Arboretum Foundation receiving grant for composting toilet system

The Arboretum Foundation has received a $22,200 Neighborhood Matching Fund grant to install a composting toilet system across from the Pacific Connections Gardens.

There are currently public restrooms on the north end of the arboretum, at the Graham Visitors Center, and another at the Seattle Japanese Garden.

A new composting toilet system near Pacific Connections will be convenient for people walking or biking the Arboretum Loop Trail and improve access to facilities.

The Arboretum Foundation is still raising funds and volunteer time toward its $12,540 match with the Seattle Department of Neighborhoods.

Plans are to purchase a composting toilet system manufactured by Clivus Multrum, the same as can be found at the Picardo P-Patch in Wedgwood and Center for Urban Horticulture in Laurelhurst.

“The unit is solar powered and doesn’t require any connection to the water main, which makes it ideal for the location in the middle of the park,” according to Arboretum Foundation operations manager Whit Carter. “The plan is to place it in the area behind the decorative metal screens that are by the Pacific Connections Garden.”

Waste is deposited by gravity through the toilet into a composter area under the ground, which separates liquids and solids and neutralizes urea and ammonia through bacterial action. The liquid end-product contains nitrite and nitrate, and flows down to a separate storage area.

“The separation of urine from feces ensures that feces remain in an aerobic environment which includes bacteria, fungi, insects and compost worms,” according to Clivus Multrum. “The organisms slowly break down feces into a compost material that has chemical, biological and aesthetic characteristics similar to topsoil and reduces its volume by over 90%.”