This quip refers to the next phase of operational start-up requiring initial seeding of the anaerobic digester. The anaerobic digestion process harnesses natural bacteria to treat wastewater biosolids. At WSSC, these biosolids will first flow through the new thermal hydrolysis process (THP) followed by the anaerobic digesters (ADs). When initially commissioned, anaerobic digestion facilities require seeding with biologically active sludge to produce the population of methanogenic and acid-forming bacteria required for the anaerobic digestion process to work effectively. To accelerate the process of acclimation of the bacteria to the new environment, the preference is to seed with biologically active sludge that has gone through similar processes, in this case THP.

DC Water, located less than 15 miles from the WSSC Piscataway WRRF, also incorporated THP and anaerobic digestion at their Blue Plains AWWTP facility with the Main Process Train project, which was completed by PC in 2015. As a fully established facility, DC Water was happy to provide “bugs” that are “trained” to jump start the anaerobic digestion process. Beginning last night, tanker trucks containing this biologically active sludge began rolling into WSSC’s bioenergy facility and this sharing of special resources will continue over the next five days. Click here to watch last night’s excitement.

Once the seeding process is complete, initiation of full-time operation of the THP processes will begin. In preparation for this, the WSSC operations team has concurrently begun pre-dewatering activities, processing the indigenous biosolids produced by the Piscataway WRRF and storing the dewatered cake in the new cake storage silos. The volume of biosolids processed will ramp up from 4 dry tons per day to 16 dry tons per day over a 30-day period. Once this is complete, the facility will operate for another 60 days solely processing Piscataway WRRF biosolids before bringing biosolids from WSSC’s four other facilities to the site for processing through the new systems.

The Piscataway WRRF Bioenergy Project utilizes cutting-edge green technology to transform the way WSSC handles biosolids from all six of their water resource recovery facilities, significantly reducing the volume and creating Class A biosolids. The process will also reduce operating costs by more than $3 million per year and reduce greenhouse gas emissions by 15% by capturing and cleaning the digester gas to help power the facility through the CHP facility.

The post Major Operational Milestone for WSSC’s Piscataway WRRF Bioenergy Project appeared first on PC Construction.

The excitement on site was visible when the first truck delivering the Cambi unit arrived at the Piscataway site. Over the course of three days, nine trucks arrived delivering the modular Cambi components for installation by the PC team.

This was not PC’s first Cambi installation. The onsite team had the experience and lessons learned from installing the largest Cambi system in the world at DC Water’s Blue Plains AWWTP. The benefits of the planning process was evident as the trucks arrived in a set sequence and the modular equipment was offloaded directly to the awaiting concrete pad. Always with an eye on safety, PC’s team first erected the four smaller reactor tanks, followed by the feed pump skid, the flash tank and pulper tank and finally the walkway platforms and piping connecting the system.

This fall, a secondary pulper and feed tank will be delivered and installed. These components will ensure continuous operation during maintenance and inspection periods and will be the first Cambi system in the world with this additional operational capacity.

While the delivery and installation of Cambi was a key milestone, several other components have continued to progress. Dutchland has made significant progress on the deammonification tanks. After pouring the three base slabs, each sitting on a different elevation, they began erecting the 89 wall panels that form the tank as well as the 30 additional beam, walkway, roof and floor panels. With everything erected, large steel tendons were pulled through the panels and tensioned to achieve structural integrity and watertightness. The tanks are now ready for testing.

The PC team has also completed the cake storage pad facility, which will house the final Class A biosolids before it is hauled offsite. Work continues on the foundation for the cake receiving facility where trucks from other WSSC sites will deliver sludge to be processed through the THP facility.

DN Tanks is nearing completion on the two 1.5-million-gallon digester tanks. Foundations for the CHP, gas cleaning and storage facilities are being prepped and poured in anticipation of the equipment delivery.

Looking forward, Nitterhouse will soon be back on site erecting the precast concrete wall and roof system for the Solids building.

Stay tuned for updates as the Piscataway landscape continues to change!

