Eco-Machines for Water Treatment

By Jennifer Chesworth

An Eco-Machine is a water treatment system using plants and microbes, traditionally enclosed in a greenhouse or in external constructed wetlands with aquatic cells inside a greenhouse. Based on the design concepts of John Todd, eco-machines are essentially water gardens that create a controlled environment where natural processes work efficiently to purify water without the need for hazardous chemicals.

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Located in Central Pennsylvania at the Julian Woods Community, this eco-machine, completed in 1993, treats effluent from twelve households while providing greenhouse space for vegetables, herbs, and a small cut flower business.

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The effluent initially enters the system into a simulated “marsh.” It is then pumped into holding tanks.

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Four aerobic tanks, each containing a set of plant and microbial life for distinct treatment stages, perform the primary water treatment at Julian Woods.

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The water is then pumped through an ultraviolet light unit that destroys any E Coli or other bacterial life that may be present in the water. This unit is not always a part of eco-machines. It was required by the state of Pennsylvania as part of this experimental system.

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Because the system was considered experimental at the time of construction, a discharge permit was not an option for Julian Woods. Evapotranspiration was, however, already an approved method. The state required a second, full size greenhouse as part of the system at Julian Woods, to fully perform the necessary evapotranspiration and to prevent stormwater over-flow. This provides residents with the added benefit of plenty of greenhouse space for private and commercial use.

The eco-machine at Julian Woods was funded by a grant from the Pennsylvania Department of Energy.

For more information on Eco-Machines, please see www.toddecological.com