Optimization of Soda Ash/Lime Dosage for Underground Water Treatment in Makurdi

Abstract

The research work is on determination of optimum dosage of soda ash and lime in treating underground water in Makurdi metropolis. In carrying out the work, samples of borehole and well water from five different locations of the study area were analyzed to ascertain the level of hardness and subsequently, determine the optimum values of soda ash (Na2CO3) and lime (Ca(OH)2) that will reduce the water hardness. The locations were, North Bank, Wurukum, Wadata, High Level and Kanshio. The raw water hardness level range from 80mg/l to 200mg/l averagely, which is above WHO (2005) drinking water standards of 75mg/l to 100mg/l. After treatment, the pH was found to range between 6.8 - 7.8, while the hardness obtained ranged from 76mg/l to 100mg/l and 20mg/l to 80mg/l for borehole and well water respectively, which is slightly within the WHO (2005) standard. The optimal dosage of Na2CO3 and Ca (OH)2 were determined to be 2.4 ml each with a positive correlation of 0.90. It is recommended that, soda ash be used for the treatment of underground water hardness for safe drinking, while lime be used for other domestic purposes for cost effectiveness.