Wastewater – DuBois & King, Inc.

Wastewater Treatment Upgrade

Comprehensive upgrade of 40-year-old wastewater treatment facility and process conversion from tricking filter to sequencing batch reactor (SBR) to comply with stringent phosphorous limitations. Replaced outdated headworks with fine screen and aerated grit chamber to improve removal of inorganics and FOG. Project included an innovative reuse of existing treatment process tank for post-SBR flow equalization, resulting in $200,000 savings.

Completed upgrade/replacement of biosolids processing including replacement of anaerobic digesters with aerated sludge storage, evaluation of alternative sludge dewatering technologies, new centrifuge and dewatered sludge screw conveyor, and efficient on-site storage/off-site hauling. Eliminated public health/safety threat by converting from 1-ton gas chlorine to liquid chlorination/dechlorination system. Energy efficient design techniques included premium efficient motors, heat recovery system from blower room, innovative day-lighting in Control Building, and new SCADA system for improved on-site/off-site monitoring. The site was constrained by the railroad and the Dog River, requiring geotechnical measures to protect rails.

DuBois & King was the prime consultant and provided all the professional engineering services associated with this facility, including structural, civil, electrical, mechanical, and construction inspection and management. The project received an award for engineering excellence in the annual competition sponsored by the American Council of Engineering Companies, Vermont Section.

WWTF Process Conversion, Upgrades, and Siphon Design

Process, civil, structural, mechanical and electrical design, permitting, and construction phase services for an $8.9 million comprehensive upgrade of the 40-year-old wastewater treatment facility that serves the Town of Randolph. D&K assembled a team of professionals including a local architect, geotechnical engineer, and energy management specialist. A new sequencing batch reactor (SBR) was designed to provide operational flexibility in the face of pending nutrient (including nitrogen) removal requirements in the Connecticut River drainage basin.

The project included new headworks, fine screen, grit removal, chlorine disinfection/dechlorination, aerated sludge storage, and centrifuge dewatering and a backup generator. Using a holistic and integrated design approach, opportunities were maximized to incorporate energy conservation and renewable energy features into the upgraded facility while minimizing ongoing operational and maintenance costs.

Included in the project is the Route 66 Siphon, which is a two-barrel siphon that conveys approximately 40% of the Town’s wastewater flow under Ayers Brook and to the wastewater treatment facility. The siphon is comprised of two (2) 8-inch HDPE siphon barrels, each approximately 1,800 feet in length, along with associated inlet and outlet structures, as well as cleanouts along the siphon. This siphon allows the Town to downsize the Route 66 Pump Station, as the siphon vastly reduces the flow handled by the Route 66 Pump Station.

USDA Forest Service Kiasutha Recreational Area

Inspection, evaluation, and design of improvements to the Kiasutha Recreational Area located in the Allegheny National Forest. Performed inspections of the project site to make improvements for new campsite locations, orientation, accessibility, slopes and grading, drainage, and utility connections. Services included:

Field Survey/Data Collection. Survey and inventory/base maps.

Roadway/Transportation. Design of cul-de-sacs, new parking areas, new roadway sections, replacement of culverts, new drainage ditches, and riprap ditch lining.

Campsite Improvements. Design for improvements and construction of new campsites.

New Campground Loop. Design for new campsite loop including 20 campsites.

Site Design. Design of amphitheater, two playground areas, and accessible pathways.

Facility Improvements. Water, electric, and sewer upgrade design including shower/restroom buildings, and picnic pavilions.

Water System Improvements. Design for new waterlines and replacement of existing waterlines including new valves, stops, and water system drains.

Sewer Systems. Design for new and rehabilitation of sewer lines and manholes, correct infiltration and inflow, and new hookups for campsites.

Electrical System Improvements. Upgrade and design of new electrical services and equipment, and increased capacity upgrades.

Sewer Line Extension

The Lower Plain region of Bradford, Vermont, is characterized by residential and commercial development and an underutilized industrial park. Lack of access to the Town’s wastewater treatment facility has been an impediment for further development in the Lower Plain region and specifically in the industrial park. The Town initiated a sewer system expansion project to serve the Lower Plain region and to help attract new business. DuBois & King provided the design for the sewer line extension and worked with the Town to secure project funding.

The project resulted in the extension of municipal wastewater service to the Lower Plains region of the Town, which is characterized by commercial and industrial development including the Bradford Industrial Park. Final design was completed and permits obtained for 10,000 ft of 8-inch diameter gravity sewer, 7,000 ft of 4-inch diameter force main including crossing the Waits River, and a wastewater pump station. Long sewer runs, very flat topography, and close proximity to State roads and associated right-of-way resulted in a complicated sewer alignment design. Numerous sewer mainline and service crossings of Routes 5 and 25 required a jacking/boring operation to minimize disturbance to these State roads. The design included an approximate 300-ft crossing of the Waits River using horizontal directional drilling for installation of the 4-inch diameter HDPE force main. Professional services included assisting the owner with landowner coordination.

Prince Street Siphon Design

DuBois & King provided design and construction phase services for an emergency replacement of a double-barrel sewer siphon in Randolph, Vermont. The original siphon was destroyed by Tropical Storm Irene when the Third Branch of the White River migrated 90 ft to the northeast. D&K engineers assisted the Town with damage assessments immediately following the storm, including identifying and coordinating the installation of an emergency bypass pumping system to eliminate the discharge of raw wastewater into the river from approximately two-thirds of the Town.

Fast-track design included topographic survey of the new river alignment; design of a 300-ft-long, double-barrel, 8-inch diameter HDPE siphon installed using horizontal directional drilling; new siphon inlet and outlet structures; replacement/rerouting of 250 ft of gravity sewer and manholes on the north bank; and preparation of easement drawings and coordination with the Town’s attorney. Assisted the Town with an abbreviated contractor procurement process that was acceptable to FEMA, and provided administrative assistance during construction, periodic inspection, and preparation of record drawings. The project received an Engineering Excellence Grand Award from the American Council of Engineering Companies Vermont Section.