Office of Environment & Sustainability

What are Johnson-Su Bioreactor Composters?

Formally known as a "Johnson-Su Bioreactor" (created by Johnson and Su), these composters are an effective, low-cost, and low-maintenance means to composting. Unlike traditional composting, which requires frequent turning to allow for oxygen to enter, a bioreactor is a no-turn composting system. The donut shape allows oxygen to enter from all sides, meaning it can passively aerate with no additional effort. After your bioreactor is full, it "cooks" for 9-12 months before turning into a ready-to-use soil amendment! A bioreactor composter is a perfect solution for those wanting to compost without needing to turn a compost pile.