Bilgewater Treatment


Squeaky Clean

Is your bilge fouled with polluted water? Get rid of the muck with the latest oily water separator.

Many years ago, because a now-defunct marine towing outfit I was working for at the time found itself a little short of qualified personnel, I became an instant chief engineer for a few months. I say chief, by the way, because there were no other engineers onboard the M/V Texas Star, a 100-foot utility vessel with a penchant for leaking mysteriously.

Of course, pumping the bilge on a routine basis was one of my more important jobs and a decidedly quirky one at that. The Star sported nothing remotely like an Oily Water Separator (OWS) to efficiently remove oil from bilgewater before discharging it overboard. Instead, she sported a Rube Goldbergian lash-up that seems preposterous by today’s standards. Essentially, it consisted of a Y-valve spliced into the drain hose emanating from the boat’s Maytag washer! By deploying the handle, you could direct spent, sudsy wash water into the bilge, thereby (theoretically) emulsifying oil and grease in the bilgewater before sending the stuff overboard. It’s perhaps a little hard to understand now, but 40 years ago I took this dicey arrangement for the apotheosis of environmental responsibility. Go figure!

Things change, thank goodness. Today’s international maritime regulations dictate that commercial vessels process all oily bilgewater prior to overboard discharge. Yachts are regulated as well. Indeed, Trinity Yachts, a major American builder of super-size pleasurecraft, installs an OWS on every vessel it launches these days and has been doing so for several years, according to Trinity vice president Billy Smith.

But OWS technology continues to evolve. And one of the newest developments comes from Parker Hannifin, the corporation that fields Racor and Village Marine products. At last year’s International Workboat Show, Parker introduced a new OWS system that’s just a tad more sophisticated than some others. Not only is the Bilgewater Membrane Separator (BMS) compact and constructed of heavy-duty, corrosion-resistant materials, says Parker, it also outperforms current International Maritime Organization (IMO) standards, thanks to a proprietary technology that reduces free and emulsified oil in bilgewater to levels not only below the IMO standard of 15 parts per million but, in recent type-certification testing, below three parts per million.

While BMS is available in several sizes and electrical configurations, the way it functions is virtually the same throughout the range. For starters, a first-stage pump pulls oily water into a tank where oil (thanks to a lower specific gravity than water) either rises to the top for immediate discharge to a waste container or does so after coalescing on special polypropylene and polyethylene media. Next, a second-stage pump drives the remaining water through a polishing filter. Then finally—and this is the new wrinkle—a third stage brings a Village Marine Technology (VMT) reverse-osmosis membrane to bear, thereby cutting even emulsified oil to exceptionally low levels.

BMS technology works on both new builds and retrofits. The cost of the smallest version (with a 1.5 gallon per minute capacity) is $17,250, a figure that does not include installation, a waste-oil tank, hoses, and other necessary paraphernalia. Pricing for the larger units was not available at presstime.

In any case, Parker Hannifin’s Bilgewater Membrane Separator is an up-and-comer. Take it from a guy who’s way less confused about environmental matters than he used to be. The device just may constitute the apotheosis of environmental responsibility a callow youth so naively envisioned years ago. No Maytag required!

Parker Hannifin Corp.
(310) 516-9911

This article originally appeared in the April 2011 issue of Power & Motoryacht magazine.