Assessing the Feasibility of Wastewater Finishing Treatment by Modified Sand Filters.

The purpose of this study was to investigate the performance of the modified biosand filtration at lab scale. The traditional biosand filter arrangement was modified adding a 2nd stage to the traditional single one. Pre-clarified wastewater first flows down through different filtration material layers; then flows upward in the second stage through other three - and finer - filtration layers including small gravel at the bottom, fine sand and small gravel again. During the experiment timespan (90 days) daily results were collected, analysed and tabled at the laboratories of the Publicly Owned Wastewater Treatment Station – Palermo, operated by AMAP. The analysis included bacteriological parameters within the standard physical - chemical measures. The removal efficiency of the Total Nitrogen and Total Phosphorus was 40 to 60%; the average for Total Coliforms and E. Coli fell between 92 and 95 %. After the results obtained, the use of the modified biosand filter technology may be highly recommended for large scale application in Countries like the Author's home country (Libya) and generally in developing countries. Maintenance procedures and a proper monitoring plan appear critical for the long-life success of this cheap process, based on local resources.