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Composting at HLS


What is Compost?

Compost is the product of a biological process during which naturally occurring aerobic (oxygen-requiring) microorganisms break down organic materials such as food waste into humus, a nutrient-rich material that can be used to improve soil quality.  During the composting process, the microbes use inputs of oxygen, moisture and organics to generate heat, water vapor, and carbon dioxide as they transform organics into humus.

Why Compost?

Emissions avoidance:

  • Organics degrading in landfills without air emit methane (a greenhouse gas 21 times more potent than CO2).
  • Composting adds oxygen to organic waste, so it emits only CO2 as part of the natural carbon cycle during decomposition.

Soil enrichment:

  • Provides nutrients for soil
  • Helps soil retain moisture
  • Reduces soil pollution
  • Reduces need for pesticides

Water management:  

  • Improves soil absorption, decreasing erosion
  • Improves soil filtration, decreasing polluted storm-water runoff

Economic benefit:

  • Reduces need for water, fertilizers, and pesticides
  • Extends landfill life
  • Provides a cost-effective alternative to conventional methods of cleaning contaminated soil

Composting at Harvard

Composting at Harvard Today:

• Harvard recovers nearly 4,000 tons of compostables annually, including food scraps and landscape waste.
• Food scraps from nearly all food preparation facilities at Harvard are composted.  Many University cafés also offer “front of the house” composting including the Hark here at the Law School, Chauhaus at the Graduate School of Design, Rockefeller Refectory at the Divinity School, the Greenhouse at the Science Center, the Barker Café, Sebastian’s at the School of Public Health and others.
• Compost is an essential component of Harvard’s Organic Landscaping efforts.  Over the past several years, the Landscape Services team in the Facilities Maintenance Operations group (FMO) has been transitioning its maintenance programs from conventional to fully organic methods. Each year at the Facilities Maintenance Operations Compost Facility in the Arnold Arboretum, Landscape Services converts more than 500 tons of leaves, grass clippings, tree branches, and other landscape waste and reintroduces it to the Harvard landscape in the form of compost, mulch and “compost teas” that suppress disease and deter pests.  To learn more about our organic landscaping practices, visit

The Opportunity:

  • Harvard Wide: Waste audits have determined that Harvard-wide, compostable food scraps and soiled paper represents 25% of our total waste.
  • AT HLS: In dorm waste audits, HLS Green Living Representatives have found that 41% of waste found in the trash could have been composted. Over the course of the year, composting all organics in dorms could save 7.1 MTCDE, or the equivalent of removing 1.2 cars from the road.

Composting at HLS

Harvard Law School was the first of all the School’s at Harvard to implement campus-wide composting.

Composting occurs in 3 ways at HLS:

  • At the Hark: Restaurant Associates, the Law School’s food service provider, has partnered with Republic Services to compost all food waste and most service-ware from food service activities.  This helps us divert over 50 tons of material each year.  All food scraps from food preparation are composted back-of-house, and bins are available for front-of-house composting in the Harkness café, HarkBox and Hark patio during the outdoor dining season. To help you properly sort leftovers, there are signs posted above bins showing you which materials go where.  It is very important that only compostable materials go into compost bins—other items, particularly plastic and metal, are harmful for the farms which use our finished compost!  In the Hark, you may leave leftover food, napkins, tea bags,  wooden coffee stirrers, and other compostable products on your plate when you bus your tray to the Hark dish drop, and RA staff will take care of the rest.
  • Event composting: Composting is available for set-up at all events. If you are booking a space through the Events Scheduling and Support Office, please indicate that you are interested in learning more about event composting when you fill out your full-service form.  Contact the HLS Sustainability Manager to discuss your event composting options and any questions you may have.
  • Building composting: Compost bins are located in every dorm and academic and administrative building.

What can I compost?

What CAN be composted?

• ALL food waste (including grains, breads, meat, bones, dairy, fruit peels and seeds, vegetables, tea bags and coffee grounds, paper filters)
• napkins
• paper towels
• compostable coffee cup sleeves from the Hark
• compostable Greenware cups from the Hark
• Compostable soup cups from the Hark
• compostable take-out containers from the Hark
• wood coffee stirrers and chopsticks
Soiled paper take-out food boxes
• Plants and leaves including houseplants and soil, yard waste and flowers

What CANNOT be composted?

