HP Hood LLC, Lynnfield, Mass., is one of the largest dairy operators in the United States, with 13 plants across the country. It has been producing high-quality dairy products for more than 160 years.

Challenge

To keep pace with consumer demand, HP Hood has invested significant capital to increase production capacity at its Winchester, Va., plant. Evoqua Water Technologies, Pittsburgh, designed, built and commissioned the original wastewater treatment system for the plant, which included a low-rate anaerobic ADI-BVF reactor, sequencing batch reactor (SBR), spill tank and equalization tank.

Years later, when another planned production increase at the plant necessitated an expansion of the treatment system, Evoqua was selected to design/build a second BVF reactor and SBR to operate in parallel with the existing reactors.

But business showed no signs of slowing down for the dairy company. As HP Hood continued to grow, it carefully investigated wastewater treatment options for yet another expansion project at its Winchester plant.

Solution

The original wastewater treatment system at HP Hood performed so well — even while it was overloaded — that HP Hood once again chose Evoqua to accommodate its most recent increase in production. The upgraded wastewater treatment solution included:

• A new 3.44-million-gallon (13,020-cubic-meter) insulated concrete anaerobic BVF reactor.
• A 3,785-cubic-meters SBR (retrofitted from an existing 3,975-cubic-meter BVF reactor).
• An effluent equalization tank (retrofitted from an existing 190,000-gallon, 719-cubic-meter SBR).
• A waste sludge storage tank (retrofitted from an existing 230,000-gallon, 870-cubic-meter SBR).

The new BVF reactor works in parallel with the existing 1.23-million-gallon (4,656-cubic-meter) BVF reactor. The SBR aerobically polishes the BVF reactor’s effluent, and the effluent equalization tank attenuates effluent flow to the sewer. The waste sludge holding tank provides HP Hood with additional flexibility for handling and disposing of anaerobic and aerobic waste sludge.

The BVF reactor anaerobically removes over 90% of the influent chemical oxygen demand (COD) load, converting organics to a significant volume of biogas. The upgrade also includes a new biogas transmission and flaring system dedicated to the new BVF reactor.

Results

Evoqua and HP Hood continue to maintain their long-standing relationship, working together to achieve environmental sustainability through responsible wastewater treatment.

The upgraded wastewater treatment system is easy to operate and offers a high degree of process stability. The system provides a 46% increase over HP Hood’s previous average design flow, while still allowing the dairy company to meet the publicly owned treatment works’ discharge limits for biochemical oxygen demand of 800 pounds per day and total suspended solids of 550 pounds per day.