Browsing by Author "Jayawardena, N.K.R.N."

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    Removal of Excessive F-, Mg2+ and Ca2+ in Groundwater by Electrolysis
    (Uva Wellassa University of Sri Lanka, 2018) Jayawardena, N.K.R.N.; Amarasooriya, A.A.G.D.; Weragoda, S.K.
    Groundwater contamination in North Central Province, Sri Lanka by excessive fluoride (F), magnesium (Me) and calcium (Ca2+) causes many negative health effects to the consumers. Though many technologies are available to remove F-, Mg2+ and Ca2+, installation and maintenance cost, power consumption, expertise knowledge, output water quality and the water rejection have become bottle necks on providing the safe water. Electrolysis has proven as a cost effective method. Therefore, in this study, electrolysis was investigated to remove F-, Mg2+ and Ca2+ ions. As an electrolysis reactor, a Polyvinyl Chloride material made rectangular box, which was separated from a clay membrane was utilized by employing platinum and stainless steel electrodes. Electrolysis was performed by varying Coulombs (Ampere x second รท Liters) per Liter (C L-1) for groundwater samples collected from North Central Province. During the electrolysis, contaminants were removed via forming a white colored precipitation in the cathode bath and transportation by coulomb forces towards the anode bath. The total water recovery by the system was 50%. Analytical results showed that significant amount of hardness species (Ca2+ and Mg2+), HCO3- and F- can be removed. The precipitation could be a mixture of CaCO3, MgCO3 and Mg(OH)2 which formed by reacting HCO3- and OH- ions with Ca2+ and Me. Fluoride could be removed via coprecipitation with Magnesium hydroxide. Moreover it was identified that current supplied has a positive effect on hardness species and F removal. The maximum removal percentage was 71.6% for the Mg2+ at 1000 C L-1. The Ca2+ and F- removal observed were up to 94.45% and 39.79% respectively for the 1000 C L-1. There was no significant effect on removal percentages by the initial concentration, but the higher the initial Me2+ and Ca2+ concentrations, the higher the removals of Mg2+, Ca2+ and F. Accordingly, household scale treatment system was designed and proposed.