Design, construction and performance of a horizontal
subsurface flow wetland system in Australia
Lise M. W. Bolton and Keith G. E. Bolton
ABSTRACT
Malabugilmah is a remote Aboriginal community located in Clarence Valley, Northern NSW, Australia.
In 2006, seven horizontal subsurface flow wetland clusters consisting of 3 m × 2 m wetland cells in
series were designed and constructed to treat septic tank effluent to a secondary level (Total
Suspended Solids (TSS) < 30 mg/L and Biochemical Oxygen Demand (BOD
5
) <20 mg/L) and achieve
>50% Total Nitrogen (TN) reduction, no net Total Phosphorus (TP) export and 99.9% Faecal Coliform
(FC) reduction. The wetland cell configuration allowed the wetlands to be located on steeper terrain,
enabling effluent to be treated to a secondary level without the use of pumps. In addition to the
water quality targets, the wetlands were designed and constructed to satisfy environmental,
economic and social needs of the community. The wetland systems were planted with a local
Australian wetland tree species which has become well established. Two wetland clusters have been
monitored over the last 4 years. The wetlands have demonstrated to be robust over time, providing a
high level of secondary treatment over an extended period.
Lise M. W. Bolton (corresponding author)
Keith G. E. Bolton
Ecoteam 43 Ewing Street,
Lismore,
NSW, 2480,
Australia
E-mail: lise@ecoteam.com.au
Key words | aboriginal, constructed wetland, Melaleuca, paperbark
INTRODUCTION
Malabugilmah is an Aboriginal community located in Clar-
ence Valley in Northern New South Wales, Australia,
approximately 85 km north of Grafton. The village has a
population fluctuating around 80 people, and consists of
17 houses and two community buildings. In 2006, seven
horizontal subsurface flow (HSSF) constructed paperbark
wetlands were built to treat septic tank effluent from Mala-
bugilmah to a secondary level before reuse onto a football
field. Constructed wetlands provide an effective low cost
and low maintenance system for the treatment of domestic
sewage of rural communities (Coleman et al. ; Manios
et al. ). HSSF constructed wetlands have been used to
treat a variety of wastewaters worldwide (Vymazal et al.
). They have the added benefit of reducing human con-
tact with wastewater, avoiding the breeding of mosquitoes,
and are less climate and temperature sensitive when com-
pared to free water systems (US EPA ; Kadlec &
Wallace ; Kadlec ). Melaleuca (‘paperbark’) trees
were planted in the wetlands on the basis of their demon-
strated ability to thrive in nutrient-rich and waterlogged
conditions (Bolton & Greenway ) and excellent pollu-
tant removal capability (Bolton & Greenway ; Bolton
).
The constructed wetlands were built to improve detrimen-
tal human and river health impacts caused by the previous
failing sewage system. The treatment system was designed to
meet Australian secondary treatment standards (AS/
NZS:1547 ) with target water quality parameters
<20 mg/L Biochemical Oxygen Demand (BOD), <30 mg/L
Total Suspended Solids (TSS), and design goals were set for
50% Total Nitrogen (TN) removal, 0% Total Phosphorus
(TP) removal (i.e. no phosphorus export) and 99.9%
removal of Faecal Coliforms (FC), within a 12 month estab-
lishment phase. The wetland project additionally aimed to
satisfy the social, economic and environmental needs of the
community. The community was engaged at all stages of plan-
ning and design, and 14 community members were employed
and received on-the-job training during construction. Com-
munity members continue to be trained and employed to
operate and maintain the sewerage treatment system.
DESIGN AND CONSTRUCTION
In 2004, Ecoteam convened a brainstorming session with
the Malabugilmah community which identified a number
1920 © IWA Publishing 2013 Water Science & Technology | 68.9 | 2013
doi: 10.2166/wst.2013.434