Testing the Waters: Establishing Trust in Remote Main Line Valve Automation

Date: Wednesday, September 16

Time: 9:30 – 10:00AM

Speakers: Chip Votava and Kayla McCoy

Description: HRSD operates an extensive wastewater interceptor force main network to convey flow to its treatment plants. To enhance operational flexibility and system resilience during wet weather events, HRSD is implementing automatically controlled system valves with a goal of greater system pressure control. At two separate locations, HRSD has installed 24/36-inch plug valves within underground vaults supported by control cabinets equipped with SCADA, programmable logic controllers, and local operator interfaces to dynamically divert flows between two different sewer interceptor force main routes based on existing system pressures. The system pressures are representative of available system capacity. This system utilizes real-time pressure data to automatically open and close valves to direct flow. As the first of its kind to be deployed in HRSD’s system to automatically control system valves, the project was approached with a high level of caution. Inadvertent failure of valves in a closed position could result in serious consequences. Therefore, the team approached the system activation with careful attention to evaluating failure of any potential component of the valves system with an eye toward eliminating the potential negative impacts. To ensure reliable performance, HRSD developed a comprehensive multi-day testing protocol involving staff at multiple locations within HRSD’s system. Testing includes monitoring valve positions, logging operational outcomes, and validating alarm functions under various conditions. Detailed field guides and functional descriptions are in the process of being updated to better prepare staff as they take on this new type of facility and to promote system integrity during future wet weather events. This presentation will provide an overview of the interceptor system, the automatic valve controls concept, the detailed testing approach, and results of the system performance. Construction is complete and final testing is in progress.

Over?! Under?! Through?! Potential applications for short length Horizontal Directional Drills on traditionally open-cut utility replacement projects

Speaker: Kyle Nguyen

Date: Tuesday, September 15

Time: 2:00 – 2:30PM

Description: Horizontal Direction Drills (HDD) are frequently limited to installations through environmentally sensitive areas, or larger and longer pipeline installations with significant staging area and stringout areas. For more common shorter length, smaller diameter water main and force main installations, HDD installation is not often considered over open cut installations. However, with recent significant construction price escalation, open trench installations are stressing utility replacement budgets, especially with respect to restoration costs. With appropriate design considerations, shorter length HDDs can offer a great balance of construction cost savings and acceptable operation and maintenance needs. This presentation will step through design, construction, and maintenance considerations for multiple HDD projects throughout Hampton Roads. The projects are a mix of water main and sewer force main replacements in various settings: neighborhood, industrial, and commercial. One of the keynote projects was designed and bid to be installed via open-cut installation but was later constructed via mini-HDD to reduce: project pavement restoration costs, avoid difficult utility crossings, accelerate the project schedule, and simplify Maintenance of Traffic (MOT) requirements. The project was completed on schedule and resulted in overall cost savings of ~$360,000 (~14% reduction). These projects have bolstered the City of Virginia Beach’s confidence in allowing and pursuing trenchless installation methods on future projects. It has also opened the door for use of HDPE pipe in their water and sanitary systems. As design engineers and contractors gain more experience implementing mini-HDD installation methods, traditional open-cut installation on large scale utility replacement projects will likely become less prevalent.