January 2008, Vol. 20, No.1

No Chemicals Required

This Minnesota plant removes phosphorus using a completely biological process

No Chemicals Required Timothy J. Block, Larry Rogacki, Christine Voigt, Donavan G. Esping, Denny S. Parker, John R. Bratby, and Jennifer A. Gruman

The Metropolitan Wastewater Treatment Plant in St. Paul was the first Minnesota plant to be converted to biological phosphorus removal (BPR) and is currently the largest BPR plant in the world. The phased conversion took 7 years and saved its customers about $100 million, compared to the original project proposal.  Read full article (login required)  


Got Carbon?

Widespread biological nutrient removal is increasing the demand for supplemental sources

Got Carbon Christine deBarbadillo, James Barnard, Steve Tarallo, and Mark Steichen

As more wastewater treatment plants are upgraded to provide biological nutrient removal (BNR), the demand for supplemental carbon and volatile fatty acids (VFAs) is growing. So, what should plant staff consider when evaluating potential sources? Read full article (login required)  



The Bottom Line

Experts evaluate the costs of municipal membrane bioreactors

The Bottom Line James DeCarolis, Samer Adham, William R. Pearce, Zakir Hirani, Stephen Lacy, and Roger Stephenson

The number and size of municipal membrane bioreactor (MBR) facilities in the United States has grown dramatically during the past decade, as has the number of municipal MBR suppliers. However, little information has been published about the cost of MBR systems. Wastewater treatment professionals need current MBR cost information for budgeting and planning purposes. They also could use data on how technological advancements and increased competition are affecting the membrane component of MBR costs, as well as insights about key factors that affect the overall cost of MBR facilities. Read full article (login required) 


Operations Forum Features

A Powerful Byproduct 

This California plant has been recovering energy from biogas since 1951

A Powerful Byproduct F. Michael Lewis, R. Tim Haug, Ali Poosti, and Kenneth R. Redd

The Hyperion Wastewater Treatment Plant in Los Angeles has been recovering energy from digester gas (biogas) for more than 55 years. Its energy-recovery techniques have included internal-combustion engines, gas turbines, staged-combustion fluidized beds, package boilers, and combustion in the boiler at a full-size electric utility steam plant. Read full article (login required)  


Greasing Digester-Gas Production 

A California city sees 50% greater gas production within a 2-year payback period

Greasing Digester-Gas Production Paul Cockrell

For many years, the City of Watsonville, Calif., operated a cogeneration system fueled by approximately equal portions of digester gas and natural gas. In 2001, the price of natural gas rose significantly, and the city commissioned a study to identify and evaluate technologies that would increase digester-gas production. Grease collected from restaurant grease traps that was normally landfilled was now sent to the digesters. The city now has over 4 years of grease-digestion experience, and digester-gas production has increased by more than 50%. Read full article (login required) 


Now With Grease-Cutting Action! 

Do grease control products really work?

Now With Grease-Cutting Action Victor Occiano, Anil Pai, Isam Hireish, Rey Sacro, and Monika Smoczynski

Responsible for sanitary sewer overflows (SSOs) in many wastewater collection systems, grease blockages may be prevented via source control, mechanical cleaning, or doses of grease-control products. Researchers recently evaluated several grease-control products and found that several treated fats, oils, and grease (FOG) effectively. Read full article (login required)