Garelick Farms, a Dean Foods company, uses an anaerobic digestion process in their Waste Water Treatment Plant to pretreat the dairy wastes prior to discharge to the city sewer system. A byproduct of the process is large quantities of biogas (methane) which is normally burnt off at a flare.
With an eye towards both environmental concerns and operating energy costs, a biogas-fired Combined Heat and Power (CHP) system was proposed.
ENGVT was selected by EPS, an ESCO with a national energy management contract with Dean Foods, as the engineering firm for the project. Our scope included review of available technologies for the waste-to-energy plant, perform all engineering design, air permitting, and Mass DEP grant applications, and to provide construction assistance and start-up commissioning for the CHP system. ENGVT recommended Capstone Microturbines as the CHP technology. The turbines were fed by a high pressure gas compression and purification system to prepare the gas to “pipeline gas” specifications for combustion.
Each system produces 350kW of electrical and 1.5MMBTU of thermal energy which is used on-site for process heating and electrical loads.
The waste-energy-system in Lynn was installed in an area of the WWTP that housed an aeration system no longer in use. This area was gutted, structurally re-framed, and a new combustion air system installed.
The Franklin installation was installed on a new equipment pad on the exterior of the WWTP. A separate glycol hot water system was designed to distribute the CHP thermal energy to the plant.