Potty talk: Wastewater treatment techniques promise win-win

Composting toilets do not look much different than traditional toilets but the environmental impact is much less. — Photo courtesy of Clivus New England

Advances in wastewater treatment technology provide home, municipal, and commercial property owners with low-tech ways to treat their own dirty water on-site and to use the clean, recycled product to provide subsurface irrigation and to beautify property.

The newest offerings provide compact, low-tech, nitrogen-removing, and odorless systems for handling “blackwater” wastes from toilets and urinals and “greywater” waste from showers, sinks, and dishwashers, etc.

Earlier in the month, Joe Ducharme, general manager of Clivus New England in North Andover, explained how his systems work to a rapt early morning crowd of 30 at the West Tisbury Library. The Times tagged along to get information on wastewater systems for Island property owners.

Essentially, blackwater waste is gathered in a basement area composting container, to which wood chips are systemically added, a process that yields garden-variety humus, which can be used as an aesthetically pleasing and enriching soil nutrient. The blackwater process uses an ultra-high efficiency toilet that releases anti-bacterial and cleansing enzymes during the otherwise conventional flushing process. The Clivus toilet disposes waste via a gravity-flow system, typically combined with a foam agent and three ounces of water, compared with 1.6 gallons used by conventional flush systems.

A trapless toilet must be used with a composting system so that gasses and odors are carried away to the composting area. Traditional toilets use flushing water to provide a barrier against odors and gasses entering the user’s environment.

Greywater treatment is an even simpler process, as Mr. Ducharme explained it. The greywater is essentially strained and filtered to pick up particulate matter from the shower or the washing machine. The freshened water can then be released into a soil absorption system below the ground on the property. The filters are periodically removed, cleaned, and returned to their places above a filtering tank for the cleaned up water.

Discussions of toilets and dirty water can elicit the “Ewww!” response or may stimulate our adolescent bathroom humor side. Mr. Ducharme’s audience exhibited a bare minimum of either.

In fact, most of the folks crowded into the rear main reading room were members of the library building committee or town officials, selectmen, and building inspector Ernie Mendenhall, charged with overseeing the $6 million library expansion.

The audience was all about the money and the environment. They wanted to know whether on-site treatment systems work, whether they are cost-efficient and environmentally friendly.

Mr. Ducharme’s presentation was part of his company’s bid to provide the plumbing-based service to the new library. Building committee chairman Leah Smith said the library must be prepared to handle up to 2,000 visitors per day. Mr. Ducharme and others estimated that half the visitors would use bathrooms requiring blackwater or greywater treatment.

On-site treatment systems have been in place in the Northeast for at least 30 years. Audience member Richard Knabel, a West Tisbury selectman, noted a facility with which he was associated in the late 1970s had an early version on-site treatment that he said produced mixed results.

However, interest in on-site treatment processes began to spike six years ago when Massachusetts, concerned about the increased levels of nitrogen load in community watersheds, tightened its wastewater regulations using conventional systems and also amended its Title V regulations to allow on-site treatment systems to be used.

Nitrogen loading is a bad term on the Island these days. Nitrogen, a common element in household water use and in lawn and garden chemicals, is toxic to ecological balance in ponds, lakes and streams. Sengekontacket Pond in Oak Bluffs undergoes regulatory angst annually around use of the pond due to over-limit bacteria and nitrogen levels.

West Tisbury’s Great Pond does not suffer at the level of Sengekontacket. However “the last water-quality tests showed nitrogen levels approaching minimum danger levels in Great Pond,” town conservation committee member Prudy Burt said.

Following the meeting, Ms. Burt said she supported an on-site wastewater treatment system for the expanded library rather than the traditional discharging method using leaching fields and septic tanks with solid waste hauled away.

Composting/greywater systems cannot be integrated with a traditional system, according to Mr. Ducharme, whose company services some 30 systems on Island, some in place since the mid-1970s, he said in an interview following the meeting. He said Island users range to the Wampanoag Tribe of Gay Head’s (Aquinnah) administration building, The Nature Conservancy, Chilmark General Store, and in recent Westminster affordable housing construction.

Installation costs begin around $12,000 for either new construction or retrofits. Several Island sources put the cost of installing a traditional leaching field/septic system at about the same level. Homeowners should also calibrate the cost of servicing both systems over time, sources suggested. Installation costs aside, the composting system may be a good option for small lot owners in light of tougher state regulations regarding nitrogen and bacteria seepage into groundwater.

Mr. Ducharme said he is unaware of grants or economic stimulus packages available for private composting/greywater systems as there have been for heating/cooling energy use system. He said some funds are available for use on public properties, such as barrier beaches.

“The key benefits include elimination of traditional sewage systems altogether, a drastic reduction in water use and in wastewater flow as a result of separating the flow between grey and black wastewater sources,” he said.

“A barrier beach project saved a million gallons of water a year and a Nantucket homeowner reduced pump-outs of greywater from weekly to an annual basis,” he said, noting that haulage may be used for treated compost liquid to eliminate 100 percent of nitrogen on the site.

For more information about composting toilets, visit clivusne.com.

Jack Shea of Vineyard Haven is a regular contributor to The Times.