Report Number: 91
Year: 2001

Assessment of Turbidity in the Geus River Watershed in Southern Guam

This report presents the results of a collaborative pilot study between University of Guam Water and Environmental Research Study and the Kosrae State. The objective of this study was to determine the feasibility of slow sand filtration technology in treating surface water resources on Kosrae, the easternmost state of the Federated States of Micronesia. The pilot facility constructed on Kosrae consisted of four filters; two filters with locally manufactured filtration media and two packed with imported sand specially formulated for slow sand filtration. The goals of the study were to determine: 1) if locally crushed basalt media exhibited the same bacteria and turbidity removal efficiency as imported media, 2) the run lengths associated with both types of media when an hydraulic loading rate (HLR) of 0.2 m/hr was used and, 3) to determine design criteria for the construction of full-scale facility. The study revealed that in mature filters, 1) fecal Coliform removal exceeded 2-log cycle (over 99%) and, 2) turbidity removal appeared similar. Significant differences in tail water pH (8.3 for local media; 7.6 for imported media), and filter run lengths were observed.

Shahram Khosrowpanah
Leroy Heitz
Colette G. Beausoliel