Why can’t we all just get along ? – the role of the expert witness

Is the membrane water market becoming more litigious? There seem to be more court cases in the last few years, so this would suggest that it is. However, this trend masks another change. The first application to explode on to the scene in the early 2000’s was municipal drinking water. Designs were aggressive and membrane integrity was not as good as it is today. How did we avoid legal disputes?

The answer is that many of the plants did not have to run at anywhere near design flow, which is a typical characteristic of drinking water plants As an example, I remember that the UK’s largest plant at that time, Clay Lane north west of London, was designed at 132 lmh. Indeed, we were told by the client’s engineer that a competitor even suggested that they could achieve a 200 lmh flux. These days, I would recommend a flux of 70 to 80 lmh for the same conditions. Fortunately, the name plate capacity of 160 mld was rarely required and it often ran at about half of that flow.

The last 10 years has seen the dramatic rise of UF pre-treatment for seawater desalination, and this application has displaced drinking water as the lead application. A characteristic of most of these projects is that they require to operate at design flow. If a plant design is too aggressive, the consequences are felt straight away. The safety blanket of running far below name plate capacity therefore does not apply. Most desalination projects have used much more realistic design fluxes, but they occasionally suffer since the feed is challenging and the plant often needs to run at full capacity.

We therefore now have the flip side of the initial situation with low and realistic design fluxes, but a higher proportion of plants running at full capacity. Any slight degree of over-optimism in the design decisions will be exposed and the owner will want redress.

Naturally the first port of call in a commercial conflict will be the supplier since they have the best knowledge of what their membrane can do. However, an independent brings a broader experience to bear and is not encumbered by the project’s history or by decisions taken by commercial colleagues.

My experience in these conflicts has been fascinating. Often, cases don’t get to court, and an ‘amicable’ settlement is reached. However, sometimes too much has been invested in the dispute which makes it difficult to back down. Whereas the technical expert tends to see issues from both angles, the legal teams bring a different perspective with a clear focus on behalf of their client. Whether a particular technical expert helps their case depends on the questions he or she is asked.

I think the current wave of litigations stems from designs a few years ago which were too aggressive and/or products which were insufficiently robust. Nowadays, designs are more likely to be appropriate and products have definitely improved. However, into this mix, commercial pressures continue to increase so we are probably not out of the woods yet. Maybe it will take a revolution in technology to eliminate any potential for product failure or under-performance. Or is the problem that we consider the UF membrane process in isolation rather than the membrane process flowsheet holistically?