April 15, 2010
Cornell replaces incinerator with fully tested digester for disposal of animal remains
Cornell's incinerator at the College of Veterinary Medicine, which was officially shut down April 7, has been replaced with a new digester for disposing of animal remains.
The new system is part of a Waste Management Facility project that also includes removing the incinerator and installing a steam sterilization and shredding system for disposing of the university's medical waste, which will be completed this summer.
The switch is the result of years of planning by the Cornell Community Waste Management Advisory Committee (CCWMAC), which included Cornell faculty and staff, local government officials, and representatives from environmental groups and the Forest Home Improvement Association, many of whom took part in an informal ceremony to shut down the incinerator.
"I was very gratified with the process [of replacing the incinerator] as well as the outcome and the dedication of both Cornell and community people involved with the Cornell Waste Management Advisory Committee," said Brian Eden, a retired Cornell Law School Library collections manager, local environmentalist and committee member.
The project features several environmental benefits, including a more than 75 percent reduction in energy use compared with the incinerator. Water and heat captured from cooling the digester's effluent are reused in the treatment process. In addition, large translucent wall panels replace the need for electric lighting during daylight hours, said Paul Jennette, the College of Veterinary Medicine's biosafety engineer.
After two years of meetings, CCWMAC made recommendations to Cornell in 1998 for more environmentally friendly alternatives than a new incinerator. Its community members have continued to meet with Cornell staff as the project moved through planning, analysis, design and construction.
The CCWMAC-recommended alkaline hydrolysis digester -- which has been tested for months -- uses a state-of-the-art, water-based process that combines high pH, heat and pressure to treat animal remains, leaving an environmentally safe liquid effluent and treated solid remains.
"[The digester] has a lower environmental impact than the incinerator," said Jennette, adding that it reduces emissions, is safer for employees and less susceptible to interruptions from power failures.
It has "a substantial net gain over the previous process, including better air quality in the vicinity of the college and the Forest Home neighborhood, so we're happy with that," said Eden.
Cornell currently hauls the digester's effluent to Watertown for methane conversion. The Ithaca Area Wastewater Treatment Facility is completing a permit analysis before it will accept the digester's liquid effluent. At the treatment plant, the liquid waste will be converted to methane for energy use by the plant itself.
While testing the digester Feb. 19, 4,300 gallons of fully treated effluent was accidentally discharged into the Ithaca sanitary sewer system. The issue was immediately addressed by Cornell operators and has since been fully resolved, with additional safety measures added to prevent accidental discharges. "The effluent had already been demonstrated to be completely treatable by the Ithaca Wastewater Treatment Plant," said Jennette.
Historically, the incinerator was used for animal remains, while the university employed an outside disposal company for medical waste (which is sealed in red plastic bags or sharps containers, like those found in doctors' offices). Once the project is completed this summer, the sterilized and shredded medical waste will be placed in an enclosed dumpster along with the digester's solid remains; the dumpster's contents will be hauled to a permanent sanitary landfill in Ontario County.
"We're making the waste safe for transportation and disposal instead of relying on someone else to do that function elsewhere," said Jennette.