• Coffee cups and lids
• Soup lids from the Hark
• sugar packets (these are lined with plastic coating that does not biodegrade)
• plastic ketchup or similar single-serve dressing and sauce packets
• styrofoam
• paper coffee cups not from the Hark (most coffee cups are lined with plastic)
• paper plates (most paper plates are lined with plastic)
• food wrappings (chips, cookies, etc.)
• plastic and metal
• used tissues


Compostable Products

What are “Compostable Products”?

The Hark offers biodegradable disposable service-ware that can be composted.  These products (including cups, bowls and take-out clamshells) are made from renewable resources and will bio-degrade in the commercial composting environments. The products are not derived from petroleum but from plant materials including vegetable oils and starches and molded fibers such as bagasse (sugarcane) and grasses, etc. The lifecycle costs and emissions generated by the compostable products we use at the Hark are less than or equal to those of traditional recyclable disposable products.

In order for a product to be considered compostable, it must:

  1. Biodegrade – the material’s carbon chains break down by naturally occurring microorganisms (bacteria, fungi, etc) into energy (heat), carbon dioxide, water, and biomass at the same rate as cellulose (paper).
  2. Disintegrate – be indistinguishable in the compost, that is, not visible or able to be screened out.
  3. Not be eco-toxic– not produce any toxic materials; resulting compost can support plant growth.

How can I tell if a service item is compostable?

See list below of compostable Harkness serviceware. Harvard uses BPI certification from the Biodegradeable Products Institute as our accepted standard for what is compostable, so look for the BPI logo (below) and/or check labeling – plastic made from bio-degradable plastic usually say “PLA” (which stands for poly-lactic acid), and/or “COMPOSTABLE” on the bottom.  If you bring in a cup, plate, etc. from an outside vendor, it most likely is NOT bio-degradable and should be placed in the WASTE bin (even paper coffee cups and paper plates usually have a plastic lining, and are not compostable). Not sure if something is compostable? Contact the HLS Sustainability Coordinator at or 617-384-6893.

TIP: Always purchase compostable plates and utensils certified by the Biodegradeable Products Institute (

Compostable Serviceware Offerings at the Hark:

  • Greenware cups (
    • Made from PLA (polylactic acid or Polylactide), a corn derivative.
    • Products use a PLA made by NatureWorks, which is currently made from No. 2 yellow dent field corn grown within a 300-mile radius of their Nebraska facility.
  • Ecotainer products (hot cup sleeves, soup bowls and lids):
    • Products are paper fibers coated with PLA (also NatureWorks brand).
    • Paper fibers made from trees certified to adhere to the Sustainable Forestry Initiative® (SFI®) guidelines for management and harvesting.  No trees from old-growth or endangered forests are used.  More than two-thirds of the energy used to make the paperboard comes from renewable resources.
  • Earthsmart products (take-out containers and plates/bowls):
    • Made of bagasse, a sugar cane derivative.
    • Production of bagasse products use ¼ of the water and energy and creates ½ the emissions used to produce comparable paper products.

***Note—compostable containers are not intended to be used in the microwave, and do not hold up as well when heated.***

I am concerned about using a food source, such as corn, as packaging when there are so many global food shortages.

This is an incredibly complicated issue, and we don’t have an easy answer, but agree that this is a serious problem and should be addressed at all levels. For now we feel the positive waste reduction and greenhouse gas emissions reduction benefits outweigh the negatives from use of these biodegradable products, but will continue to learn about this issue and will consider all impacts of our choices for future decisions.

Additional Resources

How can I set up composting at home?

If you have space outside to keep a bin, check with your municipality to purchase a bin and for guidelines.  If you don’t have space outside, you can still compost inside, with vermicomposting (worms).  See resources for composting options around HLS below.

  • Cambridge: The Cambridge Department of Public Works website provides information about composting options, from vermicomposting to purchasing a backyard bin ($50) to food scraps drop off locations. Cambridge residents may bring bring food scraps (in a paper bag or reusable pail) to the Recycling Drop Off Center at 147 Hampshire Street Tues/Thurs 4-7:30pm & Sat 9-4pm.  Food scraps may also be brought to Whole Foods (115 Prospect St) every day from 8am-10pm, to toters located in the rear of the parking lot on the left side.
  • Somerville: Purchase an outdoor compost bin ($40) from the Department of Public Works.
  • Boston: Purchase an outdoor compost bin from the City of Boston ($50) from the Boston Building Materials Co-op, 100 Terrace Street, Mission Hill, 617-442-2262. To learn more, visit
  • Elsewhere in MA: Check out your town’s recycling or public works page for more information, and visit

Other resources

1. United States Composting Council:
2. EPA:
3. Boston Globe Magazine article: Municipal Composting in Boston?: