Wednesday, May 20, 2009

Micro air separation System


Overview
Advances in providing high aeration levels and intimate contact between bubbles and the dispersed phase have led to a novel separation system, the Micro Air Separation System (MASS). The MASS significantly reduces costs, provides unrivalled separation efficiencies, uses dramatically less chemicals and less space and can perform separation operations previously impossible to achieve using traditional Dissolved Air Floatation (DAF) systems.

There are a number of key functional principles DAF systems must adhere to:

High surface area micro bubbles must be formed to maximize effluent separation. The MASS bubble size and surface area can be controlled by varying the back-pressure and the airflow rate. That the micro bubbles are stable and re-active towards the dispersed phase is of key significance.
Increasing the concentration of bubbles maximizes the lift performance. The MASS unit processes all the wastewater flow and air through a pressurized cyclone. The air dissolves and all process flows are intimately mixed in the highly aerated water.
The smaller micro bubbles adhere better to the fragile flocculated particles. The MASS produces micro bubbles that form multiple contacts and because all the process flow is being aerated, superior lift is achieved leading to high sludge concentrations.
The method of pressure control throughout the circuit is paramount for quality bubble production. The MASS is novel in that the dispersion of micro bubbles in the floatation tank is vastly improved due to the method of dissolution down the cyclone chamber.
Features and Benefits
Superior separation of contaminants. Up to 95% reduction in Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS).
Air aspiration straight from the atmosphere. No air blower or compressor required.
Small footprint reduces capital costs.
Minimal maintenance.
Process efficiency improvement. Allows for the capture and reuse of more valuable resource material, while producing water that is cleaner than water generated from competitive systems.
Modular design and ease of scale-up.
Reduced chemical consumption.
More compact sludges.
How does the MASS work?
The MASS system exploits the density difference between two phases primarily by attaching air bubbles to one phase and floating it away for collection. This idea is not new, but the method by which it is achieved using the MASS is set to revolutionize how we think about DAF systems.

The MASS works by dissolving free air from the atmosphere in a cyclone within the unit, which allows up to five times more air to be dissolved than a traditional DAF system. The pressures and forces created ensure intimate mixing of the air and the fluids to be separated, which causes the air to be fully dissolved rather than entrained. The pressures generated within the MASS are up to two times that created in traditional DAF systems thereby, further increasing the amount of air available to strip out suspended solids.

The MASS unit was designed with no moving parts. The fluid spins itself through specially designed channels, and because this is achieved without moving parts, maintenance costs are reduced significantly.

To realize effective effluent separation, it is often necessary to adjust the electro-potential (pH) of the wastewater, in addition to utilizing an air floatation system. It is also possible to use chemicals such as coagulants and flocculants to help create surfaces or structures that can easily attach to the air bubbles. Coagulants are used to bind the particulate matter together and flocculants are used to change the surface tension on the liquid/solid and or liquid/gas interfaces. The combination of all three regimes will almost always bring about separation. However, using the MASS technology, it is usually sufficient to utilize one or two of these regimes and still accomplish a satisfactory result.

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