By Dr. Laura Haupert and Ron Mulford
A common challenge for wastewater treatment facilities is the ability to be fully productive while also combating odor concerns and issues. As with many facilities across the U.S., regional housing and commercial development has increased, requiring many plants to operate more harmoniously with neighboring businesses. This, in turn, has created a more urgent need for effective odor control.
Colorado Springs Utilities faced this exact scenario with its Las Vegas Street Water Resource Recovery Facility, which has been in the same location since the 1930s. As urban growth and development began to sprout up around the wastewater treatment plant over the years, there was a heightened expectation that any odor problems would be immediately countered from its commercial and industrial neighbors.
To help ensure that odor would not become a problem, the plant management team researched a number of solutions, which included covering the clarifiers and the sedimentation tanks. An effort of this magnitude would have come with a price tag in the millions of dollars.
“We clearly needed an alternative odor control solution that would both fit our budget and [be] safe for the public, environment and our employees,” said Bruce Zook, project engineer at Colorado Springs Utilities. “In addition, while most of the residential areas are further away, we needed a solution that would not have an odor impact on our commercial and industrial neighbors.”
Rather than making this type of massive investment in isolation, the plant management team sought a solution that was complementary to the organization’s green strategies. In 2012, Esource/Nielsen Company ranked Colorado Springs Utilities second in the nation amongst U.S. investor-owned and public utilities on environmental friendliness.
The plant is located near a heavily trafficked sidewalk and street with an especially long frontage on one side of the facility. As such, the plant management team needed a system that was safe for pedestrians and workers alike.
In order keep in line with this strategy and ultimately be a good neighbor, Colorado Springs Utilities decided to implement OMI Industries’ 450CFM Vapor Phase unit, which uses Ecosorb® to neutralize foul odors without the use of masking agents.
The natural solutions, developed from a proprietary blend of plant extracts, food-grade surfactant and water, is engineered to seek out and destroy organic and inorganic odors on a molecular level.
Solutions like Ecosorb are readily biodegradable by at least 60-100 percent in 28 days, which makes it safe for the environment. Specifically, Ecosorb contains no hazardous VOCs, and is nontoxic for both humans and the environment. Ecosorb has also been tested against Environmental Protection Agency (EPA) guidelines, and has received the safest possible classification.
In terms of functionality with these types of systems, the general mechanism for neutralization of odorous compounds includes adsorption, absorption, solubility enhancement, distribution constant enhancement and reactions. Odorous gases, such as hydrogen sulfide, can also be neutralized by atomization of Ecosorb, which can be applied via airborne treatment using a vapor phase system.
Essentially, the vapor phase system produces submicron droplets of the solution via a centrifugal pressure blower that intakes atmospheric air. The intake air stream is sprayed with the odor neutralizers, pulled through the blower and finally dispersed on the outlet side of the blower. Unlike atomization, no water is used in the vaporization process, only undiluted Ecosorb.
The facility also uses a wind-monitoring system that automatically powers up the equipment when the wind is headed toward a neighboring industrial and commercial complex. Conversely, when the wind is not going in that direction, the system automatically shuts down - providing considerable energy and cost-savings.
“Because of the erratic wind patterns in our region, this was a major benefit for us,” added Zook. “We are continually looking to save costs, and being able to use this system in such a flexible manner has allowed us to control odors and achieve considerable savings at the same time.”
Colorado Springs is also no stranger to harsh winters, which are common in the Rocky Mountains. January temperatures can hit lows of around 14°F, and annual snowfall can top 41 inches. With these weather challenges in mind, Colorado Springs Utilities also chose the vaporization solution because it does not use water. As a result, the outside lines do not freeze in the winter. This alone significantly cuts down on the maintenance required for water-based solutions that often cause this type of problem.
Since the system has been put into place - and when it is in use - there have been no odor complaints. In addition, Colorado Springs Utilities did not receive any complaints last summer, which is when many wastewater treatment plants have to contend with increased foul odor problems due to the heat. Lastly, the system developed by OMI Industries does not require regular maintenance, which allows Zook and his team to focus on the core operations of the facility.
Thanks to this odor control approach, Colorado Springs Utilities serves as a prime example of how a wastewater treatment facility can safely and effectively combat any odor challenge to keep everyone happy.
About the Authors: Dr. Laura Haupert is the director of research and development, and Ron Mulford is the equipment division manager, both with OMI Industries, which specializes in developing natural solutions for the treatment of industrial odors.