Letter of the Day | Why are we failing to prevent effluent leaks

THE EDITOR, Madam:

I note that there have been large fish-kills in the Rio Cobre and the Kingston Harbour. The latest Rio Cobre spill appears from reports to be from a spill from an oil storage tank of some sort. The black shade as seen on TV suggests heavy fuel oil or waste motor oil. Such spills are entirely preventable through the use of containment walls or bunds (a term used in the industry for a raised area surrounding the tank).

There are a few standards which deal with this: one is from the National Fire Protection Association, which is used by the Fire Brigade; another is from the American Petroleum Institute. As engineers we use both. Generally, they state that: if there is a single tank in the enclosing bund (read sometimes wall), it must be able to hold at least 110 per cent (that is, the contents plus one-tenth of the tank’s capacity) of the contents of the contents of the tank. If there are multiple tanks in the enclosing bund, it must be designed to contain at least 110 per cent of the contents of the largest tank.

It is also wise to add another six inches to the height of the bund to account for rainfall if the contents of the tank cannot be allowed to escape in a downpour. I have designed this kind of containment before, and, if especially heavy rainfall which may exceed the design bund’s capability, then a means of letting the water out that works similar to the kitchen gravy cup that lets you pour out the gravy without the oil, can be installed.

My question is, why have the agencies responsible not strictly enforced the containment standards of oil and other noxious liquids?

With regard to the Kingston Harbour fish-kill, the cause is almost certainly is sewage from the nearby communities, which provided ‘fertilizer’ for the algae to grow explosively. The way to prevent this is to treat all sewage to the tertiary level (not only to take out the lumps, other solids, as is generally done, but also the nutrients such as nitrates, phosphates, etc.). The only other way (which I have thought of) is to use windmill-powered air pumps to aerate the water to keep the animal life alive, even as the decaying dead algae from the algal bloom uses up the oxygen in the water. This will essentially make the harbour into a sewage treatment plant.

It might not be the perfect solution, but it can prevent the continuing collapse of life in the harbour, and accelerate its recovery. Another question is, when will we wise up and stop dumping our sewage into the harbour?

HOWARD CHIN

Member, Jamaica Institution

of Engineers