Leaching Potential and Effectiveness of Pervious Mortar Filters in Bacteria and Turbidity Removal from Surface Water

A pervious mortar filter (PMF) is a modification of pervious mortar and pervious concrete designed as a water filter that, based on its physical characteristics, can reduce turbidity and bacteria. However, chemically, it contains minerals that can dissolve upon contact with water and be found in effluent. This study aimed to determine the performance of PMF in treating surface water by reducing turbidity and Escherichia coli and to assess its leaching potential. PMF specimens were created by mixing sand (0.6– 0.85 mm), cement, and water with sand-to-cement ratios (M) of 4 and 5 and a water-to-cement ratio (w/c) of 0.4. Each mixture was then molded into pipes with a diameter of 8.2 cm and different thicknesses: 3, 5, and 10 cm. Raw surface water was used for the performance and leaching tests. Results showed that PMF effectively removed 95% turbidity and 99.71% E. coli, which increased with the filtration duration. PMF reduced E. coli more effectively when designed with a thickness of 10 cm than 5 or 3 cm because it would provide more surface areas for suspended solids and bacteria to attach and be retained. More substantial increases (mean %) of pH, hardness, calcium ions, and TDS were observed in PMF M4 with a thickness of 10 cm than in thinner ones because it contained more cement that would dissolve when in contact with water.