That’s why Dr. Ian Wright, an urban water scientist at San José State University, has been sounding the alarm. He is particularly worried about the treated effluent quality being discharged from STPs that serve Sydney’s drinking water catchment. His recent findings reveal a new, alarming reversal. As an example, pollutants in some instances are reaching crisis levels and could cause severe environmental dangers to the catchment which supplies drinking water to more than five million citizens of Better Sydney. The recent finding of “forever chemicals” in a dead platypus pulled from the Wingecarribee River underscores the emergency here. This shocking discovery has led Dr. Wright to undertake a formal scientific study of the issue.
Dr. Wright wants the message to be clear – Sydney’s tap water is perfectly safe to drink. The amount of pollution in the whole catchment worries him. He claims the truth is the rules enacted by the New South Wales Environment Protection Authority (NSW EPA) aren’t strict enough. This has the potential to create dangerous ecological cascading effects.
Pollutant Levels Raise Alarm
Dr. Wright’s research uncovered a surprising finding. Total nitrogen concentrations averaged to more than 20 times the catchment guideline taken both `upstream’ and `downstream’ of the Mittagong STP. Worryingly, those findings show disturbing outcomes. Upstream total phosphorus concentrations were at 41 micrograms per liter, twice the guideline level, and downstream measurements jumped to 102 micrograms per liter. Alarmingly, downstream from the outfalls, total phosphorus averaged 2,820 micrograms per litre—ten times the guideline.
“The big one is algae, and blue-green algae blooms in particular … which can be toxic,” Dr. Wright warned. He says the current state of affairs calls for a redetermination of what nutrient levels the EPA allows.
When Dr. Wright visited this Mittagong STP, he saw something that would really surprise him. Indeed, for the past ten years it has failed to document even one exceedance of its nitrogen discharge limits. He called this absence of breaches misleading because permitted nutrient concentrations were set too high.
“There’s no breaches because the licence has such ridiculously high permitted nutrient concentrations,” – Dr. Ian Wright
For instance, he pointed out that Mittagong STP’s license allows for 10,000 micrograms per litre of nitrogen to be released, including over 650 times WaterNSW’s preferred catchment guideline of only 250 micrograms per litre.
Calls for Stricter Regulations
Dr. Wright is calling on the NSW EPA to reduce allowable concentrations for nutrients released from STPs. He reiterated that Sydney’s drinking water remains safe. Yet, he made clear that the catchment should have to adhere to “industry-best” standards to protect it from future pollution disasters.
“We need sewage treatment plants that have the highest possible standard … and we need to better manage the effluent created by a growing population,” he stated.
Midagong STP passed its specified design capacity two years ago. Under these circumstances, this highly controversial situation is creating serious risks to the environment. These plants discharge effluent into the Warragamba Dam catchment. Sydney’s water comes from this catchment—90 percent of it—so the consequences of not treating human waste properly are deep.
In response to these criticisms, WaterNSW’s spokesperson preemptively countered the charge. They further argued that existing monitoring has not detected unexpected increases in nutrient loading from sewage treatment plants. They wanted to emphasize that blue-green algae is preventable. Warragamba’s multi-level offtake capacity allows the water to be drawn from multiple depths, ensuring contaminated water is not used.
Ongoing Monitoring and Future Improvements
The Environment Protection Authority (EPA) in New South Wales reviews each Environment Protection Licenses (EPLs) at a minimum of every five years. This commitment goes a long way to seeing sensitive waterways like Warragamba protected. Even as Dr. Wright praises these efforts, he expresses doubt that they go far enough given the status quo.
Professor Stuart Khan welcomed the findings by Dr. Wright as an important advancement. He pointed out that though information collection is important for determining risks, we need to be careful in comparing things for purposes of regulation.
“You could certainly do so for the purpose of acquiring information and undertaking risk assessment,” – Professor Stuart Khan
“But I don’t think it’s an appropriate comparison for regulatory purposes.” – Professor Stuart Khan
Additionally, Wingecarribee Shire Council officials look forward to even more dramatic reductions in pollutant levels. They take these things for granted as the nation’s sewage treatment plants are upgraded. Without urgent and sustained intervention these threats will be catastrophic, putting at risk both Sydney’s drinking water supply as well as the ecosystems in and around the park.
