Abstract:
Eastern Coastal Towns of AmparaDistrict(ECTAD) Water Supply Project has been
planned to implement in two phases. The first phase of the project, having capacity of
17,500 t:/day was commissioned in June 2001 The second phase was commissioned
in June 2007 and it has a capacity of 72,000m:/day. In phase I the treatment process
in the plant consists of Coagulation and Flocculation,Dissolved Air Flotation (DAF),
Rapid Sand Filtration, Post Chlorination,ph Correction and Sludge Treatment. The
treatment process for the phase II is the same, except for pre- chlorination and addition
of powdered activated carbon (PAC)at the flash mixer. The scheme serves the Ampara
Township, too.
The first recorded water quality issue of coloured water, bad smell and taste were
raised by consumers in the year 2004. From 2004, sporadic complaints from
consumers were received and steps were taken to flush the pipelines periodically. The
regular water quality tests had not revealed the cause for the problem and a series of
studies have been carried out and various reports have been submitted. However, the
water quality issues still persist.
Therefore, four numbers of trials were carried out for collecting the samples to identify
the reason for the colour problem with following conditions at the various location of the
treatment processes such as the rapid mixing, before DAF,after DAF(floated water),
filtered and treated water.
> With pre chlori nation and with PAC,
> With pre chlori nation and without PAC,
> With out pre chllorination and with PAC
> With out chlorination without PAC
Water samples were collected at various location of the treatment processes like, rapid
mixing, before DAF,after DAF(floated water), filtered and treated water. The water
samples were tested at NWSDBAmpara,University of Moratuwa and NWSDB central
laboratory for parameters such as total iron, dissolved iron, total manganese, dissolved
manganese, total organic carbon and chemical oxygen demand.
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