Electro-osmotic Technology

Groundwater intrusion through a building’s foundation can cause serious damage. In addition to increased concrete deterioration and accelerated rebar corrosion, basement dampness can ruin expensive electrical and mechanical equipment, which is often located in basement areas; can increase maintenance requirements through frequent repainting or cleaning to combat mould growth, and can make affected areas uninhabitable or even unusable due to poor air quality.

In selective problem areas, the usual approach to the treatment of water intrusion problems is to ‘trench and drain’, in other words, to excavate and expose the wall area and the base of the foundation, to replace waterproofing on the wall surface, and to install a drain tile system around the building or affected area. Other areas, such as floors, are untreatable using conventional methods.

MPS offers an alternative that can mitigate some water-related problems from the interior of affected areas without the cost of excavation. Further, by lessening water seepage through concrete walls and floors, indoor humidity is reduced, thereby alleviating corrosion damage to mechanical equipment, lessening mould problems and enhancing indoor air quality.

In 1809, F.F. Reuss originally described electro-osmosis in an experiment that showed that water could be forced to flow through a clay-water system when an external electric field was applied to the soil. Research since then has shown that flow is initiated by the movement of cations (positively charged ions) present in the pore fluid of clay, or similar porous medium such as concrete, and the water surrounding the cations moves with them. The basic physics and chemistry of electro-osmosis can be found in several textbooks and treatises (e.g. Glasstone, 1946 and Tikhomolova, 1993).

MPS functions by means of a pulse sequence which results in the pore fluid moving generally in one direction. The amplitude of the signal is typically between 20 and 40 Volts DC (VDC). The positive electrical pulse causes cations (e.g., Ca++) and associated water molecules to move from the dry side towards the wet side, against the direction of flow induced by the hydraulic gradient, thus preventing water penetration through the below-grade concrete structure. The amount of moisture within the concrete can be controlled in order to prevent over-drying of the concrete matrix and subsequent degradation.

An MPS installation involves inserting anodes (positive electrodes) into the concrete wall or floor on the inside of the structure and by placing cathodes (negative electrodes) in the soil directly outside the structure. The density of the anode and cathode placement is determined from initial resistivity tests of the masonry structure and the soil. The objective is to achieve a certain current density and thus create an electrical field strength in the masonry structure sufficient to overcome the force exerted on the water molecules by the hydraulic gradient.

The focus of research and development for the MPS system over the past 10 years has been to gain a full understanding of the physics of reverse osmotic technology and to apply that knowledge to the development of a commercially viable system which would perform to specified criteria in many and varied practical applications. The key to the MPS system’s proven capability is the application of this advanced proprietary technology for the control of the electro-osmotic multi pulse sequencing and amplitude through sophisticated control and regulatory mechanisms.

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