Check out the progress:

The post The Cambi THP System Arrives at WSSC Piscataway Bio-Energy Project appeared first on PC Construction.

Some of Alan’s previous work with design-build projects includes the Main Process Train and Wet Weather Facility projects at the Blue Plains AWWTP project in DC, the Ralph Brennan WTP Gravity Filters Upgrades in Florida, the Hopewell Regional WWTF Phase 2 project in Virginia, and currently, the WSSC Piscataway Bio-Energy Project in Maryland.

Alan joins a growing industry of design-build professionals who are redefining project delivery throughout the United States. His commitment to the progress of the design-build methodology will help guide PC’s efforts as a leader in design-build construction.

The post Alan Parent Earns National Design-Build Certification appeared first on PC Construction.

PC’s self-perform team has set the seven belt filter presses at what will be the solids building housing all the pre- and post-dewatering activity for the facility. These are just a few of the large pieces of equipment being set into place prior to erecting the pre-cast concrete panels that will form this more than 16,000-square-foot building.

Nitterhouse Concrete has started to place the precast panels on several buildings including the chemical storage building, sidestream pump station and gas storage blower building. They will also begin erecting the solids building once PC completes the equipment installation.

Work continues on the two 1.5-million-gallon anaerobic digesters, including the massive cast-in-place concrete domes. Work is being completed on the structural integrity of the tanks and making them watertight through the process of wrapping and shotcreting the tanks.

The sidestream treatment tanks are starting to take shape as well. Dutchland’s team is onsite placing the foundations for the pre-cast post-tensioned tanks that will be erected in June.

Additionally, the cake receiving vault has been completed in preparation for the cake hoppers and cake storage bins. Foundations are being prepped for the generators, boilers and gas storage facility.

While so much has happened in the past month, the flurry of activity won’t end anytime soon. Stay tuned for more updates coming soon!

The post Big Changes at WSSC Piscataway Bio-Energy Project appeared first on PC Construction.

PC has partnered with DN Tanks to complete these circular prestressed concrete tanks. Each tank consists of 17 individual panels that are 50 feet tall and vary in width to create an approximately 78-foot-diameter tank. The largest panel weighed in at more than 30 tons.

The panels were cast on site in eight casting beds, four near each tank location. Once the casting was complete, each bed contained four or five stacked panels. Using a 500-ton crane, the panels were lifted from their beds and flown into place. Each tank took only two days to complete.

Now that the panels are in place, work can begin on the installation of the shoring and formwork to cast the digester domes. The tank joints still need to be infilled and the tanks wrapped with prestressing wire and coated with shotcrete. The tanks are expected to be fully constructed in Spring 2021.

The $271 million bio-energy project will use thermal hydrolysis process (THP) and anaerobic digestion to treat the biosolids and a sidestream process to treat the resulting effluent. The project is also designed to capture and clean the digester gas to feed back to the Washington Gas pipeline and/or to be used in the new CHP facility to generate electricity and steam to feed the THP process. The entire project is expected to be complete by the fall of 2024.

The post Stonehenge Recreated at WSSC’s Piscataway WRRF appeared first on PC Construction.

WSSC gave PC Construction the Notice to Proceed on Phase 2 construction in June. Since then, early subcontractors have mobilized and work is underway with a focus on the early foundation work over the summer. To date, this work includes:

• More than 100 auger cast piles have been installed to support the two new 1.5 million-gallon anaerobic digesters and digester control building.
• Additional erosion controls have been put in place.
• Base slab concrete for the filtrate pump station and the sidestream chemical storage building are underway.
• Construction has begun on a warehouse for materials storage.
• Subgrade preparation for the cake storage facility was completed.
• Support of excavation installation has commenced for the construction of the cake receiving vault.

The site is now bustling with activity as we move forward with this exciting project. Stay tuned for more updates!

The post Focus Shifts from Site Preparation to Construction at the WSSC Bio-Energy Project appeared first on PC Construction.

