Water Kit - Hunter Water

3.4 morpeth wastewater & wetlands
Wastewater to wetlands
The decommissioned treatment ponds
at the old Morpeth WWTW have been
transformed into a wetland sanctuary for
local and migratory birds.
The original WWTW was constructed in
1940. During 2001 a new $20M treatment
works was constructed to cater for
population growth in the area and reduce
nutrients entering local waterways.
The old plant’s maturation ponds have been
converted to wetlands
The WWTW used a series of shallow
ponds to allow direct sunlight to kill
bacteria in the effluent. The new facility
uses artificial ultraviolet light in a
disinfection tank.
During planning for the new treatment
works, Hunter Water became aware
that the old maturation ponds had
An aerial photo of the new Morpeth WWTW
and wetland sanctuary
become habitat for local and migratory
birds. With this knowledge Hunter
Water committed to retain the open
water ponds and rehabilitate them as a
wetland area for birds.
The rehabilitation project
Over 100 tonnes of concrete and soil
waste were recycled on-site instead of
being disposed to landfill. This recycling
involved the creation of beaches, islands
and shallow ponds to attract a variety of
wading birds.
The rehabilitated wetlands generated
great interest among bird watchers
and the local community. A team of
environmental workers and Hunter Water
employees planted hundreds of native
trees and shrubs around the wetland. The
aim was to recreate a ‘natural’ wetland
ecosystem.
High quality treated effluent from the
new plant is only pumped into the
wetlands when natural water levels fall
too low to sustain the ecosystem. This
constant source of water has supported
the survival of local and migratory birds
during periods of drought.
Treating wastewater at Morpeth
Morpeth WWTW serves about 50,000
people who live and work primarily in
Morpeth, Metford, Thornton, Tenambit,
Ashtonfield, Beresfield and East Maitland.
The WWTW has the capacity to treat an
average flow of 14 million litres per day,
or about 60,000 people. The facitility has
the capacity to be upgraded to serve
80,000 people in the future - subject to
planning approval.
The new plant was built to minimise
impacts on the surrounding environment.
Wastewater is collected from houses and
industry via pipes and pumping stations,
and treated to a high standard that
includes a disinfection stage.
The final treated effluent is recycled where
possible or otherwise discharged into
the Hunter River. During dry conditions
some effluent is diverted to the wetland
ponds. Recycled wastewater is used to
irrigate golf courses and woodlots. The
remaining sludge (solids) is treated and
dewatered to become biosolids, and
reused in agricultural activities and mine
rehabilitation on the site.
Protecting the Lower Hunter catchment
By 2006 all of Hunter Water’s WWTWs
will have been completely upgraded.
The focus of these upgrades, which in
turn reduces negative impacts on local
waterways where effluent is discharged.
In achieving higher levels of treatment
however, some trade-offs have had to be
made, including:
• higher costs for construction and
operation of new plants compared
to older plants
• more atmospheric emissions from
power stations associated with
higher power usage at plants
• increased transport needs through
recycling greater quantities of
biosolids
A water quality report on the Hunter
River indicated that lowering nitrogen
and phosphorus levels in effluent would
protect and improve downstream water
quality. Levels of nitrogen have been
reduced from 15 to 7 milligrams and
levels of phosphorus reduced from 6 to 3
milligrams per litre.
Reductions in phosphorus and nitrogen
beyond this, however, were considered
to be of little impact as Morpeth WWTW
only contributes 2% to 3% of the total
nutrient load in the river.
Water kit . ssS . 001 . april 2010
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