In Spring of 2013 I was part of a 30-person team working to create an action plan for Wellesley College to start composting, to comply with an upcoming Massachusetts organic waste ban. We began by approximating the amount of food waste that the college produces, investigating each dining hall’s contribution, and visiting other colleges that have implemented composting successfully.
We analyzed 12 different options for diverting Wellesley’s food waste from landfills. This included several options for composting on-campus such as vermicomposting and large rotary tumblers, several composting options off-campus including an anaerobic digester and a local windrowing facility, and other avenues including donating extra food to food insecure people or donating food scraps to a local pig farm. For each option, we did a cost analysis for the college, an environmental impact Life Cycle Assessment, and an assessment of social considerations such as risk, difficulty of implementation, and perception. We compared the analysis-results for the 12 different options along cost, environment, and social criteria to recommend our best set of options to the college.
Results of our social-factors analysis, in which each option gets points for improving the campus experience, improving educational opportunities, posing less risk to the college, having an easy permitting and regulation process, and being quickly implementable.
Results of our Life Cycle Assesment, created using SimaPro software, then aggregated to compare the full environmental impact across impact-categories including global warming potential, human health impacts, and ecotoxicity.
Results of our cost analysis, estimating the total cost to the college for each diversion method, per metric ton. This includes transportation and tipping fees for off-campus methods and includes capital costs, labor, energy, maintenance, and transportation costs for on-campus methods.
This plot most succinctly shows the final results of our comparison along three axes. Cost is on the y-axis so the least expensive methods are at the bottom. Environmental impact is on the x-axis so the best options are on the left, and social factors are shown with colors with the best options in green and the worst in red. We used this information to recommend Anaerobic digester 0ff-campus, windrows off-campus and tumblers (rotary in-vessel composting) off-campus.
You can read our comprehensive report and look at our final presentation hosted on the Mass.gov website using the links below.