In April, the WSSC Water Commissioners approved Phase 2 funding, allowing PC to begin construction of the design-build Piscataway WRRF Bio-Energy Project in Accokeek, Maryland. The $228 million for Phase 2 brings the total investment in the green-energy project to $270 million and marks the final funding needed to construct WSSC Water’s largest and most technologically advanced project. At the heart of the project is how WSSC Water handles biosolids produced by the wastewater treatment process.

This new bio-energy facility will use thermal hydrolysis process (THP) and anaerobic digestion to treat the biosolids and a sidestream process to treat the nutrient rich effluent from the dewatering process. The project is also designed to capture and clean the digester gas to feed back to the Washington Gas pipeline and/or to be used in the new CHP facility to generate electricity and steam to feed the THP process. Surplus electricity generated can also be fed back to the electrical grid.

The facility has been designed to meet WSSC Water’s anticipated 2040 capacity with the THP’s capacity of 88 dry tons per day. The two digesters have a combined volume/capacity of more than 3 million gallons.

In addition to the major process facilities, the project also includes gravity thickening, a cake receiving facility that will accept solids from WSSC Water’s other WRRF’s, pre- and post-dewatering facilities, digested sludge storage, odor control facilities, a post-dewatering cake storage facility, and a gas storage and cleaning facilities.

Using cutting-edge “green” technology, the new facility will significantly reduce the amount of biosolids resulting from the treatment process, thus reducing costs to haul and dispose of the product. The remaining biosolids will be significantly cleaner (Class A), making the disposal process much easier and allowing the final product to be suitable for sale and distribution as fertilizer. This new process will reduce operating costs and is anticipated to save WSSC Water customers more than $3 million per year. Additionally, by recovering the digester gas and using it to help run the facility, WSSC Water will reduce their greenhouse gas emissions by 15 percent.

PC is underway with Phase 2 work as we continue toward completion of Phase 1 early work activities, referred to as the enabling work package, which includes demolition of existing facilities, hazardous materials abatement, site preparation and site utilities enhancements. This Phase 1 work is about 75% complete with most major demolition nearing completion. All work associated with the Phase 1 site preparation is scheduled to be complete in late August 2020.

To complete this project, PC is teaming with leaders in these specialized facilities – Stantec and Hazen and Sawyer. This winning combination brings together PC’s construction experience – including the largest THP facility in the world – with Stantec’s history of designing nearly half of the world’s THP facilities and Hazen and Sawyer’s biosolids and sidestream treatment expertise.

We are excited to collaborate with WSSC to move this environmentally significant project to successful completion. Stay tuned for more updates as this project progresses.

Photos: A look at the Piscataway WRRF site prior to construction (top) and currently (bottom).

The post Phase 2 Begins for WSSC’s Innovative Bio-Energy Project appeared first on PC Construction.

PC received the Notice to Proceed for the WSSC Bio-Energy Project Early Work Package earlier this fall. As part of this work, the team is in the process of removing hazardous materials from several buildings, installing erosion control measures, cleaning digesters and underground piping, clearing the adjacent ballfield that will house the trailer complex and beginning work on a temporary access road to the trailer complex.

December will bring demolition of the incinerator building to make room for the new bio-energy facility, demolition of ductbanks around the site and the installation of the construction trailer complex.

Work will continue through July 2020 with additional demolition, plant drain improvements and utility relocation. All this work is setting the stage for construction of the bio-energy facility, which is anticipated to begin in Spring 2020.

Click here for more information about this project.

The post Work Underway for WSSC’s Bio-Energy Project appeared first on PC Construction.

Starting-up equipment and moving millions of gallons of water at 3 a.m. has become the norm on the Tunnel Dewatering Pump Station and Enhanced Clarification Facility (TDPS/ECF) project as the team has worked toward, and now successfully completed, the system operational demonstration. This was the final full-system acceptance test before the tunnel bulkheads are removed from the influent tunnels, allowing combined sewer overflows (CSOs) during storms to be sent to the facility.

