The Mallacoota Basin Cover is approaching a hectare in size and an awesome volume is contained within.
Covering water to reduce evaporation and algal bloom is not new. What is new is the use of membrane technology to create a structure that can self support above an area and provide constant protection. This structure was monitored for two years by CSIRO and tests show that 90% of evaporation is prevented at a minimum and that there was no algal blooms. For more information on these tests visit The CSIRO.
East Gippsland water were a client for five of these structures, all successful.
SuperSpan’s involvement began in 1995 when evaporation from channels was a major problem which could be rapidly alleviated by covering with cloth. Unfortunately water just wasn’t worth much and we presumed the designs we developed would hit the bin. That was until an email came from Kris Hunter at East Gippsland Water inquiring about shade over water. Through years of testing and analysis we can now claim success.
Bemm River was the first covered and records show that algal bloom ceased as soon as the cover was installed. Occasionally, from some storages the contents had to be dumped due to algal infestation and the difficulties of dealing with the toxicity. Not only does the cover reduce waste through evaporation control but also through contamination prevention.
We were approached by Melbourne Water to construct a 9 megalitre detention storage, basically a big septic tank complete with a serpentine of channels to control the flow of water. The project was completed on time and has been an unqualified success making available 9 meg of class A water every day.
Creating Pure Water
SuperSpan has developed a broad acre condensate, dew and rain harvester that can produce a minimum of 10 megalitres of fresh water annually for every hectare of operation.
A distillation cell which comprises a tensioned web forming a shallow box-like structure provided with an inverted V-sloped roof wherein moist air develops in the cell and water condenses on the lower surface for passing to collection. This cell is modular with multiple structures connected to extend over very large areas.
This is the first broad acre solar still. It utilises solar humidification technology on a grand scale. Solar stills of large size have been built but not at this scale of economy. The IP and prototypes are available to proof of concept standard. Our fully operational demonstration proto type is located at Flinders in Victoria.
The WaterCycler water harvester utilises the interconnection of groundwater and surface water systems to actually produce distilled water from the most turbid, saline or polluted of water resources. (volatiles not included). This greatly increases groundwater yield and value and is not contingent upon the transport economics of energy dependent technology.
Each hectare of WaterCycler produces approximately10 mg/L of distilled water per year in a saline hydro-geological environment. The present price for that water in that location being provided by other means is A$1500per mg/L but this is for raw agri water. Efficiency will vary with location.
With no energy costs at all once the structures are in place, each 100 sqm (10m x 10m) module costs A$3,000 envisaged with installation depending on the hydro-geological features of the site. Production on a large scale will bring price efficiencies.
The concept of distillation was conceived during construction of the above structure at Swifts Creek reservoir for East Gippsland Water. The cover is designed to prevent algal bloom and evaporation and is entirely successful at that. It also produces large amounts of condensate which was a little unexpected and it seemed obvious that if a better material and design was employed it would be possible to supply the town with distilled water rather than treated water from the basin.
A prototype was then constructed merely to prove the concept and it proved very successful producing water immediately upon installation. It was constructed using inexpensive materials which are not optimised for efficiency and there are many areas of refinement which are being pursued. The second prototype is currently being fabricated with CSIRO offering to run trials to assess water quantity and quality in a more formal manner than has been done.
Once completed it is envisaged that a large scale prototype (around half a hectare) will be built.
The large scale structure would be built using different materials but similar techniques to the SuperSpan structures which have been successful both domestically and internationally for 27 years.
The watercycler has a wide variety of possible uses ranging from land reclamation to creation of potable water from the sea. In order to reclaim land a solar pump could bring saline groundwater into the unit where the salt would be left as a by product with fresh water being the primary product. Over time this would aid in the control of salinity.
Water could be pumped from the sea in order to desalinate sea water or a structure could be built over the water itself.
Sewerage, polluted water or even vegetation can be used to provide a source for production.