Recycled water

Lake water

The UniSC Sunshine Coast campus is the low point in the wider Sippy Downs catchment area. At the low point of the campus are two lakes with a capacity for 130,000,000 litres of water. The lake water is part of an integrated catchment system that directs stormwater, rain and wastewater run-off through a system of swales and creeks before being collected for storage in two lakes onsite.

Untreated lake water is used for irrigation of campus fields. On-site water treatment removes solids and modifies the lake water to produce potable standard water for use as make-up water for the pools, central energy plant and the cooling towers which are a part of the campus air-conditioning system. The University pool also uses an efficient electronic chlorinator.

Since this project has been implemented, the University has saved over 20,000 litres of mains water used per day, which also significantly reduces the cost.

Rainwater and wastewater treatment

The plant draws water from the lake via a low velocity screened intake arrangement, ensuring no flora or fauna is detrimentally affected by the water extraction process. This process greatly reduces the amount of potable water being sourced from mains with the dual benefit of lowering both emissions and water bills.

The water treatment plant consists of feed water pumps, holding tanks and various filtration components - complete with a filter backwash cycle. The capacity of the water treatment plant is sized for a peak flow of 15kL/hr to the cooling towers, and an overall processing capacity of 10kL per/hr. These values were selected to deliver the full amount of cooling tower makeup water during high cooling load requirements.

The treatment plant serving the cooling towers in the central energy plant (CEP) consists of the following elements:

• A foot valve at the centre of the lake and underground intake pipework to the pumps at the CEP
• Raw and filtered water storage tanks
• Glass media filtration system filtering water to 4 microns
• An ultra-filtration system with 0.03 µm nominal pore diameter for removal of bacteria, viruses, and particulates including colloids
• Suitable capacity for the use of the plant and future demand
• Full PLC control system
• Integration into the BMS

The plant is maintained and monitored daily and undergoes monthly water quality testing for biological contamination.

Lake water treatment allows more than 90% of the annual cooling tower, CEP and pool makeup water to be sourced from the lake in non-drought years. This was measured at nearly 24,500 kL in 2020.

Rainwater tanks

The UniSC Moreton Bay campus captures and reuses rainwater from several tanks with a total capacity of 435,000 litres. Once the rainwater is harvested, it is recycled through the buildings for use in toilets and urinals.

The UniSC Sunshine Coast campus captures rainwater from the E Block in a 5,000 litre underground tank. The water is used in E Block's grey water system for toilets and urinals.

Recycled vs Mains

Given the mains water consumption across UniSC campuses in 2023 of 28,506 kL at Sunshine Coast and approximately 10,035 kL at Moreton Bay and the harvested water consumption of approximately 35,039 kL at Sunshine Coast and 1,173 kL at Moreton Bay, the percentage of recycled water being used was over 55 percent at Sunshine Coast and over 10 percent at Moreton Bay.

Water quality and conservation

Storm water management and aquatic ecosystems

There is a storm water management system of lakes, swales and settling ponds on campus to protect the Mooloolah River National Park's waterways from physical, chemical and biological alterations that can lead to high nutrient levels and sediment run-off.

Water monitoring and systems

UniSC conducts regular surveys to locate water leaks on campus and has implemented audit and flow test of all taps and fittings and the installation of water saving devices and efficient isolation points for ongoing plumbing works on campus.

Hot water at the University’s research centre on K'gari is provided entirely by solar hot water systems.

Water refill campus initiative

UniSC Sunshine Coast and Moreton Bay are water refill campuses providing a variety of alternative options to purchasing commercial bottled water on campus.

Water conservation

UniSC has design standards that mandate the use of Australian Water Efficiency Labelling and Standards (WELS) rated fixtures and fittings (6-star taps, 4-star dual flush toilets, 6-star low flush urinals and showers with a maximum resultant flow of 9L per minute) to ensure water use is minimised. Signage is posted in public and office toilets to encourage staff, students and visitors to turn off the taps and report any leaks.