Articles & Case Studies

Phenol Phew!

Posted: Thursday 29th January 2009

You know the smell – that one that goes with childhood memories of chickenpox – Calamine Lotion. This smelly pink stuff gets some of its distinctive odour from phenol. Not too bad in small doses, but when you have a site holding more than 3 million litres of dirty grey wastewater with high concentrations of phenol, it certainly becomes overpowering. Unfortunately the neighbours thought so too and something had to be done.

One suggestion was to aerate this open tank of stagnant liquid, and so Corgin were approached to specify suitable equipment. Calculations indicated that two 5.5 kW Spiral Aerators would be adequate to supply all the oxygen and mixing required for the tanks.

However, this was only part of the problem. The tank had been infrequently desludged at an average of 7-10 year intervals and by now a large volume of inactive sludge would have accumulated in the depths. What would happen when two powerful aerator/mixers began their task? A massive uncontrolled release of trapped gases? These questions were a concern to Corgin’s technical team.

It was decided to begin operation with only one aerator running under close supervision, and to monitor the results before starting the second aerator. The two aerators were duly installed one Friday morning and were soon commissioned after little more than four hours on site. One aerator was then left running, with the responsible operator under strict instructions to switch it off at the onset of any unacceptable increase in odours.

Corgin contacted the operator with bated breath as the following Monday dawned. Imagine the delight when Corgin learnt that both aerators were already in full use, odours had virtually disappeared and a definite change in

the wastewater colour had been observed. From a deep grey appearance the wastewater now showed the brown tones indicative of the beginnings of biological activity.

Needless to say, the site operator was astounded, and like Corgin, was delighted with such a satisfying result to a somewhat unusual application of the Spiral Aerator.

Spiral Aerators are available for both rental and outright purchase, for use in a wide variety of situations where a high mixing capability is required along with aeration. They are particularly efficient in treatment tanks with large surface areas relative to depth, such as oxidation ditches, lagoons, shallow tanks and balance tanks.

German-engineered Spiral Aerators are also virtually maintenance-free – they have no submerged bearings or wearing parts, only stainless steel and GRP components below water level, and the helicoid propeller is designed to prevent clogging with rags or debris.

Tel: 01785 229300

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