Friday, February 1, 2019

BLOG: Curbside Composting

by Catherine Chertudi, City of Boise, Idaho

Nearly 74,000 households now have the opportunity to divert compostable materials from the landfill to a Boise City owned composting facility!

The residential compost collection program was initiated nearly two years ago based upon recommendations from a citizen’s advisory committee to reduce wastes sent to the landfill. The idea took flight when the Ada County Landfill completed a year-long study of waste disposed in the landfill. The city discovered that nearly 46% of all residential wastes placed into the landfill were compostable materials.

Realizing that nearly half of our residential wastes could be diverted and used to make a valuable product created the momentum needed to begin discussions to develop a city-wide compost program.

Collecting compostable materials is easy – the issue was having a site to conduct the composting process. For many years, the city had hoped the private sector would develop a regional compost facility, however with the amount of dairy wastes in the area, a residential compost facility was not seen as a high investment priority. Ultimately, the city and our franchised hauler, Republic Services agreed to partner to design, build and operate a composting facility on city-owned property.

The ideal site was found on a portion of the city’s Twenty-Mile South Farm which is used to manage biosolids. The selected location is not ideal for farming – due to basalt outcrops and rocky ground. However, the site was perfect for composting. About 40 acres have been dedicated to the composting facility which includes a scale, office, receiving and windrow pads. The design incorporates extensive storm water and compost leachate management to protect groundwater. A monitoring plan was also required as part of the site permitting process with the Idaho Department of Environmental Quality and Central District Health Department.

The design and permitting process for the new compost site was nearly 9 months long and required three major revisions to the compost siting application with the Idaho DEQ. Construction of the facility started in April 2017 and will be completed in August. On June 5, 2017 we began delivery of nearly 74,000 wheeled carts to collect the compostable materials and the full cart roll-out was completed July 15th. The first phase of the compost pad opened June 22, 2017 and by July 17 we have already collected and are composting about 1400 tons of yard wastes and kitchen scraps.

The site was designed for about 95 tons per day and we expected to begin with 45 tons per day – we have already seen the results exceed our projections with nearly 66 tons per day collected in the first five weeks of the new program. And, we have reduced trash routes to the landfill by two trucks per day.

The compost process takes about 100 days and the city intends to give back to our customers first – providing free compost and using compost on city properties. Our high-desert soils will benefit from incorporating compost which improves soil and plant health and, most importantly, acts as a sponge to retain water which reduces the need for frequent irrigation during our hot summer months.

Boise residents are supportive and excited about the new composting program – and their commitment to protecting and conserving our great quality of life is evident in their participation in the new program and the low levels of contamination in the compost carts. Reducing wastes and conserving resources is one of our core values in creating a lasting environment for today and for future generations of citizens in our city.

To learn more, visit

No comments: