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The EGL Pressure Sewer Solution Description of the
Pressure Sewer System
EGL Pressure Sewers consist of a network
of pressure pipe, much like a water pipe network and E/One
grinder units, which
are installed serving all the properties throughout the collection
system. Depending on local factors each unit will serve one
residence or several home units or townhouses, or larger
facilities. Upstream from the grinder pumps, gravity house
drains from within the residence are no different from any
other system, except much shorter.
The Street Main Pressure
Network
The polyethylene pressure pipe network is usually
installed in the road reserve. The network is completely
sealed through
the use of electrofusion welding techniques for jointing,
thus eliminating infiltration and inflow.
The Grinder Pump
The E/One grinder pump grinds the sewage
and discharges a finely ground slurry into the small-diameter
pressure piping. The
semi-positive displacement pump in the grinder pump station
is the best type of pump for successful parallel operation
of many pumps into a system of common pressure mains. The
pumps do not have a single fixed “operating point”,
but must operate consistently over a wide range of heads
that are continually, and often rapidly, changing. The maximum
desirable pumping head is 45m.
The Grinder Pump Unit
A grinder pump unit consists of a grinder
pump, tank, alarm panel and connecting cable. The gravity
pipework upstream
and the pressure pipework downstream connect to the grinder
pump unit, with electrical connection also required.
System
Operation
In operation, the grinder pump station will handle
sewage and many items that should not, but often do, appear
in domestic
wastewater. For example, plastic, wood, rubber and
light metal objects can be routinely handled without jamming
the grinder or clogging the pump or piping system. Transporting
sewage several thousand metres to a discharge point at a
higher elevation is possible as long as the sum of the static
and friction losses does not exceed the desirable design
limit of 45m.
Target Market Water authorities around Australia are addressing
the backlog of unsewered properties in their areas of operation
to provide
them with sewer service. This septic tank replacement
effort has gained considerable momentum in recent years.
Accordingly, the standard approach for sewering communities
with gravity sewers is increasingly being found to be a
more expensive approach.
In addition to backlog sewerage, developers
are also beginning to recognise the advantages of pressure
sewer for new developments
as well.
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Completed installation |
Where pressure sewer systems are best used
To protect sensitive
environmental areas:
- Areas with significant underlying rock
formations
- Flat sites
- Hilly or difficult terrain including islands
- Sites with high
water table
- Areas remote from existing infrastructure
- Low density housing
areas
- Where avoiding infiltration and inflow is critical
- To avoid
numerous standard pumping stations
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