Comparative analysis of locally made filters for the treatment of grey water in rural areas

Abstract

This study compares the efficiency of two artisanal filters, made using materials readily available in rural areas lacking drainage systems, which necessitate the treatment of greywater to prevent contamination. The objective was to determine the filters' efficiency based on the type of filtering material, specifically: 1) sand, gravel, activated carbon, and fresh pine shavings; and 2) coconut husk. The efficiency was determined by measuring the chemical oxygen demand (COD), biochemical oxygen demand (BOD), nitrites, nitrates, phosphates, apparent color, true color, suspended solids, and turbidity in both the influent and effluent of the filters. For this study, the filters were constructed in a community located in El Paraje de Choquixcabel, in the municipality of Santa Lucía Utatlán, Sololá, Guatemala. Greywater generated from laundry and showering activities was used during the evaluation. A total of 12 samples of influent and effluent were collected throughout the study. The filter with the highest efficiency, at 75% removal of physical parameters, inorganic non-metallic compounds, and aggregated organic matter, was the one using fresh pine shavings as the filtering bed, although its performance was not consistent. These filters showed significant variability in results, primarily due to the storage time of the water in the filter container, a consequence of the time needed to collect water in the household.