Innovative $150 M Plant Expansion in Virginia Enhances Operations & Reduces Costs

HDR and the Hampton Roads Sanitation District (HRSD) produced this award-winning video* to commemorate its largest capital improvement project and to educate visitors about the mission and important role the Atlantic Treatment Plant (ATP) plays in the region.

Originally built in 1983 with a capacity to treat 36 million gallons of wastewater every day, the Atlantic Treatment Plant in Virginia Beach is the largest of HRSDs 13 plants. In 2010, a major expansion was completed with the addition of 18 MGD of capacity - enough to handle projected flows for the next 20 years. Through innovative design, the plant's overall ability to treat effluent was increased by 50 percent. Plant operations were also significantly improved, increasing efficiencies while reducing costs.

As one of the top wastewater design firms in the nation, HDR Engineering directed a team of nearly 200 engineers, designers, planners and CAD technicians to produce the plant's award-winning design.

"Every project is different and requires a custom approach," HDR Senior Project Manager Bill M'Coy, PE, said. "There's no cookie cutter to wastewater treatment plant design. There are some very specific characteristics to the Atlantic plant that we had to factor into our design. So we worked as a team with HRSD and the contractor throughout the process. The real reward is when the new facilities are put online."

HRSD was able to save $25 million in initial construction project costs at the Atlantic Treatment Plant through an innovative site preparation plan designed by HDR.

"We did have a number of challenges on this project," M'Coy said. "One was the soil, the poor soil conditions. So to meet those challenges we designed a surcharge system to pre-compress or pre-consolidate the soils. That involved moving approximately a 1 million cubic yards of soil and placing that on the location of the new structure."

As part of the preliminary design phase, HDR evaluated concepts that would provide lowest life-cycle costs and improved service. Increasing the efficiency of the solids handling system also was a priority. The ATP employed a labor-intensive dewatered cake handling system. Working with HRSD, HDR relocated the centrifuges to a new building adjacent to the cake storage pad. This eliminated the cake hauling operation, saving HRSD more than $350,000 in annual O&M costs. The new gravity belt thickeners were installed where the centrifuges were located, avoiding the need to construct a new thickening building.

HDR developed design plans to convert the existing digesters into a two-stage acid-phase digestion system. By employing this digestion process, the ATP increases volatile solids reduction by 10 percent, saving HRSD more than $150,000 annually in land application and dewatering chemical costs.

Continuing its commitment to a sustainable environment, construction of a new $8.1 million combined heat and power (CHP) system to capture and clean the digester biogas will be completed in 2012. HDR designed the system and helped secure funding to support its implementation. The estimated energy cost savings for the digester gas CHP system is $245,000 per year.

* Winner of a 2011 Bronze Telly Award for Video Production and Education Excellence