads, parking lots, and rooftops. This often flushes pollutants like oil, grease, and debris that flow and pollute ponds, sewage lagoons, and groundwater basins.
In Sydney, about 90% of wastewater after first treatment ends up in the ocean, discharged four km deep in outfall pipes at North Head, Malabar, and Bondi. Other regions still use underground sewerage systems to expel wastewater into water bodies. That’s why optimal collection, processing, and treatment are necessary to recover these valuable water resources.
Sources of Wastewater in Australia
Adequate wastewater treatment protects public health and drives flourishing aquatic and terrestrial life. Consistently doing so is often quite challenging. The good news is that anyone can proactively take steps to limit or properly manage wastewater from its existing sources.
Domestic Wastewater
Residential spaces generate a substantial amount of wastewater, including sewage and greywater. In 2021-22, around 1,974 gigalitres of sewage were flushed in sewers, mostly from households. That’s enough to fill over 700,000 average-sized home swimming pools!
Sewage, however, undergoes tertiary and advanced treatments before it can be reused for non-potable purposes. Household greywater contains fewer contaminants than sewage, yet it still requires primary and secondary treatments for safe reuse and discharge.
Industrial and Commerical Wastewater
Australia’s manufacturing, food, and service industries generated two gigalitres of wastewater in 2021-22. Chemicals, grease, and oil-based waste are common in business wastewater, often treated to neutralise hazard levels and reused for industrial and agricultural use.
Meanwhile, most commercial trade wastewater from retail food businesses contains organic materials and grease traps that can be composted. Other industries, like mining operations, discharge highly toxic wastewater requiring specialised handling and treatment.
Agricultural Wastewater and Runoff
Australia’s agricultural sectors are a primary chemical runoff and animal waste source. Fertilisers, pesticides, and herbicides often leach into waterways and contaminate them. On a good note, the country treats about 236 gigalitres of wastewater, mainly recycled for irrigation. Processed agricultural wastewater also creates biosolids, which are nutrient-rich soil compost.
Key Wastewater Statistics in Australia
Australia’s water facilities received 2,240 gigalitres of wastewater in 2021-22. About three-quarters of it was returned to the environment, while only 276 gigalitres were reused. While there’s no exact breakdown of its sources, a huge chunk comes from household areas.
How does Australia manage its collected wastewater?
The country has 726 operational sewage treatment plants. About 54% of the country’s wastewater undergo tertiary levels, 28% to secondary levels, and 18% to primary levels. These advanced processes purify and neutralise wastewater’s hazardous components.
In 2021-22, treatment plants discharged about 1,803 gigalitres of treated wastewater into the ocean and water bodies. About 236 gigalitres were recycled, yet an unaccounted untreated volume is still released daily in the country’s waterways.
While wastewater treatment rates increase, so do urban areas requiring excessive water resources. What’s more, some remote regions may still lack adequate treatment facilities. Smarter use and planning are critical to maintaining sustainable water supplies.
Environmental Impact of Wastewater
With a huge volume of wastewater ending up in the waterbodies and oceans, how does it affect the surroundings? Let’s look at the environmental impact of the country’s wastewater.
Impact on Marine Ecosystems
When discharged into marine environments, untreated wastewater may harm aquatic ecosystems. For example, wastewater containing chemicals and heavy metals contaminates seawater and smothers coral reefs, making it unsuitable for most marine life. On a larger scale, it impacts recreational activities, tourism, and public health within coastal areas.
Eutrophication in Waterways
Australia has 187 coastal wastewater outfalls. When nutrient-rich wastewater flushes out in these pipes, it can result in eutrophication, where nutrients slowly accumulate in water bodies.
Put simply, fertilisers containing high levels of nitrogen and phosphorus accumulate in waterways, promoting the rapid growth of algae. Once these algae overpopulate and die, they deplete water quality and oxygen, potentially suffocating fish and other aquatic life.
Climate Impact and Methane Emissions
Australia emitted 12.49 million tonnes of greenhouse emissions in 2022, 2% of which came from wastewater and organic matter in landfills. That’s 240,000 tonnes of CO2e, equivalent to emissions from 24 million gallons of gasoline consumed!
That’s why reducing wastewater is a factor in mitigating climate change and protecting the country’s vibrant nature. Enhancing landfill management, upgrading treatment facilities, and minimising sewage leaks are some actionable strategies for reducing wastewater’s methane emissions.
Waste Water Treatment and Management in Australia
While wastewater can be a valuable resource, this depends on how it can be treated to meet safety and quality standards. Robust wastewater treatment infrastructure employs a multi-stage approach to produce safe, hazard-free water through:
- Primary Treatment: Screen traps items as wastewater flows through, with heavier particles sinking. Scrapers collect sludges settling and grease or oil (scum) floating, which will be treated to produce biosolids.
