Evaluating the Efficacy of Sand Filtration for Greywater Treatment: Impact of Column Length on Water Quality and Irrigation Suitability

Aims: This study explores the efficacy of sand filtration in treating greywater (GW) collected from a hostel. Methodology: An experimental setup was designed using five connected polyvinyl chloride (PVC) pipes filled with sand sourced from the Cauvery River. The GW was filtered through sand columns of varying lengths (40 ft, 60 ft, 80 ft, and 100 ft), with the filtered water analyzed for various physio-chemical parameters. Results: The results indicate that sand filtration significantly reduces the levels of total suspended solids (TSS), electrical conductivity (EC), and other anions and cations, including chloride (Cl⁻), sulphate (SO₄²⁻), and sodium (Na⁺). The pH of the untreated GW was initially alkaline but was reduced to near-neutral levels after treatment with the 100 ft sand column. Key water quality indices such as Sodium Adsorption Ratio (SAR), Sodium Ratio (SR), and Soluble Sodium Percentage (SSP) were within safe limits post-treatment, making the filtered GW suitable for irrigation. Conclusion: The study concludes that sand filtration is an effective method for treating GW, particularly when longer sand columns are used, though further research is needed to optimize the filtration process for specific contaminants.