Investigation of the Potential of Dolomite and Calcite Rocks for Improving Drinking Water Alkalinity

Groundwater remains a major source of drinking water in many developing countries; however, its quality is often compromised by low pH, poor buffering capacity, and undesirable sensory characteristics that limit consumer acceptance. This study evaluated the potential of calcite and dolomite minerals as natural, low-cost amendments for improving the chemical stability and organoleptic quality of groundwater over residence periods of 30, 60, and 90 days and application rate of 5 g/L. Untreated groundwater served as the control, while treated samples were analyzed for pH, total alkalinity, and sensory attributes including taste, odor, and color. Data were subjected to one-way analysis of variance (ANOVA), and treatment means were separated using Duncan Multiple Range Test (DMRT) at p < 0.05. Results indicated a significant increase in pH for mineral-treated water compared with the control across all residence periods. Calcite treatment produced the highest pH values, increasing from 7.32 at 30 days to 7.82 at 90 days, while dolomite increased pH from 7.05 to 7.71 over the same period. Total alkalinity also increased significantly, with dolomite exhibiting a stronger long-term buffering effect, reaching 121.40 mg/L after 90 days. Organoleptic evaluation conducted by 15 panelists showed that treated water samples recorded significantly higher preference scores for taste, odor, and color than the untreated control. Calcite-treated water consistently showed slightly increased sensory scores, though both minerals performed comparably. The ANOVA and DMRT results confirmed that mineral type and residence time significantly influenced groundwater quality parameters. The study demonstrates that calcite and dolomite are effective and sustainable materials for improving groundwater alkalinity and sensory acceptability, offering a practical solution for decentralized drinking water treatment in resource-limited settings.