Monthly Archives: May 2009

Use Your Holding Tank

Number one on every boater’s “green list” should be the proper disposal of human sewage. This single measure can make a noticeable difference in the coastal environment because untreated waste can have a three-fold impact: it can be visually distasteful, it presents a health hazard, and it creates nitrogen pollution which lowers oxygen levels necessary for aquatic life (eutrophication) and causes algal blooms.

Pumping untreated “black water” overboard is also illegal. The Federal Clean Vessel Act Grant Program prohibits boaters from discharging raw, untreated sewage – which is what spews out of most sailboat holding tanks — within all navigable US waters. That means anywhere within three miles of either US ocean. In very fragile and sensitive regions, specific “No Discharge Zones” have been designated where it is now illegal to dump even treated sewage (see discussion of NDZs).

Just the concept of a holding tank is unpleasant – there‘s no way around it. So keeping the tanks clean and working right is a priority because, as many of us have discovered, no one wants the job of fixing them – for any amount of money! At every pump-out, purge the tank by pumping the head handle(s) about 50-60 times each sending many more gallons of fresh sea water into the tank. And then pump out again – until the outflow is absolutely clear.

An additional step, cribbed from R-V users, suggests mixing water softener and a non-toxic biodegradable detergent into a jug of water, then pumping it into the cleaned out tank. The motion of the boat will slosh this mixture throughout the tank keeping the interior slick so the gunk won’t stick- and it will continue to act on the new black water until the next pump-out. (Note: Don’t combine this recipe with one of the tank treatments described below unless you understand the chemistry of each.) Also, consider a tank monitor – to prevent overfilling.

It’s All About the Head

For many women, boating is all about the head – and odors of any kind are simply not acceptable. And, it is not just sewage that causes odor; it’s also all those microorganisms that are arriving with the seawater and dying and decaying. To keep the tank and hoses disinfected and smelling fresh, consider multiple approaches.

1. Choose either a bio-active (i.e.K.O. Kills), nitrate (Nitrator) or enzyme (Headzyme) treatment – each has its pros and cons, but they all break down waste (those odor-producing anaerobic bacteria) with environmentally friendly processes. Chemical treatments, on the other hand, kill bacteria but don’t destroy odors – they just mask them with deodorants – and they aren’t particularly environmentally friendly.

2. Check the connections and the hoses periodically – they wear out, get porous and then leak. When it’s replacement time, look for smooth-walled, heavy-duty, odor-free hoses.

3. Consider adding an air-injection system, which helps the waste-consuming (aerobic) bacteria thrive – like Graco’s “Sweettank.”

4. Use “good ole” Stick-Ups in the head and near the “Y” valve. Lemon smells the freshest and balances any lingering odors. Or better, a couple drops of an antiseptic essential oil.

Educating your crew and guests about good head practices will also stave off embarrassingly unpleasant situations. After you’ve given a newbie guest the regular head tour, point to the little sign that you’ve posted. It clearly reminds them how the head works and explains exactly what goes in it and what doesn’t – and notes the location of discrete disposal bags for everything that doesn’t. What goes in should be limited to human waste and reasonably small amounts of biodegradable toilet paper.