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ECUBE™ Brine Evaporation Accelerator Saves Money
A patent is pending for an Australian device, designed to minimise problems associated with the disposal of highly saline water, generated by reverse osmosis machines producing potable water from brackish or saline sources.
A solar and wind powered brine evaporation accelerator called ECUBE™, it comes usually as a 3m by 3m by 3m module. Suspended and held within a frame made of 304 grade stainless steel, are porous evaporator panels, onto which the RO plant pumps its waste brine.
Before reaching the panels the brine is heated by a solar powered water heater. Wind passing through the porous evaporator, then evaporates the water at 10 times the rate normally achievable in evaporation ponds.
ECUBE™ is ideally suited for areas that are not sewered and even areas which are, but where a RO plant is discharging more than the amount of salt to the sewer that the local authority allows.
The brine evaporation cubes cost between one third and one half of the investment needed for evaporation ponds, the only practical way until now of disposing of large quantities of brine, says its inventor and joint principal of AVIVAPURE™ Pty Ltd, Frank Palmer. AVIVAPURE™ makes reverse osmosis plants inMelbourneand markets them aroundAustralia.
Palmer said, "In order to dispose of that brine in the past, Reverse Osmosis plant operators have had to build large evaporation ponds. So by producing say 600,000L of pure water a day, a reverse osmosis plant operator, would have anywhere from 200,000 to 500,000L a day of waste brine to dispose of, containing between 30,000 and 60,000 ppm of dissolved solids.
"And the operator may have had to spend $400,000 to $800,000, for two polyethylene lined evaporation ponds, each about 140m square by one metre deep, to evaporate that volume of brine effectively," he said.
Palmer said the disadvantage, apart from the expense, is that evaporation ponds take up considerable space and otherwise valuable level ground. "In the case of mine sites, soil can be gravelly. So the formed pond needs to be lined with compacted finer material which will not puncture the liner, and that can be expensive."
When brine from the ECUBE™ reaches a concentration of about 226,000ppm, most of the salts will crystallise and can be removed, and the remaining liquid known as bittern, can be drained. The bittern can be reprocessed, sold or discharged into a sewer under a trade waste agreement. The crystalline salt can be dried and sold for between $80 and $100 a tonne, Palmer said.
He said the whole ECUBE™ evaporation acceleration process is environmentally friendly because it uses solar and wind energy to increase the evaporation rate. When evaporation is high in summer, a small pump with an electric motor consuming about 1kW, can be used to maximise evaporation by placing more brine on the panels, he said.
In places where wind is limited a fan can be mounted onto the ECUBE™. But it would require about 3kW of electric power to achieve the desired airflow, Palmer said.
Already a mining company, a regional water authority and a golf club have expressed serious interest in the ECUBE™ and an engineering firm in Perth has expressed interest in making them.
Other water users like winegrowers, horticulturalists, government authorities, farmers, secondary industry, breweries and sports clubs, would find the ECUBE™ a viable alternative to their existing disposal methods. "Also, ECUBE™ will for some, make reverse osmosis their only viable possibility of obtaining adequate potable water supplies," Palmer said.
More information: Frank Palmer, AVIVAPURE Pty Ltd, 03 9822 1011, frank@avivapure.com.au , www.avivapure.com.au
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Fish farm relies on desalinated bore water for its viability
For Richard Fassalter, water quality is absolutely vital to the success of his fish farming venture.
He has about 1000 Murraycod, yellow belly and silver perch in shedded tanks on his farm near Broadford, about 80km north of Melbourne. About 700 weigh in the region of 500g each while the balance are fingerlings he is growing out.
Most of his water comes from a bore. There is plenty of underground water but it is highly mineralised, Richard says. So he pumps it firstly through an AVIVAPURE reverse osmosis unit he bought for the purpose. That gives him absolutely pure water which he can then manipulate to exactly suit the needs of his fish.
To that he normally adds about 5% of the original fairly hard, untreated bore water, as well as salt and minerals, to make it most amenable for his fish.
Then Richard uses mechanical and biological filters to keep bacteria in the water in check. Nevertheless he needs about 3000L of pure water a day from his reverse osmosis unit, to keep the acidity (pH) and mineral balance right. Periodically he has the water tested by a lab to ensure he has the formula right.
Come mid spring, Richard will inject his fish with fertility drugs, to encourage them to spawn, towards the end of October. Then he will transfer the spawn to other tanks. This will take his desalinated water demand up to about 10,000L a day as he grows the fish out. "Growing out needs much more water," he said.
Richard says his AVIVAPURE reverse osmosis unit has worked perfectly. "I just don't have to worry about it," he said.
He looked at other reverse osmosis units available in Australia and closely considered another brand available from Queensland. "But when I saw the price of the AVIVAPURE unit, and the fact it was made in Victoria, I opted for it," he said.
Currently Murray Cod are the easiest to grow out and provide the best dollar return. Yellow belly are more difficult to grow, as only about half will eat pellets, which Richard relies on as feed for them. Those who won't take pellets will likely go to farmers who wish to stock their dams with fish but who are not necessarily interested in making money out of that sort of venture.
