Chicago’s Underground Unveiled
Faruk Oksuz and Cary Hirner
City’s tunnel and reservoir plan aims to control overflows
For the first time since Al Capone’s legacy ended, Chicago’s underground has been unveiled. The city’s combined-sewer overflow (CSO) conveyance and storage system is now in its final stretch of design and construction. The Metropolitan Water Reclamation District of Greater Chicago’s Tunnel and Reservoir Plan (TARP) continues to set precedents on how to manage CSOs effectively and improve the quality of life and the environment in large metropolitan areas. Through TARP,
the district collects the CSO and floodwaters across the city of Chicago and Cook County and serves a combined domestic and equivalent industrial user population of nearly 10.1 million. Read full article (login required)
Following California’s Lead
Dean J. Gipson
As California’s wastewater agencies seek to comply with the state’s requirements for reducing sanitary sewer overflows, collection system owners nationwide can benefit from lessons learned by their counterparts in the Golden State
Owners and operators of California’s sanitary sewers must move quickly to complete the state’s General Waste Discharge Requirements (WDRs). Adopted in May 2006 by the California State Water Resources Control Board (WRCB), the WDRs establish minimum performance standards to significantly reduce sanitary-sewer overflows (SSOs). In essence, the WDRs mandate requirements pertaining to capacity, management, operations, and maintenance for every publicly owned wastewater collection system in California.
With the regulatory clock ticking and many California agencies scrambling to comply, collection system owners and operators would do well to emulate those entities that have successfully completed all or most of the regulation’s requirements. Even agencies outside the state, however, can benefit from the experiences of their California colleagues, whose efforts offer valuable insights and lessons regarding ways to address SSOs. Read full article (login required)
More BOD Needed
George P. Anipsitakis, Harold J. Curtis, Paul A. Bizier, and Hai X. Vu
Carbon additions help a ballooning Florida facility continue to produce reusable water
Located south of Jacksonville, Fla., the Blacks Ford Water Reclamation Facility operated by JEA (formerly called the Jacksonville Electric Authority) produces effluent that meets public-access reuse standards. The suburban area is growing so rapidly that the 9-year-old treatment system, based on sequencing batch reactors (SBRs), is already on its second expansion. Changes in wastewater characteristics prompted yet another upgrade and raised concerns that the facility might have difficulty meeting its effluent nitrogen limit. Read full article (login required)
Clarifier Processes Revealed
Alonso Griborio, Paul Pitt, and John Alex McCorquodale
Next-generation modeling tool helps you get the most from your clarifier
Clarifier performance depends on several interrelated factors. Hydrodynamics, settling properties, turbulence, flocculation, and solids rheology all have an impact, as do atmospheric conditions, tank geometry, internal features, and loading conditions. While the traditional clarifier design process does not account for all of these factors, computational fluid dynamics (CFD) can.
CFD is an advanced technique for clarifier design, troubleshooting, and optimization. It uses mathematical methods — and billions of calculations — to analyze systems that involve fluid motion, mass transfer, heat transfer, and associated phenomena, such as chemical and biological reactions. Today, it is one of the most advanced and accurate ways to simulate clarifier performance. Read full article (login required) WEB EXCLUSIVE
Operations Forum Features
Getting the most out of your granular-media filter
No matter what you’ve tried, perhaps you cannot get your wastewater treatment effluent filter to operate the way it once did. Wastewater treatment involves many steps, from initial screening and grit removal through final disinfection and discharge, and each step in the process has its own unique challenges. Your media filter, no doubt, faces unique challenges. However, knowing the indications to look for, as well as tests you can perform, will help you evaluate the condition of your filter and point you toward solutions. Read full article (login required)
In Case Lightning Strikes Twice
Joseph Hurley and John Marshall
The benefits of installing an uninterruptible power supply
When lightning struck a remote water-storage tank and booster station in Forsyth County, Ga., the water treatment facility staff struck back with expert help.
On Monday, July 2, 2007, lightning struck a 5-mgd (19,000-m3/d) remote storage tank, knocking out power, shutting down the booster pump, faulting the programmable logic controller (PLC) by erasing its program, and putting out of commission the radio that was supposed to alert staff at the main plant to such problems.The station had no uninterruptible power supply (UPS) system, and the battery that was supposed to provide backup power to the PLC was dead.
With no alarm from the remote facility, the staff realized that the station was inoperative only after the water level remained static for several hours.
The strike and the plant’s response offer lessons about preventive and remedial measures that can eliminate facility downtime when such unpredictable events occur. Read full article (login required)
Sewer Corrosion Vs. Plant Permit Violation?
Ed Kobylinski, Gayle Van Durme, James Barnard, Neil Massart, and Sock–Hoon Koh
How to overcome hydrogen sulfide problems while preserving biological phosphorus removal
Odor and corrosion control in the collection system can rob a wastewater treatment plant’s biological nutrient removal system of the volatile fatty acids (VFAs) it needs to operate. At first blush, the situation seems to require a choice between
treating odors and corrosion and meeting permit-enforced nutrient removal requirements, but by knowing which questions to ask, plant personnel can find solutions that balance both needs.
This article explains how volatile fatty acid formation and hydrogen sulfide treatments are linked. It also gives advice on making the decisions needed to protect a wastewater agency’s biggest asset — its collection system — and reliably meet nutrient removal requirements as cost-effectively as possible. Read full article (login required)