It was the vision of the legendary king, Maha Parakumba who was renowned for his miraculous work in
water management in the 11th century.. Water is life,.. it is precious to all living
beings and we all depend on it every day.. Just imagine standing in a dry, hot
day under the summer sun, without water even for a few minutes.. !!
It is the duty of mankind to protect the clean water and if
possible preserve the re-usability of polluted water. In our visit to
Raddolugama Water Treatment Plant & Sewage System, we saw it does an
exemplary job in the above regard.
The Water Treatment Plant & Sewage System was established
in 1987 to supply drinking water to the housing scheme in the area. Later, a second
water treatment plant was put up after the tremendous success had with the
first one. Both to are fully functioning at present, though they have a few differences
in their water treatment mechanisms. It supplies over 4500m3 of
water per day to nearly 5000 houses, Police Station and Army Base at Seeduwa,
Wijaya Kumaratunga Memorial Hospital and Katunayaka Industrial Zone.
Treating Water is a multi-step process –
- First, water is pumped to the site from the water resource (Dandugan Oya).
- Then this water is aerated. Mixing with the atmospheric O2 helps in the oxidation of irons and other harmful particles and breaks them down. During aeration Alum (Aluminium Sulphate ) and Lime (Calcium hydroxide) is added. Alum combines with mud particles and form floccules while Lime helps in raising and maintaining the pH around 7.0.
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| Aeration of water |
- Then the water slowly flows into sedimentation tanks where the mud floccules sink and collected in the bottom.
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| Sedimentation tanks |
- Then the mud free water enters the filtering tanks which are composed of layers of rocks arranged according to size. Water seeps through this and small particles and parasites are retained. There is a process to clean these filters by pumping air and washing when they get blocked.
- Filtered water is then stored in large tanks and Chlorine gas is bubbled. Then clean water is pumped to regional tanks and houses.
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| Chlorinated water is pumped at the end |
Quality control is a part of the process where water is
checked for BOD, COD, E.coli and organisms once a fortnight. pH and the
chlorine concentration is checked and maintained at 7.0 and 0.2mg/L
respectively.
Sewage and kitchen waste is treated and disinfected before
releasing in to the river. It is ensured that standard BOD and COD levels are
achieved when they are released back.
Sewage system is also a multi-step process somewhat similar as the
water treatment plant-
- Houses in the scheme are positioned as twins. Sewage from a par collects small gullies and then to large gullies and into sewage well. This is pumped to grid channels and ultimately ends up in the aeration tanks.
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| Aeration of Sewage |
- Mechanical aerators mix the sewage with air and this accelerate the action of decomposing bacteria on the sewage.
- Then this go to the tanks where sedimentation take place
- Finally, bleaching powder is added and chlorinated. The degraded material is dried under the sun and is used as fertilizer while the remaining disinfected water is released back to the river.
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