The facility is designed to treat 225 million gallons of incoming CSO from tunnels underneath Washington, D.C. Water enters through a 23-foot diameter tunnel and is stored in a shaft before being pumped by 83-mgd pumps to the ECF.

For the operational demonstration, influent was pumped from the existing plant to the ECF for treatment. The fine screens removed all solids larger than 6 millimeters from the influent and sent the material to storage containers for removal. The influent was then injected with ferric chloride and caustic soda to aid in settling and neutralize the pH before entering the grit vortexes. The influent then entered the three ACTIFLO High Rate Clarification trains, which are the largest in the world, and include coagulation, flocculation and settling tanks. The removal rates that were achieved far exceed the contract required performance guarantee.

Now that this test is complete, contractors upstream of the system can remove their bulkheads that are currently blocking flow from entering the facility. While that is taking place, our team will continue to make minor adjustments to the system, pump at limited capacity to keep the tunnel dry, and prepare for our next phase of testing scheduled to begin in early March. This next phase of testing will prove the facilities’ ability to handle the large combined sewer overflows the plant was designed to treat.

The post Project Update: Blue Plains AWWTP TDPS/ECF Passes Operational Demonstration appeared first on PC Construction.

When the University of New Hampshire was ready to move forward with the construction of their state-of-the-art NCAA Division I stadium, they turned to design-build delivery to ensure all their project goals were met. Teaming with PC Construction, Lavallee Brensinger Architects and Populous, design commenced immediately with construction following in May 2015. An aggressive schedule was adopted to meet the university’s required late summer 2016 completion date to accommodate the football season’s opening game. The design-build delivery method, combined with the release of early work packages and innovative problem-solving, allowed the team to deliver on time.

There are so many reasons why this project was a success. Certainly, having the right team involved from the start was a critical factor. The team embraced a highly collaborative environment, working together to achieve UNH’s vision. In addition, having early involvement by PC Construction enhanced the design and constructability review process and allowed the team to discover conflicts between proposed design and actual constructible conditions. Time and money was saved through this collaboration and cemented the team’s synergy throughout the project.

And, of course, the top-notch design epitomized the grandeur UNH sought out to achieve for their Wildcat Athletics program. Take in one game at Wildcat Stadium and you’ll know exactly what we mean.

So, thank you to everyone who contributed to this incredible project. We are truly honored to have been your partner.

The post Wildcat Stadium Receives DBIA Recognition appeared first on PC Construction.

Learn more about the project and read the entire POB article here.

The post Fitting a Square Building in a Round Hole appeared first on PC Construction.

DC Water’s Bailey Bioenergy Facility was recognized by the US Water Alliance with the prestigious 2016 U.S. Water Prize. The awards, which recognize organizations that are leading the way with creative water solutions, will be presented at the One Water Summit in Atlanta, GA, on Wednesday, June 8, 2016.

The Bailey Bioenergy Facility, constructed by the joint venture team of PC Construction and CDM Smith, produces a net 10 megawatts of electricity from wastewater treatment and an exceptional Class A biosolid by leveraging the relatively new thermal hydrolysis process. DC Water’s Blue Plains Advanced Wastewater Treatment Plant is the largest thermal hydrolysis plant in the world and the first in North America.

The resulting clean and renewable energy offsets the energy needs of Blue Plains by approximately one-third, reducing the plant’s carbon footprint and lessening dependence on the grid.

DC Water CEO and General Manager George S. Hawkins said, “The project is a crowning achievement for DC Water and exemplifies a shift from treating used water as waste to leveraging it as a resource. This innovative facility is generating renewable power, producing exceptional quality biosolids, reducing our carbon footprint, increasing plant efficiency, and ultimately saving ratepayer dollars.”

This design-build project included a dewatering building, 32 thermal hydrolysis vessels, four 80-foot tall concrete digesters and three turbines the size of jet engines.

The post DC Water Project Wins U.S. Water Prize for Turning Wastewater into Electricity appeared first on PC Construction.