Title
Annual Update on Wastewater Systems
Body
The board has requested a system assessment on a different utility each quarter. This quarter,
Clay Moseley, Deputy Utilities Manager for GWS Operations, will present an update on the wastewater systems: wastewater collections and wastewater treatment. Discussion includes both the physical condition and operational challenges of the wastewater sub-systems: Wastewater Collections (WC) and Wastewater Treatment (WT). Also included are recent AMT (Asset Management Team - Engineering and Operations) achievements and challenges and planned near-term future O&M Goals, Action Items and Major Projects.
The physical condition of each sub-system (WC = FAIR, WT=GOOD) has seen some upward improvements from last year’s report. This is the result of AMT goals moving into their project phase, with several of the projects being successfully completed. Project completion from both CIP and in-house Operations contribute to improvements. Large systems require multiple years of CIP and O&M improvement projects before the entire system's condition can be revised to a significantly improved status. The AMT program focuses on prioritizing the most critical issues from most impactful to less impactful.
The new White Rock WRRF is now fully functional after being put into operation two years ago. It truly is a source of pride for the DPU and the WT staff enjoy operating it. It has had a few startup issues, most of which have been mitigated by the project team, but one large issue with the sludge basin mixing pumps is still being worked on. There is an aggressive corrosion problem, the source of which is not fully understood and requires further investigation.
The Los Alamos WWTP has seen several major upgrades and replacements this past year, which has resulted in a significant improvement in its overall condition assessment. The original solids dewatering belt press has been replaced with a more modern, resource efficient screw press. The headworks fine screen was completely overhauled with new components, completed by WT in-house operations staff. This saved a tremendous amount of money that will be put toward other upcoming projects. Many of the electrical motor control modules (MCC “buckets”) have been overhauled with new components by the Water Systems Electrical Technicians (in-house), providing much more reliable operation of the various electrical motors driving pumps and process equipment. This was also originally planned to be outsourced to electrical contractors as a CIP project. The LA-WWTP will be seeing several more repair and upgrading projects over this next year through a mix of in-house projects and CIP.
The wastewater collections (WC) system continues to be the focus of aggressive O&M work and CIP upgrades and replacements. O&M work includes inspections, mainline flushing, root removal, chemical treatment, and lift station service. The CIP projects will see a shift from replacement and upgrades of the lift stations to pipeline replacements and reconfigurations. Much of the original vitrified clay pipe sewer mains are seeing condition issues that now require replacement. Additionally, the AMT has identified sewer mains that are located under homes, putting them in a higher risk category for failure that necessitates reconfiguration.
The sewer system is a mix of older original VCP (vitrified clay pipe) where the BAR (Burn Area Replacement) project did not replace the mains: North Community, Western Area, upper Barranca Mesa, Downtown and Eastern Area neighborhoods, plus older sections of White Rock; and newer PVC and PE pipe where the BAR project replaced the original sewer system, along with locations where projects have already replaced the original sewer lines, and in newer parts of town: Quemazon, Hawks Landing, lower North Mesa, lower Barranca Mesa, various areas in White Rock (anything from sometime in the early 1970s to present-day). The more modern parts of the system that are constructed from PVC and PE pipe rarely present problems in the main line, usually only where poorly constructed connections were made. VCP pipe is subject to shifting joints, cracking, root intrusion, and cave-ins. The various types of problems with VCP are difficult to predict when they will occur, but it is predictable that it will eventually occur at some point, requiring a prioritized replacement program.
The AMT will continuously need to analyze, predict, and plan for replacement and upgrade projects in both the WT and WC systems. With all wastewater systems, O&M is extremely vital and critical at every level; therefore, recruiting, training and maintaining an expert Operations staff is the most important aspect of the wastewater systems.
Attachments
A - 2026 Wastewater Systems Annual Update