News from University of California, Irvine

Navigating ocean waters

Beyond her research on water quality and desalination, UC Irvine environmental engineer Sunny Jiang is deeply concerned about the broader implications of water reuse, especially how it’s gradually increasing antibiotic resistance in the ecosystem.

Although she was born in China, Sunny Jiang spent her formative years in Florida, where her love of the outdoors led her to spend as much time as possible in the ocean, even learning how to scuba dive.

Now a professor of both civil and environmental engineering and ecology and evolutionary biology at UC Irvine, Jiang – who holds a Ph.D. in marine science – has dedicated her career to understanding the delicate balance between human activities and coastal ecosystems.

Her journey began with a deep-rooted passion for environmental sustainability and a keen interest in recreational water pollution. “I was an active person; I liked surfing and swimming and running on the beach,” she recalls. “So I was interested in environmental ecosystems and the presence of pollution in recreational water areas.”

As a graduate student more than 20 years ago, Jiang and her fellow researchers spent time in the Florida Keys measuring the impact of wastewater on the ocean. “At the time, there were a lot of coral reefs,” she says. “We dove down to them and took samples to show how wastewater percolated up to the reef.”

To measure this, Jiang says, she dosed clean toilet water with a harmless visual marker and continuously flushed it into the groundwater. Then her team worked with the U.S. Geological Survey to drill holes on the sea floor so they could access the groundwater and see how much of the dyed toilet water was present.

Upon her arrival at UC Irvine in the late 1990s, Jiang continued unraveling the complexities of coastal water quality, particularly in areas like Huntington Beach, which saw its beaches shut down for three months in the summer of 1999 because of wastewater pollution.

“That was a huge economic loss,” she recalls. “I did a lot of work trying to understand the coastal pollution from both the storm channels and occasional wastewater discharge.”

Over the past two decades at UC Irvine, Jiang says, she has witnessed significant advancements in coastal water management, especially by the Orange County Sanitation District. It now jointly operates – with the Orange County Water District – the county’s Groundwater Replenishment System, which purifies up to 130 million gallons of wastewater coming from 2.5 million residents each day. It’s both the world’s largest wastewater recycling plant and the first county water agency in the U.S. to recycle every ounce of its wastewater.

One area of particular interest for Jiang is desalination, a controversial yet increasingly attractive process for addressing water scarcity in drought-prone states such as California.

“It’s definitely a viable option,” she says, adding that desalination technology has improved over the years so that neither its ocean water intake nor its high-salinity output poses the threat to small ocean creatures anymore that made it unpopular among activists and some marine biologists. “The cost is mostly because of permitting and fighting the lawsuits from certain environmental groups,” Jiang explains, “but not because of the infrastructure.”

Beyond her research on water quality and desalination, she is deeply concerned about the broader implications of water reuse, especially how it’s gradually increasing antibiotic resistance in the ecosystem. “I’m worried about not just the direct contact from recreational activity, but also transfer up the food chain with antibiotics,” Jiang emphasizes. “In the next 20 to 50 years, antibiotic-resistant infection risk is going to be a major issue.”

For her, the nexus between environmental health and human well-being is paradoxical. “My work is to understand the interaction among the environment, water and human health,” Jiang says. “The connection between the environment and human health is an opportunity, but it’s also a threat.”

“I support water reuse,” she continues, “but we need to plan for antibiotic-resistant bacteria going through the food chain. These are the things we need to think about for the long term so we don’t get ourselves into trouble.”

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