As part of a $26 million upgrade to ensure SA Water’s continued compliance with Australian drinking water standards, the utility installed an ultraviolet (UV) disinfection system for the drinking water at its Happy Valley water treatment plant, which keeps pathogens away and protects South Australia’s drinking water for over six months.
The largest drinking water ultraviolet (UV) disinfection system manufactured by Xylem in the Southern Hemisphere was commissioned in December 2021 and retrofitted at SA Water’s Happy Valley water treatment plant.
Four reactors with 624 UV lamps combined allow the system to instantly treat up to 600ml of water per day – designed with additional treatment capacity to maintain network flexibility and support changes in demand.
Senior Director of SA Water, Capital Delivery, Peter Seltsikas, said secondary disinfection with UV light would provide an additional layer of water quality protection against potentially harmful pathogens.
“Our new UV disinfection system in Happy Valley is another line of defense protecting the quality and safety of our largest drinking water supply in metropolitan Adelaide, while enabling kayaking and fishing in the adjacent reservoir” , Mr. Seltsikas said.
Pathogens come in a variety of forms and can be found naturally in water sources. The watershed that feeds Happy Valley Reservoir, via Mount Bold Reservoir, is large and covers the Mount Lofty Ranges.
“From a water quality perspective, this particular watershed is challenging given the presence of agriculture, so there is an ever-present risk of pathogens, such as cryptosporidium, entering our reservoirs. “said Mr. Seltsikas.
“To manage these risks, our Happy Valley wastewater treatment plant adopts a series of conventional treatment processes including coagulation, flocculation and filtration to trap and remove dissolved organics or other solid particles.”
720w" sizes="(max-width: 720px) 100vw, 720px" data-src="https://utilitymagazine.com.au/wp-content/uploads/2022/07/IMG_1579.jpg"/>One of the most energy efficient UV systems
Disinfection of water with chlorine occurs after filtration, to destroy microorganisms that may not have been captured, however cryptosporidium can be resistant to chlorine and escape treatment.
When pathogens such as cryptosporidium and giardia are exposed to high power UV light and absorb it, they destroy their structures and inactivate the cellular function of microorganisms.
Each reactor has 13 independent rows of 12 UV lamps, which work automatically and are able to switch off depending on the instantaneous treated flow and the quality of the incoming water.
“The lamps are powered by the latest electronic ballast technology – regulating lamp power from 50 to 100% – and exploit a sophisticated UV intensity sensor which significantly reduces energy consumption.
“These two features make it one of the most energy efficient UV systems, and when combined with our solar panel in Happy Valley capable of producing over 17,000 MWh of energy per year to help power the larger plant, ensures that we meet the system’s energy needs and operate it in a sustainable manner,” Mr. Seltsikas said.
720w" sizes="(max-width: 720px) 100vw, 720px" data-src="https://utilitymagazine.com.au/wp-content/uploads/2022/07/IMG_1559.jpg"/>Project on schedule despite supply chain challenges
Over 200 people worked on the project through SA Water and its construction partner, joint venture John Holland Guidera O’Connor, with 60 full-time staff working on the site at the peak of construction.
Mr Seltsikas said the team’s agility and innovation were at the forefront amid global shipping delays in 2021. “While the impact of the Suez Canal incident last year caused delays in the global supply chain, including with our UV system en route inside a shipping container, we initiated rapid design changes to our project and condensed the construction schedule for maintain our delivery schedule,” Mr. Seltsikas said.
“Our team reviewed the design of the inlet conduit, which required cutting a new weir into the existing wall, and the initial design included the manual demolition of concrete and a significant amount of structural steelwork.
“Harnessing creative thinking, we used a robotic saw to remove concrete more efficiently and cast a large concrete beam, eliminating the need to install steel to structurally support the new spillway.
“It was imperative that we stay on schedule despite the delay in receiving the infrastructure, and these design variations removed six weeks of work from the schedule to ensure we could complete the project on time and on budget.”
ABOUT HIS WATER
At SA Water, we provide our state’s most important and essential service – the delivery of safe, clean water. and reliable sewage services. We are a company owned by the people of South Australia, and we are committed to providing our 1.7 million customers with world-class water services that represent excellent assess. We invest approximately $300 million annually in maintaining and enhancing our statewide network to ensure it is continues to play a vital role in the social and economic development of South Australia. For more information, visit sawater.com.au
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