Collection Systems Design & Logistics Flashcards

What is 'commingled collection' in recycling?

Answer: Collecting multiple recyclable materials mixed together in a single container

Commingled collection (also called single-stream) allows residents to mix paper, plastic, metal, and glass in one bin, with sorting done at the MRF rather than at the curb.

What is 'diversion rate' and how is it typically calculated?

Answer: The percentage of total waste diverted from landfill; calculated as diverted tons divided by total waste generated

Diversion rate = (tons diverted from disposal) / (tons disposed + tons diverted) × 100%, measuring how much material is kept out of landfills and incinerators.

What does 'contamination rate' mean in a curbside recycling program and why does it matter?

Answer: The percentage of non-recyclable materials in the collected recycling stream, which reduces commodity value and can result in rejection

High contamination rates reduce the marketability of recyclables, increase MRF processing costs, and can cause entire loads to be rejected and landfilled.

What is 'source separation' in recycling collection?

Answer: Residents sorting recyclables by material type before collection

Source separation places sorting responsibility on the generator (resident or business), producing cleaner single-material streams that typically command higher commodity prices.

Which factor most affects the cost per ton for recycling collection?

Answer: Population density and distance between service stops

Denser service areas with stops close together significantly reduce the cost per stop and per ton because trucks spend less time driving between pickup points.

What is a 'buy-back center' in the recycling collection system?

Answer: A facility that pays residents cash for bringing in recyclable materials

Buy-back centers incentivize recycling by paying individuals directly for materials they bring in, which is particularly effective for beverage containers in bottle-bill states.