Soft starters cut downtime at treatment plant

Edited by the Engineeringtalk editorial team Jul 27, 2005

Fairford Electronics has worked with long-standing partner Jayshree Electron to provide soft starting and soft stopping control on aerator motors at the MMC water treatment plant that serves Bombay.

Fairford Electronics has expanded its business on the Indian subcontinent, working with its long-standing partner Jayshree Electron to provide soft starting and soft stopping control on aerator motors at the MMC water treatment plant that serves Bombay, the most populous city in India, with over 18 million inhabitants.

In co-operation with Jayshree Electron, Fairford has supplied control boards from its QFE series soft starter, and software, to overcome a stopping problem on floating aerators at the MMC treatment plant.

Aeration is a secondary treatment process, where wastewater is mixed with a culture of micro-organisms in an aeration tank.

In order to sustain the biological activity in the aeration tank, surface aerators are employed.

These stir-up the surface of the water, helping oxygen to dissolve.

The aerator mechanism, essentially a paddle with a drive motor, is usually vertically mounted on a solid platform.

However, the aerator units at the MMC treatment works are floating units that are held in place by retaining ropes.

This would not normally be a problem, but for the fact that the motors driving the aerators are slightly undersized, a feature which causes them to snatch under stopping.

The result of this has been a succession of snapped ropes, and lost treatment time at the MMC plant.

The problem was not easy to solve, and required special software in combination with Fairford's QFE control board to overcome it.

This combination was put to the test over 2-days at the MMC Treatment works; a representative from Fairford UK being on-hand to supervise the trial and provide the software expertise to optimise the soft stopping process across a number of different aerators.

The trial was completely successful and subsequent operation of the floating aerators has been trouble-free.

"What this application demonstrates is our commitment to global support of our products, wherever they are used", commented Fairford's Technical Sales Manager David Taper.

"With increasing product from the UK supplied overseas, we have the experience and resources essential for our customers to compete effectively in worldwide markets".

Fairford is very strong in the worldwide water treatment industry: the latest application in India following an equally successful project undertaken in California.

In this project, 16 Fairford QFE soft starters were installed on the drive mechanisms of aeration paddles, as part of a $4.7 million solar power initiative to reduce escalating energy costs at a wastewater treatment plant operated by SC-OR (Sewerage Commission Oroville Region) in Oroville, California.

The Fairford soft starters are part of the demand side management system at the plant, aimed at reducing total plant load and increasing the overall efficiency of the photovoltaic solar system.