Case study

Taking a closer look saves dollars and energy
at Carbondale wastewater plant

Treatment plant operators improve savings with new energy monitoring systems

By Suzie Romig & Heather McGregor
Clean Energy Economy News

Carbondale’s wastewater treatment plant operators use the interval data and the monthly bills displayed on the Garfield Energy Navigator website to implement more changes suggested in the energy audit.

Ralph Bryant

Town of Carbondale Utility Supervisor
Ralph Bryant
stands near an energy-intensive, 75-horsepower blower that the utility staff was able to take offline at the wastewater plant as part of ongoing improvements.
Photo by Suzie Romig

The wastewater treatment plant, the single largest energy consumer in the town government’s portfolio, had already cut its energy use by about 30 percent thanks to changes implemented about seven years ago. Now Carbondale Utility Director Mark O’Meara and Utility Supervisor Ralph Bryant have tightened the energy use screws and cut energy use by another 23 percent.

This focused attention on the plant’s operations boosted overall plant efficiency enough that the town has dropped its plans for a $15 million plant expansion. Instead, the town spent about $1.4 million on improvements that have high payback potential in energy savings. The funding includes a $500,000 grant from the Colorado Department of Local Affairs. Further capital improvements to heating and ventilation systems complete in 2012 are expected to deliver additional winter gas savings.

In addition to saving energy, the ongoing improvements at the wastewater plant have saved staff time and reduced the use of processed water. Town officials say the process has improved the quality of effluent going back into Roaring Fork River, so that a cleaner energy solution is also resulting in cleaner water.

Interval meter tracks energy use

Plant operators can track the plant’s electrical use on a daily basis now that an interval metering system is in place. An interval meter was installed at the plant in September 2009 by New Energy Technologies as part of their involvement with the Garfield New Energy Communities Initiative, now Garfield Clean Energy. The interval meter records electricity use data every 15 minutes and sends the data once a day to Automated Energy, Inc. in Oklahoma City via phone line. The interval data is then sent via the internet to the Garfield Energy Navigator website where it is charted along with other building energy data from other buildings in the region.

Plant operators can log on to the site, read the previous day’s interval data graphs and monitor the plant’s electric usage. The interval data, O’Meara said, “will show where we have aberrations in operations. Say a pump is cycling too much, it will show that.”

The Town of Carbondale, as a member of Garfield Clean Energy, also posts the wastewater plant's utility bills on the Energy Navigator for plant operators to analyze.

Energy audit targets plant upgrades

Earlier in 2009, Schmueser Gordon Meyer engineers (SGM) in Glenwood Springs conducted a comprehensive energy audit of the treatment plant. Originally SGM was called in to consult on a plant expansion. Instead, SGM engineers recommended a package of efficiency improvements.

The plant upgrades include:

  • Installing a new air diffusion system in the digesters
  • Replacing low-efficiency blower motors with high-efficiency motors
  • Rebuilding motors and pumps
  • Rerouting processes
  • Incorporating automation at key locations

“It takes a lot of energy to put in a new building, and we would have been utilizing added equipment to run the additional process,” said O’Meara. Instead, he said, “We are reconditioning the plant, similar to rebuilding an old car, and reusing a lot of parts.”

O’Meara and Bryant have also focused on education and awareness for plant operators, creating a team approach to the energy-saving goal.

Plant improvements set a new baseline for energy use

Water plant energy use

Carbondale Wastewater
Treatment Plant
2009 energy use and spending

Electricity
1.8 million kilowatt hours
$126,000

Natural gas
37,800 therms
$38,200

Total utility energy spending
$164,200

 

O’Meara said he was proud of his staff as he watched what happened over the next few months as the plant operators use the interval data and the Energy Navigator database to implement more changes suggested in the energy audit.

The operation is more efficient, and the energy use is more efficient,” O’Meara said. “The work that we are doing to change our operations has established a new lower baseline for energy use.”

O’Meara’s team of skilled operators used their upgraded plant’s new capabilities and it’s new energy data tools to achieve a 23 percent energy cost reduction. He noted that the current budget crunch is “causing people to take another look” at what they can do cut costs in utility and industrial operations.

The energy use information on the Energy Navigator is also being evaluated by mechanical engineer Mike Ogburn, who works in energy tracking for Clean Energy Economy for the Region (CLEER) in Carbondale, the nonprofit that is managing the programs and services of the Garfield New Energy Communities Initiative.

Ogburn said one of the biggest challenges in helping towns meet their energy efficiency goals is having accurate, current data to analyze.

“Towns around the region have adopted goals to save energy and to reduce greenhouse gas emissions, but measuring progress toward those goals is difficult and often not put in place as part of the energy reduction plan. Very few communities have the systems in place to track progress toward those goals,” Ogburn explained.

“Now with Energy Navigator presenting both the daily electricity usage and monthly bills, the Carbondale wastewater plant team will be able to refine their processes from day to day. They’ll be able to continue meeting water quality requirements while driving down energy costs,” he said.