WWTP Special Projects
There are several exciting projects currently underway or planned for the future at the wastewater treatment plant.
The largest project will begin in the fall of 2012 and has the City constructing a new Headworks Building. The Headworks Building is the first step of the wastewater treatment process. As raw wastewater enters the plant influent, large debris is removed by screens and smaller debris is removed by grit basins. This debris is removed to prevent damage to downstream equipment (pumps, valves, etc.). The debris is processed by grinders and washers before it is discharged to a dumpster. The existing Headworks building was constructed in 1976 and much of the equipment, HVAC and electrical systems have reached their design life expectancy. An engineering consultant determined that the best approach to resolving reliability, maintenance, and hydraulics issues with the existing Headworks facility would be to construct the new facility.
The four primary clarifiers will be rehabilitated starting in the fall of 2012. The primary clarifiers remove a large portion of the settleable solids in the wastewater. Most of the equipment and concrete structures exist in a very corrosive environment which causes structural and mechanical deterioration that requires frequent rehabilitation.
Regulatory Compliance Project - The facility’s ammonia limits are more stringent than previous limits in a recently issued discharge permit from the State and the wastewater facility cannot reliably meet the new limits as currently constructed. The permit requires construction of facilities to meet the new limits by December 1, 2016 and an engineering planning study has determined estimated capital funding needs to meet the new limits.
Biosolids and Odor Control Projects - These projects are needed to effectively manage treatment by-products and reduce environmental impacts. The facility’s existing dewatering equipment which removes moisture from treated sludge is outdated, undersized and cannot effectively treat all biosolids currently produced. A new dewatering building with odor control will replace the existing building as recommended in an engineering report completed in 2011. The engineering report developed a long-term approach to managing our biosolids with an emphasis on updating and integrating processes, facilitating optimized and compliant operations, and planning safe and maintainable facilities.
Cogeneration Project - Cogeneration is the simultaneous production of electricity and heat. Cogeneration technologies can be employed to produce power and heat from digester gas produced at the facility. Longmont’s digester gas, which is similar to that produced by other wastewater plants, contains about 60 percent methane, 40 percent carbon dioxide and trace amounts of other substances. The methane provides the fuel for cogeneration. Wastewater treatment plants typically use the heat from cogeneration to maintain digester temperatures and meet other heating demands, such as heating buildings and use the electrical energy generated from the remaining methane to run other plant processes and offset electrical costs. The twenty year life cycle cost of installing and operating the equipment would be $1.5 million less than the cost of not installing the equipment.
Infrastructure Renewal Projects - These projects are needed to protect the City’s investment in critical infrastructure and ensure reliable treatment. The wastewater treatment plant has deteriorating process, electrical and mechanical equipment due to the corrosive conditions that exist throughout the facility. There is a constant need to replace or rehabilitate assets on an annual basis.
Design for the regulatory compliance, biosolids, odor control, cogeneration and infrastructure renewal projects are anticipated to begin in 2013. Also, City staff is in the process of preparing language for the November 2013 ballot asking Longmont citizens to approve a bond to help fund the projects.
This site was updated
September 28, 2012
City of Longmont Public Works & Natural Resources