The
Technology
The Challenge
The efficient separation of solids from liquids remains a major challenge for plant operators in many industry sectors including chemical engineering, water and wastewater treatment, pharmaceuticals, minerals reclamation and food processing.
Conventional methods of separation include filters, thickeners and clarifiers. Alternative technologies include centrifuges, dissolved air flotation (DAF) and membranes. Disadvantages of these methods include (any of):
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High residual moisture content of the concentrate increases waste disposal costs |
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Require regular cleaning, often with difficulty and resulting on long outages |
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Slow, no on-line control of the process and highly sensitive to variations in the consistency of the medium being treated |
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Large plant footprint – difficult to bypass when problems occur and, if only one unit affordable, critical to plant operation |
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Use of aggressive chemicals such as peroxides |
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Substantial capital and running costs (eg power consumption) |
Ultimately, many of these methods are so inefficient that they simply pass the separation problem to the next phase of the process.
The Solution
FILTRA has developed a novel, efficient, low cost liquid/solid separation system. It requires no chemicals (though can be used with a coagulant in specific applications); has a relatively high separation speed but achieves this in a compact, energy efficient unit that can increase the efficiency of existing separation technologies or even, in some cases, replace them. The design is fully transportable and may be integrated into existing infrastructure or, in future, form the basis of new plant designs.
The new technology uses centripetal forces to achieve separation. It operates at low rotational speeds (typically around 300-450rpm) to provide a clear filtrate and a concentrate stream of thickened solids.
The Outcomes and Applications
FILTRA’s technology has been tested with biosolids, chemical sludges, untreated waters and wastewaters. Residence time in the separator can be as low as a few seconds (over 100 times faster than thickeners and clarifiers) and the separation is continuous. Inlet stream volumes are typically 50-100 litres/minute which, although modest at face value, is actually an advantage since a number of FILTRA units can be used in parallel, thereby avoiding the bottleneck issues associated with many large scale – and high cost - plant processes.
Costing a fraction of a conventional clarifier and using about 1/50 of the area equivalent, this is a real breakthrough in separation efficiency. |
