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Re: GBlist: Living Machines



We are designing an environmental education center for the U.S. Fish &
Wildlife Service at a wetlands refuge in Philadelphia.  We have proposed a
"solar aquatics" system to treat the waste water and recycle it for toilet
flushing. Solar Aquatics is a similar, but competing, system to the Living
Machines. (see the article in EBN for a discussion of both types).

Our rationale for the system in this facility, which is quite close to a
public sewer line, is two fold:

1)  The system will make the point that we should take responsibility for
our water resources, including waste water, and if possible, reuse it on
site.  We will discharge any extra effluent from the system onto the land,
as irrigation for native plants around the building.

2)  At this wetlands wildlife refuge, it is even more important to
emphasize the importance of water and the cleansing & filtering power of
wetlands and marshes.  Parts of he Solar Aquatics and Living Machine
systems are called "artificial marshes."  We intend to make this water
treatment system an integral part of the environmental education exhibits
by using the manmade marsh to demonstrate the functioning of the natural
marsh.  We are most excited about the possibility of this system to both
function and act as a powerful teaching tool.

Our system will be housed in a greenhouse structure attached to a part of
the building containing classrooms.  We will be bringing the public into
the greenhouse but restricting their access to the actual working
components.  They will be able to see the tanks and marshes and the
explosion of greenery which the fertile conditions ignite.  We will need
some auxiliary heating for the coldest  nights of the winter to keep the
air temperature above 45 deg. (F), however, we will be able to use some of
the excess heat from the greenhouse on sunny winter days for the
classrooms.  We intend to include a small photovoltaic array to provide
power for the small pumps and fans required by the system.

We visited three existing systems,  two in Toronto (The Body Shop's HQ and
a demonstration system at the Ontario Science Center) and one in central
Pennsylvania, serving a small community of a dozen homes.  This last was
designed by our consultant, Mike Zavoda, and was largely built by the
residents.  It's been operating for 4 years with no problems and little
maintenance.  The treated effluent is recycled to the houses for toilet
flushing.  In addition, using an evapo-transpiration system which sprays
some of the treated water into two adjoining greenhouses, one of the
residents grows and sells cut flowers at a local farmers' market.  They
also grow food for themselves in these greenhouses.

Maintenance needs mainly involve monitoring the working parts (pumps,
valves, etc.) and standard gardening chores (removing dead foliage, cutting
back agressive plants, weeding, etc.).  

 We also explored the alternative of composting toilets.  These seemed less
appropriate for our use - we will need over 20 toilets due to the size,
layout and funtions of the building.  The folks at Clivus Multrum described
their products as being about returning the solid waste to the soil and
closing that loop.  The liquid waste was somewhat of a problem for the
quantity of fixtures we have, and would have to be collected in a tank and
periodically pumped out.  

One troubling aspect of the living machines is that a septic tank is still
required to handle the solid waste.  It will have to be pumped out
periodically, less often than a standard septic system, but still not a
totally closed loop.  

For our project, which is so close to the municipal sewer, there is not an
economic reason to install the system. In the system in central
Pennsylvania, however, the cost of the solar aquatics system was less than
the cost of hooking all the houses up to the municipal sewer, due to the
distance from the closest main.  

People should also be aware of a recent EPA report which is somewhat
critical of this technology.  I have not seen a copy yet and don't have the
citation, but I understand that it looks as several municipal scale
installations in the east and reviewed their performance using traditional
waste treatment criteria.  When I get a copy, I will post the citation.

Muscoe Martin, AIA
Susan Maxman Architects
123 S. 22nd Street
Philadelphia, PA 19103 USA
smarch@compuserve.com
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