Skip to main content

Hydraulic Energy Flushing Of Inverted Siphons

Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Abstract:

The City of Richmond, Virginia is located at the head of tide on the James River. The older central part of the City is served by a combined sewer system (CSS) that comprises about 12,000 acres. The largest basin in the system is the Shockoe Creek Basin area that is comprised of about 8,000 acres, about 2/3 of the overall system. The City began addressing Combined Sewer Overflow (CSO) control in the late 1970s by constructing a 38 million gallon “first flush” retention system on the Shockoe Creek Basin in the early 1980s. The Shockoe Creek Basin discharges into a diversion structure at the retention system through an arch sewer. A crest dam in the Outfall Structure, down stream of the Diversion Structure, prevents dry weather flow from overflowing into the river. Flows into this structure are transferred to the Wastewater Treatment Plant (WWTP), across the James River using two 66-inch inverted siphon pipelines. The siphons have a firm capacity of 200 mgd. Flows feeding the river crossing vary from a dry weather flow of approximately 30 mgd to a wet weather flow of about 60 mgd. These wet weather CSO flows are very turbulent and sediment laden. Wet weather CSO events after the winter driving season contribute large quantities of sand and grit. Over time, deposition of solids in the twin river crossing can reduce the flow capacity of the inverted siphons pipelines, reducing transfer capacity to the wastewater treatment plant. This plugging causes operations personnel to modify standard operating procedures and maintenance personnel to perform extra duties.

This paper will describe a mechanical flushing system located in the confined space of the Outfall Structure. The mechanical flushing system was designed to store and release a large volume of wastewater to flush the twin river crossing with a high volume, high velocity stream while avoiding accidental releases of dry weather overflow to the river. The design also allows safe operation under extreme high flow conditions. The flushing system will be utilized during dry flow however; flows can increase rapidly thus requiring safe external operation.

Document Type: Research Article

DOI: https://doi.org/10.2175/193864701790902077

Publication date: 2001-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more