When comparing different units, can we use the capital cost per cubic metre of pollutants captured as a guide?
No. This is a mistake many clients and consulting engineers make when trying to compare the performance and cost-effectiveness of different proprietary products. There are several flaws with this approach. Whilst the capital cost can be readily found the ongoing cleaning and maintenance costs are often not added to determine a more accurate whole of life cost. Also, the effectiveness of the cleaning regime is a critical factor in the equation. If a unit is cleaned only once in the year, when in fact it requires cleaning say three times, it will obviously have been in by-pass for much of the year and so the amount of pollution collected will be less than if it had been more regularly cleaned. This would make a nonsense of any attempt to compare different units using the level of captured pollutants as a key factor. Other factors such as differences in catchment characteristics, hydrological conditions, and different methods of cleaning will also affect any comparisons.
