Keeping Watch

An integrated software program helps the Des Moines Regional Wastewater Reclamation Facility find savings opportunities and extend equipment life
Keeping Watch
Cogeneration accounts for up to 40 percent of the energy needs of the Wastewater Reclamation Facility in Des Moines. Capacity will increase to more than 50 percent when more engine-generators are added in the near future.

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It is said that problems demand solutions. The corollary to that old rule is that solutions demand information; the deeper the understanding, the better the solution.

The staff at the regional Wastewater Reclamation Facility run by the City of Des Moines, Iowa, now has extensive knowledge of the plant’s energy and maintenance needs through innovative software. The program is tied to the SCADA system to show where energy is being used and identify ways to optimize equipment.

The Enterprise EAM Asset Sustainability Edition (EAM-ASE) is from the Infor business software company. Des Moines received an $83,225 federal stimulus fund grant from the Iowa Office of Energy Independence to integrate the program with its Rockwell SCADA, Hach water information system, and ControlLogix PLCs (Rockwell Automation).

It monitors the performance of motors, pumps, and blowers and tracks energy use parameters to aid in cutting energy consumption at the plant.


Real-time data

“It enables us to monitor in real time the key operating parameters and health statistics for the plant’s major pieces of equipment,” says Bill Miller, who headed up the project for the plant’s facilities management group. “The ability to view and manage the total operating condition, including energy usage, operating costs, and maintenance costs, allows us to optimize the use of these high-cost assets, minimize the impact on the plant, the environment and the public, and extend the life of our equipment.”

The software project, which went online on January 1, 2011, received the 2010 Governor’s Special Recognition in Energy Efficiency/Renewable Energy Award. The 200 mgd (design) facility serves 16 communities and sewer districts in the Des Moines Metropolitan Wastewater Reclamation Authority with a population of more than 560,000.

With the help of Stratum Consulting Partners, the plant team used the software to create a monitoring and maintenance program for its largest energy users, including four 2,000 hp aeration blowers, six 700 hp pumps, and nine 100 hp sludge return pumps. Projections showed an estimated savings of $41,500 a year in energy, maintenance and repair costs, and a reduction of CO2 emissions of about 1.5 million pounds.

Within six months of implementation, the actual energy reduction was about 100,000 kWh, and the annualized savings of about $200,000 were more than four times the original projections. Because of its success at the Wastewater Reclamation Facility, the city’s water works staff has decided to use the software as well.


Ranking equipment

The data from the new system also helps the operators know which equipment is most efficient, and that helps them decide which pieces to use first. Some of the 2,000 hp blowers, for instance, are more efficient than others, so operators use them as the primary blowers.

Two SCADA programmers from the Des Moines wastewater utility worked with two from Rockwell International and another from Stratum to integrate the EAM-ASE and create the trending and reporting tools.

Miller is now planning phase two of the project, adding about 10 percent of the 70 pump stations to the EAM-ASE system along with more pumps, the buildings’ HVAC system, and large compressor systems. All of the equipment for a new 300 mgd headworks, to be added in about three years, will also be included.

Miller is also looking for a way to expand use of the software to the plant’s cogeneration facility, which generates 1.8 MW, or 35 to 40 percent of the facility’s electrical demand, and recovers heat and exhaust gas from its three 600 kW Cummins engine-generators to heat digesters and some buildings.

Two 1.4 MW GE Jenbacher 12-cylinder generating units will soon be added to the cogeneration system, and two others will be added as backup generators. That will increase the amount of self-generated power to more than half of total demand.


Down with carbon

“It will further reduce the plant’s carbon footprint and expand the use of renewable fuel from biogas,” Miller says. Other energy projects have included advanced energy-efficient control systems, marketing of biogas to neighboring industries, optimizing the 2,000 hp process air blowers, and the addition of energy-efficient lighting.

Miller’s expertise and passion center on managing assets over their life cycles to make things as efficient and predictable as possible. He admits it sometimes takes a change in mindset to embrace such efforts, but when data is managed and presented in ways that are usable and understandable, it makes the mundane valuable.


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