Abstract:
January 2010.
The main function of this plant is to treat raw water abstracted from the Mahaweli Ganga
(River). This plant is designed to produce 35,000 m /day of drinking water. The water treatment
facilities comprise: 1) Intake section, 2) Treatment processes, including aerator, lime and alum
feeding, pulsators, sand filters, backwashing system, post chlorination and neutralization
system; 3) Storage; 4) Sludge Treatment; and 5) Other accessories, including supervisory
control and data acquisition (SCADA), programmable logistic controls (PLCs). The possible
effect of water chemistry on in-situ deposition of mineral phases at KSWTP has been analyzed
in this study. Brownish black color depositions are found inside the casing, impellers and on
the surface of the moving parts of the Non Return Valves (NRV’s) at KSWTP. Water in the
channel at the service outlet of instrument is black color. It is also noticed that black–brown
color deposition on walls of clear water reservoir. Dissolved elements such as Mn, Si, Al, Ca,
and Mg in natural water form mineral deposition with different temperature and pressure. Thus,
these elements may be causative factors. Deposition results when dissolved ions in the water
exceed the solubility of a given mineral (Sly et al, 1990).
Methodology
Deposit samples were analyzed using Energy Dispersive X-ray Fluorescence (EDX) method
which can directly determine the metal content in the solid material. Wet samples were analyzed
to determine the bacteriological effect of manganese deposition.Water quality of different
treatment processes was measured each week during the month period. Chemical water quality
parameters were analyzed using various analytical methods. Major and minor ions were
measured using titrimetric and spectroscopic methods using Varian SpectrAA 240 AAS
available at the UvaWellassa University and as Atomic Hach DR 5000 as UV/Vis
spectrophotometer. Other physical properties were measured with standard methods. Possible
mineral phases of different ion concentration with different pressure and temperature were
stimulated using Visual Minteq software.
