Author: Rakesh Shah
Degree: Master’s in Environmental Engineering
Institution: IOE, Pulchowk Campus, Tribhuvan University
Submitted: [2024]
Status: Currently unpublished by university
Published Article: Link
Abstract
Access to clean water remains a critical challenge in underdeveloped and developing regions, where suction hand pumps are a primary means of water extraction from shallow water tables. This study investigates the performance and suction limits of No.6 hand pumps under varying operational parameters, encompassing both controlled model settings and actual field conditions. Existing literature provides varied values for these limits, lacking correlation with different operational parameters. In Birgunj, No.6 Hand Pumps are common, making it important to understand these suction limits for continued and effective use. Birgunj, Nepal, an area heavily reliant on hand pumps, the research examines the influence of parameters (model/field condition, suction head, stroke speed, pipe diameter, and length) on discharge and volumetric efficiency. The findings demonstrate a significant impact of operational conditions on pump performance, with discharge and volumetric efficiency highly dependent on the tested parameters. Notably, the practical suction limit observed in field conditions (21.0 feet) is lower than in model tests (26.5 feet) for the same 1.5-inch diameter pipe, while the maximum suction limit is consistent for all cases (31.0-31.5 feet). These values represent the practical working limit and the failure point of hand pumps, providing valuable insights into their operational boundaries. Discrepancies between model and field performance were observed, with field hand pumps exhibiting lower discharge rates due to increased head losses. The use of longer suction pipes in the field further decreased peak discharge compared to shorter pipes. The static groundwater table exceeding the practical suction limits and reaching near maximum suction limits with seasonal groundwater fluctuation poses a challenge of failure in the dry season and yields lesser water discharge. This puts Birgunj in a risky situation adding that there are no groundwater monitoring systems. The findings of this study underscore the importance of considering operational conditions for optimal hand pump performance, paving the way for enhanced water accessibility in Birgunj.
Keywords | hand pump performance, hand pump failure, suction hand pumps, suction limits
Note: “This thesis includes content summarized and peer-reviewed in: [Rakesh Shah, Arun P. Parajuli, Rajit Ojha; Evaluating performance and suction limits of No.6 hand pumps with varying operational parameters. Water Practice and Technology 1 September 2024; 19 (9): 3526–3537. doi: https://doi.org/10.2166/wpt.2024.215]”.