A Better World - Volume 3: Ensure Access to Water and Sanitation for All

[

] 102

A B

et ter

or ld

gent aquatic plants growing on a buoyant mat are an innovative

tool for managing nutrients in ponds, lakes and slow-flowing

waters. The system allows plant roots to grow through a float-

ing mat and into the water beneath, providing a large surface

area for nutrient assimilation, growth of biofilms and the

entrapment of fine suspended particulates. By shading the

surface and buffering water turbulence FTWs can also promote

the settling of suspended algae and solids beneath the mats.

Because the plants are grown on floating media, this type

of wetland is more tolerant to fluctuations in the breadth and

depth of water. Plant roots that hang below the mats provide

a large surface area for biofilm growth and entrapment of

suspended particles. Because the plants are not rooted in the

sediment, they are forced to obtain nutrients directly from

the water column. In addition to their pollutant removal

capability, FTWs are also useful in terms of:

• The availability of resources.

• A high reduction of BOD and solids, but low reduction of

pathogens.

• Water biota, such as water hyacinth, grow rapidly and are

visually appealing.

• A low to moderate capital cost. Operating costs can be

offset by revenue.

• The potential for local job creation and income generation.

• Can be built and maintained with locally available materials.

The project saw the installation of FTWs measuring 1 x 2

metres, each made from 3-inch diameter PVC pipe and coarse

netting. The planting medium was cocopeat – a lightweight

substance with good water capillarity, made from coconut

husk – with a thickness of 5 cm. Kale, spinach and lettuce

were planted, each having a growing period of 4–5 weeks.

These plants have been widely used in wastewater treatment,

have economic value, and are familiar to the community.

The first step in project implementation was the involve-

ment of the Kampung Tanggulan community, facilitated by

meetings and other social events. Residents were very proac-

tive in providing input at the early stage, with enthusiasm

and a willingness to participate very much in evidence. They

gave approval for the project, and voiced their expectations

for its development.

The sedimentation and shallowing due to the erosion of

the river banks and bed has necessitated excavation work

Stormwater

Control tank

(sedimentation)

River

Flows to Cikapundung

Directly used

without treatment

Treatment

system

Water gate

Cleanout

Pipelines

Cleanout

Pipelines

Primary sewerage pipe

Cleanout

Pipelines

House connections

Public toilet

Fish farm

Wastewater management system concept design

Construction of Floating Treatment Wetlands by the local community

Power plant

Image: IoT

Source: IoT