Richard says people interested in building even the most basic fish farm, would need to spend at least $250,000 to achieve something that was at least adequate. "But to really get ahead, you need to spend in the region of $500,000," he said.
However he says the aquaculture industry is growing substantially, as natural fisheries prove unsustainable, because they are being subjected to much greater fishing pressures.
Reverse osmosis plant pays for itself in slashed fungicide applications
A bore-fed reverse osmosis plant, Victorian horticulturalist Zbigniew Skrodzki installed in mid November 2007, paid for itself after less than a year in operation.
It has done that because the pristine water it provides is clean and disease free. So Ziggy was able to cut normal Ridomil fungicide applications by more than half, saving about $5000 for fungicide alone plus application costs. When using organic matter-rich dam water - the catchment covers a long stretch of wide roadway uphill from Ziggy's block - blocked sprinklers are a constant and frustrating problem, which it is difficult to put a cost on.
When on dam water - it only holds about 2ML - he has to apply the fungicide as often as twice a week to keep botrytis under control. But when he is using the water from the RO unit, he cuts back from twice weekly to weekly and sometimes to fortnightly fungicide applications.
Another expense involved with using dam water is calcium chloride filters to strip most diseases from the water. But they do not work as well as the reverse osmosis plant because the water from that is absolutely pure.
His Hortwide nursery in Wandong, 45km north ofMelbourne, has been subject to stage 4 water restrictions for about five years. So while he has always had the dam to keep mostly flowers - about 50 varieties including potted colours like petunias, impatiens and marigolds at this time of year and pansies, violets and primulas in winter - growing under plastic, it was not enough considering the prolonged drought.
Because of reduced water demand in winter, Ziggy is able to hand water his plants to match their reduced and varied moisture needs. That means the 10,000 litres a day of pure water available from the reverse osmosis plant, is more than enough to keep his hundreds of thousands of plants going through the cooler months, on about 10mm a week.
In summer when the temperature is in the high 30s and there is a hot north wind, the plants might need as much as 10mm a day and the sprinklers have to be turned on. All up they need about 2000mm a year to keep growing properly.
Ziggy had a 60m bore drilled to boost his supply about three years ago. It is at least 120m from the ominously-named Dry Creek on his boundary, so does not draw on what little creek water there is. But like most bores now, the water was too salty at about 7800EC, to use directly on sensitive little flowers.
Ziggy sells nearly 1,000,000 plants a year or about 20,000 plants a week, largely using two Iveco vans each carrying about 3000 plants each. The day before this writer's visit, one had been to Echuca via a long sweep to the west and another had been as far as Wodonga, again covering a lot of territory in between. Altogether they service about 100 nurseries a week, selling on spec when they get there, what the nurseries want.
Big retailers like K Mart are significant customers too. So if you're browsing one of its nurseries in Victoria, chances are Ziggy's plants will be showing what a predicatable water supply can produce.
While the town water supply has diminished because of the drought, Zbigniew has steadily produced more plants, and over five years has achieved a bigger market share to handle that volume. But competition is tough and he has had to reduce his prices by about 5% for each of the last two years. The fuel bill too doubled for a while last year with oil price increases, from $2000 to $4000 a month.
Ziggy, 21 years in Australia in September 2009, earned a degree in horticulture in Poland. He worked first of all for the Melbourne City Council Parks and Gardens section when he arrived in 1988, before working in other horticultural pursuits. Gradually he worked part time to develop a back yard poly house plant business which evolved into the Wandong business he runs today.
The nuts and bolts of reverse osmosis
At Wandong, a Melbourne-based company AVIVAPURE Pty Ltd, installed a Grundfos bore pump in Ziggy Skrodski's 60-m deep bore, which pumps the salty water directly to reverse osmosis membranes in a locally made plant.
For $4.50 a day, plus the cost of running the bore pump, it produces about 10,000 litres of practically pure water. That is water from which 99% of solutes and contaminants have been removed, which Ziggy pumps directly into his irrigation supply tank.
AVIVAPURE reverse osmosis plants continue to evolve and are significantly quieter and more reliable than even a couple of years ago. Also, with new technology, water high in iron or silica can now be pre-treated, so the RO plant can handle it. Until recently this water could not be purified through a RO plant.
Fully installed units similar to one Ziggy has, cost about $25,000 plus GST.
Based on water tests, the plants are customised to process water as salty as 7800EC (5000ppmTDS) down to 31EC (20ppmTDS) or one third the salinity of rain.
Maintenance requirements for a RO plant are minimal. It is advisable to check daily the level of antiscalant a plant needs to automatically keep the membranes clean. Depending on the water chemistry, membranes will need to be chemically cleaned for a couple of hours every six weeks to six months. In Zbigniew's case, he has had to clean the membranes, with food grade citric acid and other harmless chemicals, only twice in the last year.
Disposal of waste water - it may be as little as 10% of the total - is not usually a problem. MostMelbournewater authorities allow owners of private homes to discharge up to 200kg a day of sodium chloride to sewer systems. Commercial premises need to obtain trade waste agreements however.