Water
Treatment & The Eco Restorer
 Biological waste water treatment
In this Living Machine system, anaerobically treated sewage flows into a greenhouse containing a
series of tanks. These contain species which breakdown the sewage naturally
as it moves through the tanks. In many systems there are by-products of fish
and plants being produced that can then be sold. Living Machines mirror
processes that occur in the natural world, but more intensively.
At the end of the series of tanks, the resulting water is pure enough
to be recycled. The technology is not only capable of meeting tough new
sewage outflow standards, but uses no chemicals, and has a relatively
inexpensive capital cost attached.
 Living
Technologies
Design
Using the Findhorn example, the system is housed in a single-span
greenhouse, approximately 10 Metres (M) wide by 30 M long. The flow from the
Park at Findhorn has a loading of approximately 300 people equivalents. In
other words about 60m3 waste water per day.
Anaerobic Septic Tanks
The first component of the treatment process is 3 anaerobic
bioreactors buried outside the greenhouse. The function of this component is
to reduce significantly the organic material and inorganic solids in the
wastewater. During operation, no oxygen will be present in the wastewater,
promoting the growth of anaerobic and facultative bacterial populations.
Closed Aerobic Reactor
Effluent from the anaerobic tanks flows into a closed aerobic tank in
the greenhouse. Air is introduced through fine bubble diffusers to convert
the waste water from an anaerobic to an aerobic state. Gases from the closed
aerobic tank pass through an filter system to eliminate odours.
Open Aerobic Reactors
The four aerobic tanks have diaphragm aerators and are planted with
plant species with large root masses on floating plant racks. The BOD and TSS
is reduced at this stage and ammonia nitrified.
The primary function of the plants is to provide favourable
environments for enhanced microbial activity. Bacteria and other
micro-organisms attach themselves to the large surface area of submerged
plant roots. These attached biofilms contribute significantly to the
treatment process.
Secondary plant functions include nutrient removal, metal
sequestering, pathogen destruction and some control of gas exchanges. The
main objective is to have a healthy and diverse sequence of ecosystems
present. The wide variety of plant species filling ecological niches in the
system is a key to the robust nature of natural treatment systems. The
ecological network of species creates internal biological redundancies
compared with a purely microbial system, or a monoculture duckweed system.
This gives the potential for improved efficiency and greater resilience.
The Clarifiers
The solids kept in suspension in the aerobic tanks are removed in the
Clarifier. They settle to the cone-shaped bottom of the tank and are returned
to the anaerobic primary. In the Clarifier tanks you may see tiny water
creatures such as Cyclops living in the water. They perform an important part
in both treatment and in creating a complex food chain.
The Ecological Fluidized Beds
The three Ecological Fluidized Beds in each train are filled with
light rock media. For aerobic operation, air lift pumps raise the water from
the bottom of the fluidized bed to the surface, where the water flows down
through the bed. Recycle rates can be varied up to 100 times the flow rate
through the component.
The aerobic operation provides reductions in BOD and TSS and
nitrification. For the anaerobic operation of the fluidized beds for
denitrification, mechanical pumps circulate water up through the bed. The
fluidized beds are planted and benthic animals graze the surface.
The first fluidized bed is usually run aerobically to nitrify any remaining
ammonia in the waste stream. The second fluidized bed can be run
anaerobically to denitrify. The third and final fluidized bed is run for
final denitrification and polishing.
The underlying concept behind the design involves rapid flows of water
by recycling through the media filled zones. The key attributes of an
Ecological Fluidized Bed are:
The biology is managed as a balanced ecosystem. The levels of
dissolved oxygen, and carbon to nitrogen ratios, as well as recycle rates and
bioaugmentation, are adjusted with the overall objective of reducing levels
of BOD, ammonia, total nitrogen, faecal coliform and solids.
The Greenhouse
The greenhouse is built from a galvanised steel frame, clad in a high performance
glazing system. The walls are 10 mm polycarbonate. The roof is composed of
high light transmission panels, with good thermal efficiency normally used
for solar panels.
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'Living Machine' is a trademark of Living Machines Inc. of New
Mexico, USA
Water
©2004 St.Clair Foundation, All Rights Reserved
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