Sydney Water has recently announced that the upgrade of the Warriewood Wastewater Treatment Plant has been completed. The upgrade, costing $34.5 million and carried out over two years, means that the plant can manage the projected population growth in the catchment area for the next 18 years, until 2031.
The project has responded to concerns going back a number of years about wastewater overflows on Warriewood Beach, in particular.
The Warriewood plant is near Pittwater Road at Warriewood. It uses an activated sludge process to produce 16 megalitres a day of high quality effluent, which, following disinfection with UV radiation, is discharged into the nearby ocean at Turrimetta Head. Unfortunately, the best swell conditions for Warriewood’s surf southerlies that come along with low pressure systems and high rainfall are also the best conditions for causing an overflow at the Warriewood plant.
Local surfers and beachgoers have been advocating for years for an upgrade to the Warriewood plant to reduce the number of overflows. It got to the stage where locals gave Turrimetta Head a new, less appealing name of “Poo Point”. The Surfrider Foundation in particular has been very active in highlighting the effluent pollution around Turrimetta Head and Warriewood beach, and with the completion of this upgrade, have successfully cleaned up the last place in Sydney where effluent is discharged on this scale.
Better capacity means more reliability
The Warriewood plant catchment area is about 25 square kilometres, and includes the northern beaches suburbs from Palm Beach in the north to North Narrabeen in the south and Terrey Hills, Frenchs Forest and Duffys Forest to the west. Before the upgrade, the Warriewood plant served about 63,000 people.
In good news for Northern beaches plumbers, builders and other tradies, the number of residents in the Warriewood area is set to increase by more than 17% by 2031. But for a wastewater plant operating at capacity, the decision was made to increase the capacity of the plant to accommodate the increase. This was done by installing two new clarifier tanks at the plant, as well as upgrading electrical systems and equipment. These changes improve the efficiency and capacity of the plant, which will mean less frequent wet weather overflows.
Importantly, the upgrades also mean the plant is still compliant with its Environmental Protection Licence requirements. Until the upgrade, the plant was operating at full capacity, which meant there was no ability to both carry out maintenance and meet EPL requirements. With the extra capacity provided by the upgrade, maintenance can be carried out, which means better operational reliability.
Upgrades across the sewer network
The construction phase of the project began in July 2011, but the project itself began well before that. Sydney Water undertook an environmental impact assessment and asked for public submissions on the project. As a result of submissions, some key parts of the project were changed, such as the location of the access road and the rotary drum thickeners.
As well as this particular upgrade, the Warriewood Wastewater Treatment Plant has done other work to mitigate plant odours affecting developments around the plant. The plant had a history of complaints about odours, but with a further $14 million spent in 2011 on odour mitigation works, that should be a thing of the past.
Both upgrades are part of a bigger project by Sydney Water, which has committed to reducing the number of sewer overflows across the entire 23,000 kilometres of sewers it is responsible for. To do this, Sydney Water is spending $560 million over four years. And that’s certainly good news for regular users of Warriewood Beach and the waves around Turimetta Head.