- Secondary Treatment: Facilities add microorganisms (activated sludge) to break down nutrients and organics. Once done, the activated sludge is turned into biosolids.
- Tertiary Treatment: Chlorine or ultraviolet light disinfects wastewater, eliminating remaining microorganisms.
- Advanced Treatment: Some facilities use microfiltration, ultrafiltration, or reverse osmosis to remove traces of nutrients, chemicals, and dissolved salts in the water.
What usually happens to treated wastewater? After undergoing rigorous treatment stages, this can be used to irrigate agricultural lands. Industries like manufacturing and construction often use treated water for cooling, cleaning, and other vital operations. Recycled wastewater even refreshes urban landscapes, including parks and gardens.
One prime example of successful wastewater recycling is the Western Corridor Project in Queensland. With the region’s sparse water supply, the project desalinated and purified wastewater with a capacity of 232 million litres per day. It recycles water to supply urban, agricultural, and industrial processes.
On the other hand, Adelaide’s GAP (Glenelg to Adelaide Pipeline) Project is also a remarkable water recycling scheme. It recycled 25 billion litres of high-quality treated wastewater, which has sustained 163 hectares of city parks and the pristine turf of Karen Rolton Oval.
Common Challenges in Waste Water Management
While wastewater treatment facilities are still yet to reach many remote communities, established institutions are trying to fix common issues in wastewater management, such as:
Aging Infrastructure
Most Australian regions’ sewage systems and treatment facilities were built decades ago. These aging infrastructures are prone to breakdowns and leaks, reducing treatment effectiveness. Such structural instability is likely to fall short of current demands and standards.
Industrial Pollution
Industrial wastewater often contains toxic contaminants, which presents unique challenges for most treatment facilities. Most municipal treatment plants cannot remove excessive levels of chemicals in wastewater. For example, an advanced oxidation process can treat wastewater containing pesticides or pharmaceuticals that are difficult to remove with conventional means.
Public Awareness and Education
Improper waste management poses severe environmental and health risks that many people may not fully understand. One key example is Sydney Water, revealing that 55% of its customers believe it’s okay to flush items other than human waste and toilet paper.
Ejecting more unwanted items into the sewage system hinders the effort to recycle more wastewater in Australia. Without community awareness and education, insufficient public involvement and support impedes sustainable wastewater practices.
Benefits of Effective Wastewater Management
While the initial goal of wastewater management is to avoid polluting waterways, it has lasting benefits. It recovers reusable water resources and keeps the environment pristine and attractive for animals to live and thrive. Recycled water also recirculates and adds to local water reserves.
How about its economic advantage? The country can substantially save water costs by reusing over 270 gigalitres of wastewater to supply, enough to irrigate about 224,000 acres of plantation! This could create more jobs, stimulating financial growth in regions facing water scarcity.
Beyond monetary gain, efficient wastewater treatment prevents the spread of waterborne diseases. Highly-treated wastewater replenishes groundwater, improving water quality for safe recreational activities, swimming, and non-potable and potable uses.
Frequently Asked Questions
How much wastewater is generated in Australia annually?
Australia’s water supply, sewerage, and drainage services (WSSDS) received 2,420 gigalitres of wastewater in 2021-22, almost a 12% increase from the previous year (2,168 gigalitres in 2020-21). This figure is set to spike as urbanisation becomes denser, generating excessive wastewater.
What are the main sources of wastewater pollution?
Wastewater becomes heavily polluted or contaminated depending on its main sources. It can originate from residential, commercial, industrial, and agricultural sectors. Industries using cocktails of heavy metals and chemicals are likely to generate highly toxic wastewater.
How is wastewater treated?
Wastewater treatment involves a multi-stage process. Its main steps include removing solid items, using chemicals to reduce turbidity, and adding microorganisms to break down organic matter. Disinfection using chlorine or UV light kills harmful pathogens to make it safe to use.
Can wastewater be reused safely?
Yes. Most treated wastewater is often used for non-potable purposes. After rigorous treatments, it can be used for urban landscaping, agricultural irrigation, and industrial operations. Recycling wastewater conserves water resources and reduces pressure on potable water supplies.
How can individuals help reduce wastewater pollution?
Individuals have vital roles in reducing wastewater pollution. While it’s almost impossible not to flush water into your sewage pipes, adopting water-saving practices can minimise it. Limit fertilisers and pesticides or avoid discharging chemicals to cut wastewater pollution. Be conscious of your water consumption and avoid unnecessary waste whenever possible.
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