Hilltop’s food waste composting program started in September 2011 out of the efforts of Steve Akers, Associate Director of Residential Program Services (RPS) environmental operations, Brad Hayden, General Manager for RPS Dining Services and Lea Woodard, Coordinator Hilltop Garden & Nature Center, with the hope that at least some of the food waste from Indiana University dining halls could be diverted from a landfill and used to create nutrient rich compost for gardens on the IUB campus.

As the composting program grew over the following years, new and larger compost bins were built and the logistics of the composting process were refined. We are still learning how to make a more efficient system, but as of the spring of 2015, IU Building Services collected about 600 gallons or about 2700 lbs of food waste in 33 gallon cans each week from four different dining facilities during the IUB academic school year and delivered them to Hilltop Gardens to be composted.

Below is a timeline of our composting efforts:

Starting in the fall of 2011 about 50 gallons of food waste was collected from Union Street Market each week and delivered to the gates of Hilltop Gardens. A process was developed so that RPS environmental operations staff picked up the food waste in five gallon buckets from the Union Street Center and delivered them to Hilltop. At that time, Hilltop’s work- study students emptied the buckets in our compost bins, added wood chips or leaves and return the cleaned, empty buckets outside Hilltop’s gate to be picked up by the environmental operations staff.

In October 2012, we began collecting food waste from Read Dining Hall in the amount of about 75 gallons of food waste each week.

In the fall of 2013, the Indiana Memorial Union dining facilities came on board by providing about 100 gallons of food waste per week to our composting operation. Because of the much larger amount of food waste collected, 35 gallon cans were used instead of the 5 gallon buckets.  Sodexo is the food service company that manages the dining facilities within the IMU and has helped us create a complete food cycle within the IUB campus. At Hilltop Gardens, there is an 8500 ft.2 garden that is managed by IU students through the IU Office of Sustainability. Part of the food produced within this garden is picked up by Sodexo staff and served at dining facilities within the IMU. The food waste from this produce is then composted at Hilltop and put back into the garden to provide nutrients to grow additional produce. This is the food system we try to demonstrate and encourage at Hilltop Gardens.

In February of 2014, The Restaurants at Woodland dining hall began supplying about 200 gallons of food waste per week to the composting program.

As the amount of food waste changed over time, we adapted our composting system. We started out using the Earth Machine compost bin, but once we had multiple dining facilities providing food waste, we needed larger bins. In 2013 we started building 4 x 4’ x4’ compost bins out of wooden pallets collected from the IU campus.

Earth Machine compost bin

Series of indoor compost bins at Hilltop

Series of indoor compost bins at Hilltop

We built a series of 8 bins to contain the food waste layered with leaves and yard debris. Once a bin was filled, we turned the contents of the bin into the adjacent bin. After about 6 or 7 turns and 2-3 months later, the food and yard waste had turned into finished compost. The finished compost is then used in our gardens at Hilltop and potting soil mixes.

The wooden pallet bins were built inside our hoophouse (unheated greenhouse). This allows us to continue composting through the winter months because the hoophouse is warm enough during the day to keep the compost from freezing and continuing to decompose. The heat generated by the compost also helps keep the hoophouse warm in the winter time.

In the summer months, we use our outdoor compost bins that are much larger than the indoor bins. These bins are 8’ wide, 8’ deep and 5’ tall. The larger bins allow for a small tractor to turn the contents of the bin instead of us having to turn the bins by hand.

Outdoor compost bins at Hilltop Garden

In January of 2015, a series of new, ‘forced air’ compost bins were built and replaced the indoor, wooden pallet bins.

The new bins

The new bins are 5’ x 5’ x 5’ and have a perforated PVC pipe running underneath and through the

 middle of the compost bins.

The new bins have a blower controlled by a timer that turns the blower on every 2 hours and runs for about 7 minutes.

The forced air system takes the manual turning of the bins out of the composting operation. The turning of the bins helped incorporate the necessary oxygen into the compost, but now the blower pushes air throughout the compost on a regular basis, which helps speed up the composting process. The forced air also helps regulate the moisture in the bin. We do have to add water to the compost bin more often with this system.

As the amount of food waste collected at each dining facility increased, the size of the container that the food waste was collected in increased too. Below is a picture of the 33 gallon trash cans used to collect food waste in each of the dining facilities. Labels preventing non-compostable materials from entering the bins were placed on the lids.

Trash bin

As of the spring of 2015, Hilltop received about 600 gallons of food waste each week during the school year from the following IU dining facilities:

350 gallons from The Restaurants at Woodlands

150 gallons from The Indiana Memorial Union dining facilities

50 gallons from Union Street Market Place

50 gallons from Edmonson Dining Hall at Collins

More about IUB’s composting efforts can be found at Inside IUB’s newsletter article: http://inside.indiana.edu/features/stories/2015-04-30-composting.shtml