Student Name(s): Nora Abbott, Sean Brown, Ann Foley

Course: CEE 211 – Research Issues in CEE

Faculty Member: Kristen Jellison

Project Details: Poster | Audio File

Project description:
Many developing countries lack the resources to purify drinking water effectively and on a full scale. As a result, people turn to technologies like the biosand filter (BSF) to produce potable water. The effective sand size (ES) and sand size distribution (represented by the uniformity coefficient, UC) used in the BSF are recognized as critical parameters in the optimal performance of the filters. The ES and the UC are calculated from a sand size distribution curve, which is generated by sieving a sand sample of known mass and recording the mass of sand that accumulates on sieves of different sizes. Because access to a laboratory balance can be a challenge when constructing a BSF in a developing region, the Centre for Affordable Water and Sanitation Technology (CAWST) has developed a field protocol for measuring the ES and UC using portable field sieves and a sand size distribution curve based on the volume (rather than mass) of sand captured on each sieve. This study compares the sand grain distribution data obtained with the conventional mass-based grain size distributions to the data obtained with the field-adapted volume-based grain size distributions for five different sand samples. To assess the performance of pilot-scale BSF columns constructed with the five samples, daily testing of flow rates and turbidity removal, and weekly testing of Escherichia coli removal, were performed. The columns that removed the most turbidity and E. coli were made with sand that did not meet the recommended criteria for ES and/or UC.