DESIGN OF WASTEWATER COLLECTION AND PUMPING SYSTEMS - AN OPERATOR'S PERSPECTIVE

This paper addresses real examples of sanitary sewer collection and pumping system design from the perspective of operators. For collection system design, the operation and maintenance difficulties associated with rear-yard easements are discussed, along with a method of collection system layout to minimize overall system depth and avoid drop manholes where possible. For pump station rehabilitation design, field confirmation of pumping rates is reviewed as a means to help avoid the over-sizing of pumps, alternative configurations for the design of emergency bypass piping are presented, considerations pertaining to underground valve vaults are outlined, and control panel wiring and positioning are addressed. A final example concerns the ability of a designer to help an owner standardize system layouts, pumps, valves, piping, and appurtenances, with the result that the needed inventory for parts and equipment is reduced and operation and maintenance work is facilitated. Manhole structures, gravity mains, service connections, and pump stations all require routine maintenance and repair to extend service life and assure the reliability of service to customers. These maintenance and repair tasks constitute a substantial operating expense for the system owner, and therefore the design that reflects an understanding of operation and maintenance requirements ultimately maximizes value to the owner. The ideas and participation of those who operate, maintain, and repair systems should be sought out by the designer during the planning and design phases of a project.