Grit Transport in a Force Main with Adverse Slopes

This paper describes methods for calculating the maximum diameter of grit particles that could be transported through a force main with adverse (e.g., steep to vertical) slopes by varying the slope, diameter, and thus the associated velocity that can be achieved in the force main. These analysis methods are derived from sediment transport theory and do not rely on the rule-of-thumb velocity criteria or empirical observations that are typically used to estimate grit transport in force mains. The approach is generalized such that particle characteristics (sphericity, density) and fluid characteristics (viscosity, density, fine sediment concentration) can be specified. To demonstrate application of the proposed methods, the results of a grit transport hydraulic analysis are presented for a segment of an approximately 4.6 mile long, up to 64-in. diameter CSO force main with adverse slopes that will convey a maximum of 110 MGD of wastewater. This paper also discusses design features that encourage the transport of grit particles through force mains and minimize deposition.


  • English

Media Info

  • Media Type: Web
  • Features: References;
  • Pagination: pp 583-593
  • Monograph Title: Pipelines 2014: From Underground to the Forefront of Innovation and Sustainability

Subject/Index Terms

Filing Info

  • Accession Number: 01536282
  • Record Type: Publication
  • ISBN: 9780784413692
  • Files: TRIS, ASCE
  • Created Date: Aug 4 2014 3:01PM