Frequently asked questions
Q: What is the cost and what are the key dates?
The 20-year contract to design, build and operate the biosolids drying facility has a net present value of $76 million.
Following an EPA Works Approval Process and completion of design, construction commenced in Q3 2008 and the facility will be completed by late 2010.
Q: What is the biosolids drying facility?
The new biosolids facility will be a fully enclosed drying process that will turn the Barwon region’s wet biosolids into pellets.
These biosolids pellets will be used as a nutrient-rich farm fertiliser or fossil fuel replacement.
No taller than the existing water reclamation plant, it will allow Barwon Water to treat the region’s biosolids in a sustainable manner.
Q: What are the key benefits?
It will allow Barwon Water to build on the 40 per cent reduction in greenhouse gas emissions already achieved compared to lagoon-based drying. Fewer truck movements will further reduce greenhouse gas emissions by more than 300 tonnes per year.
Safer roads by reducing the number of truck movements by 1000 to and from Black Rock Water Reclamation Plant each year (a reduction of nearly 60 per cent).
Sustainable and beneficial reuse of all biosolids generated within Barwon Water’s region.
Increased employment: 30 full-time construction jobs, five full-time construction management and six full-time project management and design jobs.
Q: What are biosolids?
When sewage is treated, micro-organisms digest the sewage, breaking down the organic material. Two products are created – recycled water and biosolids.
Each week, five and a half kilograms of biosolids are created treating each household’s sewage. That is enough biosolids to fill Skilled Stadium to a depth of one metre every year (54,000 tonnes). Before drying, biosolids are 85 per cent water and look like mud.
Q: What will the biosolids drying facility do?
The facility will dry the biosolids to 10 per cent water content and form it into round pellets. It will produce pelletised biosolids, treated to T1 Grade under the EPA’s Guidelines for Environmental Management – Biosolids Land Application, April 2004.
Q: How will the drying facility work?
Wet biosolids from the Black Rock Water Reclamation Plant will travel by enclosed conveyor belt to the drying facility. The drying process begins by mixing wet biosolids with dry biosolids pellets. This helps the wet biosolids form into new pellets. The mixed biosolids are then raked across heated plates, drying and forming into biosolids pellets. As the pellets reach the end of a plate, they fall to a plate below, where the process continues.
Water vapour produced in the dryer is condensed back to water in the condenser, which uses recycled water as the cooling medium. This water is returned to the Black Rock Water Reclamation Plant.
When the pellets reach the bottom of the pelletiser, a conveyor belt is used to load them into a separation hopper. At this point, some of the pellets, particularly the smaller ones, are returned to the start of the process to be mixed with wet biosolids entering the facility. The remaining biosolids are fed into a cooler, which uses air to cool the pellets. Once cooled, the pellets move by an enclosed conveyor belt to a storage silo. From here, they are loaded into trucks and transported to the end-use location, such as broad-acre farms.
The fully enclosed process will not produce any odours at the Black Rock Water Reclamation Plant boundary, nor will there be any visible emissions.
The plant will use natural gas.
To view a detailed diagram of the process in a new browser window, please click here.
Q: Is the technology used elsewhere?
There are biosolids drying facilities using Keppel Segher thermal drying technology throughout the world including Antwerp, Brugge and Deurne Schijnpoort in Belgium, Dundee and Lossiemounth in Scotland, and Baltimore, Chicago, Atlanta and Kingston in the United States of America.
Q: What will the drying facility look like?
Feedback from community consultation was that the biosolids facility should be no taller than the existing Black Rock buildings. The drying facility will be fully enclosed in a building the same height as the Black Rock Water Reclamation Plant. The height of the building is determined by the size of the vertical rack of plates used to form biosolids pellets.
To view images (artists impressions) of the biosolids drying facility, please click here.
Q: Where do the biosolids come from?
Only biosolids generated from the Water Reclamation Plants within Barwon Water’s catchment area will be dried by the biosolids management facility.
To view a map of Barwon Water’s catchment area in a new browser window, please click here.
Q: Where will it be located?
Barwon Water owns 250 hectares of land, including 110 hectares zoned public use, service and utility at the Black Rock water reclamation plant.
The biosolids drying facility will be built on this land alongside the existing plant and be connected by a 200-metre-long enclosed conveyor belt.
Locating it next to the water reclamation plant allows access to recycled water, saving four million litres of precious drinking water daily, that would otherwise be required to cool the facility.
Q: Who is Plenary Environment?
Plenary Environment is a consortium of companies engaged and overseen by Plenary Group.
Plenary Group is an Australian owned independent infrastructure business with significant expertise in the development and operation of public infrastructure. Its focus is on the creation of quality community assets with long-lasting benefits. Australian owned, it has a strong and successful portfolio of public infrastructure projects including Casey Hospital, Police and Courts facilities in six South Australian regional towns and currently has the Melbourne Convention Centre and a Defence Department housing project under construction.
Q: What is Partnerships Victoria?
The Partnerships Victoria policy, introduced by the Victorian Government in 2000, provides the framework for provision of public infrastructure and related ancillary services through public-private partnerships.
Barwon Water used the Partnerships Victoria model to ensure value for money for residents and secure the expertise of the private sector.
The policy focuses on whole-of-life costing and full consideration of optimal risk allocation between the public and private sectors. There is a clear approach to value for money assessment and the public interest is protected by a formal public interest test. Transparency is achieved through the publication of the Project Summary and contractual documentation.
Partnerships Victoria aims to use the innovative skills and abilities of the private sector in a way that is most likely to deliver value for money and improved services to the community.
Q: Why is it being done as a PPP?
Infrastructure projects are procured under the PPP policy when the Government believes a PPP can provide the best value for money; where a piece of public infrastructure is delivered while also achieving a transfer of risk of construction and/or commercial risk to the private sector and to protect taxpayers.
Barwon Water clearly believed that a PPP approach was the best value for money option in this instance.
Q: Will there be any discharge into the ocean?
The biosolids drying facility will not issue any discharges into the ocean. The facility will use recycled water from the Black Rock Water Reclamation Plant and will return this back to the plant.
Q: Will there be fumes and emissions?
Barwon Water has imposed strict contractual standards with respect to fumes and emissions, both in terms of levels and visibility of any plumes.
Plenary Environment has carefully designed the facility and treatment equipment to achieve these standards and ensure that emissions are well within safety limits.
Furthermore, the EPA Works Approval applies strict standards and conditions with respect to fumes and emissions.