What is this project about?
Hunter Water is seeking planning approval for the possible construction of a temporary desalination plant at Belmont. This is our insurance policy in case of unprecedented drought conditions.
What is a 'temporary' desalination plant?
Hunter Water doesn’t intend to make the desalination
plant a permanent source of water. It is intended as an emergency measure
only, and the plant would be decommissioned when water storage levels returned
to 50 per cent.
What will the project cost?
When will it be built?
The temporary desalination plant is only to be built if our water supply reaches critical levels of 35 per cent. Planning for the temporary desalination plant is an emergency measure, rather than part of Hunter Water’s long-term water resource planning. Hunter Water is planning to formally submit the application for development approval in April 2019.
Why are you waiting to build it?
The odds of switching on the plant are very low but we won’t take the chance of running out of water because planning approvals were not in place. Gaining approvals now means we’re ready for the worst and can construct the plant relatively quickly should it be required.By saving water in our own system, and working in partnership with industry and the community to reduce demand, we’re allowing time for new technologies to emerge which will make for a smarter, more sustainable water future.
Why has Belmont been chosen as the location?
Hunter Water undertook a multi-site analysis to determine the best place to build a temporary desalination plant. The analysis included Hunter Water land at Belmont Waste Water Treatment Works, the former Stockton Waste Water Treatment Works, Eraring Power Station and Newstan Colliery. The analysis looked at costs, power supply, and environmental and community impacts.
Hunter Water’s land at Belmont was selected as the best option, given existing ownership of the land, construction costs and lower community disruption and impacts. The brine (remaining salt water from the desalination process) could also be returned via the existing outfall at the Waste Water Treatment Works.
How much drinking water will it produce?
The proposed temporary desalination plant could produce up to 15
megalitres per day. This would be enough to slow the depletion of water from
our main water sources but would still represent only a small proportion of our
overall water supply.
How does desalination work?
Desalination is the process of removing dissolved salts and other particles from seawater.
1. Pre-treatment – Seawater filters through beach sand into perforated horizontal pipes and flows into a central collection well. Water is pumped from the well into the plant where coarse filters are used to remove larger particles. The seawater is then filtered through ultra-fine membranes to remove smaller particles.
2. Reverse osmosis – The cleaner seawater is then forced at high pressure through thousands of reverse osmosis membranes, which act as very fine filters, to remove dissolved salts and other particles. Fresh water is extracted and seawater concentrate is left behind. Approximately 42 per cent of the seawater becomes drinking water.
3. Final Treatment – The fresh water is treated to meet Australian Drinking Water Guidelines and fluoride is added to protect teeth. The drinking water then travels through pipelines to join the Hunter Water supply network at two locations, Belmont and Jewells.
4. Seawater concentrate – The remaining seawater concentrate is about twice as salty and about one degree warmer than the ocean. It would be pumped to the existing Belmont Wastewater Treatment Works ocean outfall, where it would be returned, along with wastewater effluent, through a large pipe that lies beneath the seabed. The effluent and seawater concentrate is dispersed using specially designed diffusers which return the seawater concentrate to normal salinity and temperature.
How much energy does desalination use?
Desalination does use more energy than sourcing water using traditional methods, such as gravity feeding water out of a dam.
We should remember that desalinated water is not reliant on rainfall so in a drought it would be our emergency measure.
It takes the same amount of power to run a modern fridge for one day as it does to produce enough desalinated water for the daily use of a family of four.
What happens to the salt from seawater?
During the desalination process, freshwater is extracted from seawater and brine is returned to the environment.Desalination plants need to meet stringent environmental protection criteria. They’re designed to have minimal impact on the surrounding environment.
What is the impact on the environment?
Hunter Water places a high priority on minimising any environmental impacts - both on land and in the water.
The preliminary environmental assessment for the temporary desalination plant is currently on public exhibition on the Department of Planning’s Major Projects website.An Environmental Impact Study is required as part of planning approval and work on this has now begun. The study will be made publicly available and it will help inform our application for planning approval to be made in 2019.
How does the desalinated water taste?
water sourced from a dam and treated at a water treatment plant, water from a desalination plant would be treated to meet Australian Drinking Water
Guidelines, which include criteria for the aesthetic quality of drinking water
in addition to criteria for the protection of health.