Data Driven

Colorado Springs Water Utility keeps energy costs down by using automated systems to predict water demand, identify efficient processes and maximize off-peak pumping.
Data Driven
Steve Aumiller, left, and Ron Smith are operating the entire CSU water system.

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For the last 15 years, the city of Colorado Springs has used automated control systems to help system control operators see the big picture and make operational decisions with energy efficiency in mind. Using detailed data and accurate forecasting, operators take control over the entire water system and can significantly reduce energy costs with efficient operations and off-peak pumping.

The city, at the base of Pikes Peak in the eastern edge of the Southern Rocky Mountains, takes advantage of gravity to move snow-melt-sourced water from 27 reservoirs in the mountains to six treatment plants through 300 miles of raw water transmission pipeline. As needed, the city pulls up to 2 mgd from two groundwater wells. Forty pump stations and 2,000 miles of pipeline distribute processed water to a population of 425,000, in Colorado Springs and three nearby communities.

The six treatment plants have a total capacity of 232 mgd. Average peak processing is 182 mgd, 150 mgd in summer and 50 mgd in winter. The conventional treatment plants use coagulation, flocculation, sedimentation, filtration and disinfection. Colorado Springs Utilities Water Treatment Section employs 45 people for operations, maintenance, instrumentation and control; its annual water treatment budget is $5.5 million.

Operators in control

The water treatment plants are highly automated and fully integrated into a single control system. Operators can view data remotely from a laptop, which means fewer staff members are needed on site during nights and weekends. The SCADA system collects data so that system control staff can monitor the entire system, from the raw water reservoirs to the treatment plants and distribution system. Team members use that data to make 24-hour forecasts of water demand.

The analysis includes looking back at data from previous years and considering city-imposed watering restrictions. With a 10-year bank of historical data, the system control operators’ forecasts are highly accurate. A benefit of forecasting is minimizing flow changes at the plants, which can surge the filters, use unnecessary electricity and upset the treatment process.

“If a plant’s flow changes from 30 mgd to 60 mgd, it might knock out a filter for a while and require additional filter washing or more turbidity pushing through a filter,” says Jeff Crockett, water treatment manager. “Before we had access to in-depth system data, our operators might have made five flow changes in the plant every day. Now with our 24-hour forecasts, our treatment operators know what levels the plant should treat for the entire day, so if they make a flow change, it will be a small one.”

Forecasting also allows for staff to reduce pumping costs by filling tanks in off-peak hours when electric rates are lowest. Operators have experimented with different time frames to withhold washing filters until off-peak hours, while still optimizing processing effectiveness. “It’s hard to do off-peak pumping in summer when flows are high,” Crockett says. “But operators did some trial and error in spring and fall by holding off a certain number of hours to wash a filter. We did a lot of experimentation and spent a lot of time figuring out how to make it work.”

A new 50 mgd water treatment plant and delivery system are under construction and will be online in 2015. The new system will include 60 miles of pipeline, three pump stations and a reservoir that takes source water from the Arkansas River. The new plant has energy-saving design features beyond high-efficiency pumps and motors. For example, the raw water holding tanks are oversized so that they can be filled off-peak.

Armed with data

Although today’s technology automates treatment plants, operators are still important for making many decisions throughout the day, including those that take energy-efficiency into account. Real-time data helps operators to make better choices. “System control operators can see the reservoir levels and which pump stations are running,” Crockett says. “They can see in real time how turning on a particular pump will affect the cost of the system. They can decide whether to turn on that pump at that time or not. The data gives them a really good idea of how every piece of equipment affects the overall system and overall costs.”

In the coming years, Colorado Springs will update its entire water treatment system so that real-time data is more accessible than ever. All operators and mechanics will be issued iPads that can access the SCADA system, so that they can continue to remotely control the plants. They will have access to operation and maintenance manuals and drawings for any part of the plant. Equipment will be tagged with quick-response (QR) codes so that staff members can scan the code with the iPad and quickly bring up the data history of any device for analysis and condition assessment.

“Staff will be able to pull up information on a particular motor, look at the vibration data and spot a problem sooner than we normally would,” Crockett says. “Having this level of data at their fingertips will allow them to make quicker, better decisions.”

Keeping customers in mind has been the driving force behind the energy-efficient philosophy at Colorado Springs Utilities. “Sustainability is very important to us,” Crockett says. “We are the stewards of our ratepayers’ dollars, and we have an obligation to provide the highest quality water at the lowest possible cost. I always tell our operators that these are our ratepayers’ treatment plants, and we have to treat them as such. We are the stewards of their utility system.”


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