Liquid waste management at Williamtown

In sensitive environments, it is critical for a builder to ensure that there is no risk of construction chemicals from finishing trades, such as painters, plasterers and tilers, being discharged or leaching into the ground or surrounding waterways. GeoSentinel’s Washbox — a self-contained water filtration and recycling system for liquid waste on construction sites — is one way to ensure such compliance is achieved.

Lendlease has used Washbox since 2006 on large, critical and sensitive building projects all around Australia, including the Magnetic Island and Hayman Island Resort upgrades on the Great Barrier Reef. So when the company was awarded the New Air Combat Capability (NACC) Project at the Royal Australian Air Force (RAAF) Base Williamtown, it contacted GeoSentinel.

The RAAF Base Williamtown, along with most other RAAF bases in Australia, has been caught up in an environmental contamination disaster. Since the 1970s, the Air Force’s emergency response firefighters have been training with firefighting foams known as aqueous film-forming foams (AFFF). AFFF, used to put out liquid fuel fires (such as an aircraft fire), contains chemicals known as per- and poly-fluoroalkyl substances (PFAS). During training exercises AFFF is sprayed into the environment and is now known to have leached into waterways, groundwater and the soil at dozens of sites across the country, include Williamtown. Studies have shown a probable link between PFAS and cancer, and there is now a major clean-up operation underway in these areas.

During construction projects, finishing trades need to wash various types of chemical solutions from their tools. These include paints, filling and patching compounds, adhesives and bonding agents, plaster and grout. These solutions contain solvents and chemicals that can change the pH levels in the environment, and suspended and dissolved solids that pollute the water. Though it is illegal to discharge liquid waste to ground, typical tool washing practices on some construction sites allow for the possibility of this occurring.

So when it came time to begin work on the Williamtown NAAC Project, Lendlease needed to ensure that liquid waste was handled correctly — and decided the best way to ensure compliance was to provide all the trades on site with access to Washbox. With the closed-loop Washbox system, all liquid trade waste is captured and turned into a solid that can be easily recycled. Washbox also recycles all the wash water after the waste is removed, so no liquids are discharged into the environment.

The Williamtown NACC Project consists of a number of buildings being constructed over a large area. GeoSentinel provided the project with a total of four Washboxes to service the various locations and finishing trades over a 76-week period. The Washboxes are hired to coincide with the ramp-up of finishing trades on site. As such, the first Washbox was delivered in early 2017, with two additional Washboxes scheduled to follow and a fourth once construction of the final building is underway. By coordinating the Washbox delivery in this way, the right tool washing capacity can be delivered efficiently to the right locations at the right times to meet the site operational and budget requirements.

Each Washbox can provide tool washing for around 40 finishing trades and in full use will save approximately 350,000 litres of water per year. As the Washbox does not release any of this liquid, it also prevents 350,000 litres of contaminated water from being discharged to the environment.

The project is not yet complete, but with four Washboxes on site, Lendlease is due to save more than one million litres of contaminated water from being discharged to the environment.