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Un projet pilote d'un édifice vert dans les Maritimes : Centre nature de Cap Jourimain

Il y a dix ans, plusieurs de ceux qui étaient impliqués dans le développement du Centre nature de Cap Jourimain étaient déterminés que les installations deviendraient une vitrine pour les " technologies vertes. " Ces technologies, explique l'auteur Ramsey Hart, devaient minimiser les effets environnementaux des installations tout en servant de modèle de pratiques de construction écologiquement acceptables.

Ce Centre nature, situé à Bayfield au N.-B. a été parachevé en 2000. De toutes les diverses technologies vertes utilisées au Centre, peut-être la plus radicale, la plus efficace et celle qui est la plus notable, ce sont les toilettes à compost. Parce que ces toilettes n'utilisent presque pas d'eau, elles empêchent d'utiliser environ 1,5 million de litres d'eau par année et elles évitent la nécessité de traiter un montant équivalent d'eaux d'égout! D'autres technologies vertes sont aussi utilisées au centre comme un système de traitement des eaux grises, le chauffage et la climatisation géothermique et le chauffage solaire de l'eau.

Peut-être pas un modèle parfait d'édifice vert, le Centre nature de Cap Jourimain constitue une réalisation significative d'incorporation de technologies vertes dans un édifice public régulièrement fréquenté.

A Pioneer Green Building Project in the Maritimes: Cape Jourimain Nature Centre

Ramsey Hart
Cape Jourimain Nature Centre
December 2007

en years ago, when a group of local citizens and representatives of various federal and provincial departments conceived of the idea of Cape Jourimain Nature Centre, environmental issues such as climate change were not at the fore of public consciousness as they are today. Nevertheless, from the very beginning of the ambitious project, many of those involved were determined that the facility would showcase seldom seen "green technologies." These technologies, it was hoped, would minimise the environmental impacts of the facility while serving as a model of environmentally responsible building practices.

The Nature Centre, located in Bayfield NB, was completed in 2000 and was built to serve a variety of purposes, including a provincial welcome centre for people arriving to NB via the Confederation Bridge from PEI, providing environmental educational opportunities for tourists and residents, and generating tourism revenue and job opportunities to help offset the impacts of the closing of the PEI - NB ferry service. One of the main reasons for the environmental agenda behind the project was the fact that the nature centre was built within the boundaries of a National Wildlife Area. The project also faced serious limitations in the supply of freshwater at the site, a reality that helped push the green building agenda forward.


Composting toilet at Cape Jourimain Nature Centre
(Photo: Ramsey Hart)

Of the various green technologies at the Centre, perhaps the most radical, effective, and highest profile is the composting toilets. Just about everyone who visits the centre makes use of these water-saving wonders made by Clivus Multrum. Because the toilets use almost no water, they prevent the use of approximately 1.5 million litres of water a year, and the need to treat an equivalent amount of sewage! Rather than flushing waste away with good clean water, wastes fall into a composting chamber and are naturally broken down into pathogen-free organic matter and liquid "compost tea."

Crucial to the design of the toilets is the sloped chamber (which is also the translation of Clivus Multurm from Swedish) that allows liquid to drain away from the compost pile and allows the solid waste to slowly slip down the slope as it decomposes. The composting process reduces the volume of waste by roughly 90%. The reduction in volume is so great that, to date, no solids have been removed from the composters, despite being in service for seven years and used by hundreds of thousands of visitors.


Sloped chamber that allows liquid to drain away from the compost pile and allows the solid waste to slowly slip down the slope as it decomposes.
(Photo: Ramsey Hart)

Though the composting toilets deal with the most problematic of the wastes created at the centre, grey water (waste water that does not contain sewage) is still created in the washrooms from hand washing, and from the Centre's kitchens. These wastes are sent to concrete septic tanks and then to a treatment system designed and built by Waterloo Biofilter. This system is made up of four large tanks full of sponges. The grey water is sprayed over the sponges and a host of bacteria colonize the sponges providing biological treatment of the wastewater. The final step in the grey water treatment process is an infiltration bed where the water is pumped to an irrigation system laid out on the ground in the woods surrounding the centre. The physical characteristics of the soil and the soil organisms provide a final treatment as the water moves down through the soil to help recharge the groundwater table. Water testing of the greywater system has consistently shown excellent performance. The only difficulty has been with the maintenance of the many pumps, sprayers, etc., that are required to move the water through the system. Groundwater is further conserved by the collection of rainwater in a massive 2000-gallon cistern. In all but the driest of years this provides adequate water for hand-washing, cleaning, and other non-potable uses, saving the precious groundwater for drinking and food preparation

Though not as apparent to most visitors as the composting toilets, the Centre's geothermal heating and cooling system goes a long way to further reducing its ecological footprint. Geothermal heating is one of the most efficient ways of heating or cooling our indoor environments. It makes use of the fact that below the surface, the earth is at a relatively constant temperature of 8 ºC. This heat can be used in combination with a heat pump to warm buildings in winter. Conversely, the earth can be used as a heat sink, to absorb heat taken out of the buildings in the summer. It has taken the Centre's staff some time to get the hang of running the advanced computer system used to manage the geothermal system but now that they have figured it out, it is operating efficiently in both winter and summer.

The geothermal system, though efficient, does require electricity and with the physical size of the centre, it's vaulted ceilings, and massive windows, it still takes a substantial amount of energy to heat and cool. Though some interest was expressed in the early design phase, no use of passive solar technologies were included in the final design. Fortunately, the final design did include many windows, which can be opened to help cool the buildings as there is just about always a breeze along the coast. This is truly a green a cooling system that doesn't need computers to control it!

In 2006, the Centre installed a thermal solar water heater to pre-heat water used in the restaurant kitchen. With water heating being one of the most significant uses of electricity in many homes and businesses, and the relative ease of retro-fitting panels into existing structures, thermal water heating is a great way to use clean, renewable solar power.


Thermal solar water heater used to pre-heat water used in Cape Jourimain's kitchen. 
(Photo: Ramsey Hart)

With compact fluorescent light bulbs being all the rage today, one of the more glaring oversights in the construction of the Centre was the use of very inefficient lighting in much of the facility. While options may have been limited at the time of construction, the use of very specialized fixtures with hard to find, expensive, and energy-sucking bulbs was certainly an oversight. Where possible, more efficient bulbs are now being used, and as much as possible the abundant natural light from the many windows is relied upon with some lights only being used on very cloudy days or in the early morning and evening. Though these kinds of behavioural changes may seem like tinkering around the edges, better management of the complete energy system at the Centre has resulted in substantial savings, well above and beyond those predicted by a more conventional engineering approach to energy efficiency.

Though certainly not a perfect model of green building, Cape Jourimain Nature Centre does represent a significant achievement for incorporating green technologies into a highly used public building. Of course we can learn just as well from what worked, as what was overlooked or hasn't worked so well. A few overall lessons might be: don't be afraid to do what hasn't been done, as much as possible keep systems simple and consider the long-term maintenance and operating costs of every system, and, for a truly green building, the ethic of efficiency and reducing ecological footprints should extend to every aspect of the project, from waste handling to lighting selection. If you are interested in seeing the centre, the staff members are always thrilled to show off its green technologies. The centre is open from May to October. More information can also be found online at www.capejourimain.ca.