Sedimentation tank design for rural communities in the hilly regions of Nepal

Abstract

Mathillo Semrang in rural Nepal relies on stream sources to provide drinking water. Erosion and deforestation of local terrain produces turbid water that requires treatment before distribution. The round gravity sedimentation technology currently employed is large in footprint and cannot handle large increases in influent flow rate and silt concentrations resulting from extreme weather events. In partnership with Nepal Water for Health (NEWAH) and Engineers Without Borders Australia (EWB), this project aimed to design a highly simplified, small footprint inclined plate settler (IPS) to treat influent flow-rates ranging from 0.25 to 4 L/s. A 76 % decrease in footprint was achieved by the IPS design for source flow-rates up to 4 L/s. Laboratory analysis revealed that a large inlet area along with a highly sloped floor is essential to the design which may prove problematic in the reduction of footprint in the design. Further research is needed to confirm this finding along with further collaboration with rural Nepalese communities and NEWAH.