Environment in the district of Gia Lam
Pilot project for a decentralized water treatment plant
To provide
a solution to the issue of residential wastewater disposal without treatment, IMV has proposed to carry out a treatment adapted to the context of suburban houses in Kieu Ky. The studies were conducted in 2008 by East Vietnam and the german NGO Borda. The technology consists of an aerobic and anaerobic treatment by bacteria, then by plants.
Requested by the IMV, the Asian Development Bank has provided financing for studies and works.
In May 2008, Kieu Ky commune made a plot of land available
to the project. The work was done in November and December 2008 and the station
commenced operation in early January 2009, with the capacity of treating
wastewater from 60 households in the commune.
After one year of use, the Kieu Ky separate sanitary
system encountered a number of problems due to the lack of difference in ground
level. Such a system requires a slope of at least 1 percent. For this
reason, it was not possible to hook up some of the households, resulting in a
less-than-optimal operation of the system.
Moreover, the flow from the separate system at the DEWATS intake port increased
drastically with thunderstorm rainfall. Rainwater poured into the separate
system through inlet openings resulting from unauthorised hook-ups made by
local residents themselves. This water overwhelmed the treatment plant and
reduced its performance.
IMV was asked to do a study to find solutions to this
problem as well as to find a way to link in the entire catchment area of the
treatment system. The local residents had asked to have the system extended
throughout the neighbourhood.
The technical study was done between July and
September 2010 by EAST with the assistance of a Vietnamese engineering student at
INSA-Lyon recruited by IMV. The study concluded that the idea of a separate
sanitary system had to be abandoned and that the existing combined sewerage
system should be used. This network had been installed back in 2006 to collect
both wastewater and rainwater from the entire catchment area.
In October 2010, the combined unit and the DEWATS were
connected by putting in a new conduit channel equipped with a trash rake in
order to keep solid waste from getting into the treatment system. A storm
overflow structure was also added to prevent overloading the system during rain
storms.
However, the functional parts of the combined
wastewater system that were built at the same time as the treatment plant were kept.
This means that wastewater from all of the households in the catchment area
hooked up to the system flows into a functional network (both combined and
separate), converging in the DEWATS.
EAST is now working on setting up a long-term
management programme for the treatment system with funding from the Asian
Development Bank. Maintenance is expected to be handled by Gia Lam District Sanitation
and Environment Department and funded by means of fees collected from the
villagers in connection with waste collection.
EAST rounded out the programme by conducting
demonstrations of sanitary drainage system upkeep for the residents directly
responsible for the network that is as close as their front doorsteps. The demonstrations
aimed to raise awareness of the members of the community regarding the simplicity
of the operations as well as their necessity. As a result, the system has been
cleaned regularly ever since.