Holding Tanks & Marine Sanitation - Hold n' Treat system by RARITAN

Tanks, Holding & Water Tanks

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Many people feel that dealing with the contents of a holding tank is one of the least appealing (or most disgusting) aspects of boat ownership. | < Hold n' Treat > treatment system by RARITAN

Holding & Water Tanks - With the advent of the Clean Water Act- With the advent of the Clean Water Act, treatment system

Protection of the Environment: Holding tanks

Unless a boat is used in a fashion that brings it back to shore every 20 or 40 minutes, it is inevitable that the skipper and passengers will be compelled to respond to the "call of nature" while aboard.

Forty years ago, the solution was as simple as Installing a marine head that was plumbed to dump human waste and toilet tissue directly into the surrounding water.

With the advent of the Clean Water Act and similar legislation in the early 1970s, It was suddenly no longer legal to dump untreated sewage into any inland waters (like Pugel Sound), or closer than three miles from the beach if offshore. Holding tanks began appearing on newly constructed boats, and were the only legal means of dealing with human waste when less than three miles offshore. Boaters tend to be a resourceful bunch, and as soon as holding tanks were required we began Making a special trip to the pumpout dock.

The reality was that the valves were normally set lor perpetual overboard discharge - to the point that the USCG began requiring that the selector handles be wired Into the holding tank position when a vessel was cruising inland waters or less than three miles from shore. Resourceful boaters (and boat builders responding to demand) refused to be deterred by the wlred-shut Y valves or similar regulations. Macerator pumps began appearing, designed to grind up and dump overboard the contents of a holding tank. Once again, the logic was that such pumps would only be used in locations where the discharge of untreated waste was entirely legal.

The reality is that for all-too-many boaters, hitting the macerator switch became the almost exclusive means of emptying a holding tank.

As a group, boaters will do almost anything to avoid making a special trip to the pumpout dock and perhaps even waiting a turn. We don't enjoy handling vacuum hoses that have been "who knows where." because we all know entirely loo well exactly where they have been. The sight, the sound, and the smell of our own waste being sucked into the municipal sewage treatment plant will never be the "Kodak moment" of most afternoon cruises.


The Code of Federal Regulations, Title 40 (Protection of the Environment) reads: "(2) In all other waters, Coast Guard-certified marine sanitation devices installed on all vessels shall be designed and operated to either retain, dispose of. or discharge sewage. If the device has a discharge, subject to paragraph of this section, the effluent shall not have a fecal coliform bacterial count of greater than 1.000 per 100 milliliters nor visible floating solids.

"Most boaters are unaware that there's an easy way to comply very concisely with all existing water pollution laws and never have to pump out again."

Waters where a Coast Guard- certified marine sanitation device permitting discharge is allowed include coastal waters and estuaries, the Great l-akes and Inter-connected waterways, fresh-water lakes and impoundments accessible through locks, and other flowing waters that are navigable interstate by vessels subject to this regulation."

Simply put, except in waters specifically designated a "no discharge zone" by a local authority it is entirely legal to discharge Created sewage in most waters frequented by recreational boaters. In fact, when a boater uses a pumpout. that waste will be treated and then discharged back Into the local bay.

In reality, shoreside treatment facilities can be overwhelmed by storm water or an internal malfunction and it is not uncommon for millions of gallons of untreated waste to flow from the municipal treatment plants back into adjoining waters.

Unless we are in a specifically designated "no discharge zone." It is entirely legal and by no means irresponsible to dump adequately treated waste back into the water.


Pouring a bottle of perfumed formaldehyde down the toilet and into the holding
tank doesn't constitute an approved treatment. Neither does pouring perfumed formaldehyde into the system and grinding up the chunks meet the USCG requirements. Something more sophisticated Is required, and something more sophisticated is commonly available.

It Is critical to bear in mind the two major premises of the USCG treatment standard: The fecal coliform count must be reduced to fewer than 1000 bacteria per 100 ml of water and no floating solids can be discharged.

New approach

Hold n' Treat system by RARITAN

Raritan, the same company that produces the LectraSan offers a Hold n' Treat system that enables boaters to comply with all "no discharge" regulations, yet potentially never bother with the mess and inconvenience of a pump out again.

Water softener salt, and is programmed to add a highly concentrated blast of saltwater to the MSD as each treatment cycle begins.

In a No Discharge Zone - a switch disables the Hold n' Treat system so that no waste can be processed or discharged Boaters entering a no discharge zone will prepare by operating the system where It Is legal to discharge properly treated waste, and if their visit to the marina, park, or other location designated "no discharge" is only a matter of a few days, nearly any holding tank of appropriate size for the vessel should be adequate to contain the waste.

The sensors, hardware, and electronic controls to adapt existing holding tanks and macerators to the Hold'n'Treat system are available for purchase, or there is a complete, fairly compact Integrated assembly that can be installed as a single unit.

The Hold n'Treat process

The process is a sophisticated yet simple approach that treats effluent to higher standards than many municipal treatment plants. (pdf)

The system uses three primary components: a holding tank, a macerator pump, and a LectraSan treatment system.

When the marine toilet is flushed, all of the waste is directed Into the vessels holding tank. When sensors detect that the holding tank has reached two-thirds capacity, the macerator pump is automatically activated.

Macerator pumps traditionally dump waste overboard, but with the Hold n' Treat system the macerator pump directs the waste to the onboard sewage treatment system, the Type I MSD.

After each "batch" of material has been transferred to the MSD. the macerator pump shuts down until the LectraSan completes the cycle. Depending on the size of the holding tank. It will take several cycles to treat and empty the contents.

As noted above, there Is an additional consideration if the marine toilet flushes with fresh water, or the boat Is being used in fresh or brackish water Additional sodium chloride must be introduced to the LectraSan for conversion to the hydrochloric acid needed to kill off the fecal coliform bacteria. In such cases, a brine tank becomes the fourth component comprising the system. The brine tank can be recharged with rock salt.

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