The Bryn Estyn water treatment plant provides about 60 per cent of Hobart’s water supply system needs every year. Originally built in 1962, an upgrade is needed to ensure the plant can continue to provide high-quality drinking water and meet projected demand for years to come.
VEC is building the BAC (biological activated carbon) filter structure, essentially a very large filtration tank and one of many involved with the water filtration process. The first concrete pour happened in mid-August.
“The blinding was the first layer to go down before we started building the structure itself. This pour used 231m3 of concrete,” said Project Manager Nick Moore.
“The next step is the base slab, which will be 500mm thick and poured in two halves. Then we build a big rectangular water tank made up of several cells.”
The overall structure of the water tank is 43.3m long, 22.3m wide and 6.2m high. The tank is comprised of eight cells, each of which is 10.4m long, 8.4m wide and 6.2m high.
Nick said because the tank is so big, the base slab will be done in two parts, with a dowelled construction joint between the two parts to allow for movement within the structure. These two parts will use a combined total of 472m3 of concrete.
The entire base slab will be poured onsite, requiring installation of formwork and reinforcement, and placement of concrete.
“The walls for the tank will be raised off that base slab, and prior to the project’s completion, the tank will be filled with water to make sure none of the cells leak,” Nick said.
This project is one of many work packages associated with the water treatment system upgrade and has a critical connection with other parts of the upgrade project.
“Given the multifaceted nature of water treatment plants, each stage or element of the plant is critical for the commissioning and operation of the plant once complete,” Nick said.
The complete upgrade of the Bryn Estyn plant will take roughly three years, and once testing and commissioning is completed, TasWater expects it to be operational in 2023.