As part of ILSR’s Baltimore Composting for Community Project, we are supporting about a dozen community compost sites in the city. This month we hosted two events in Baltimore to build DIY compost screeners designed for the community scale. In collaboration with the Baltimore Office of Sustainability and its Food Matters Project, ILSR partnered with ECO City Farms and ECO’s compost guru, Benny Erez, to adapt and build his two rotating screener (aka trommel screener) designs. One design is people-powered with a simple hand crank. The other has a motor. Both designs rely on repurposed bicycle wheel rims.
At Hidden Harvest Community Farm, we built the hand crank version for its compost cooperative. At Malcolm House (formerly Jonah House) we built two of the motor-powered design: one for Malcolm House and the other for the Baltimore Compost Collective.
This webpage will be updated when the community trommel screeners are completed and we have pictures of them operating. Still to come is attaching the hand crank and the motors as well as testing the devices! If you are interested in learning more about these designs, please email us at firstname.lastname@example.org.
Why Screen? and Sample Community Composter Screeners
Screening or sifting compost is often worth the effort. It will remove contaminants and pieces of material not fully decomposed (such as wood chips, fruit pits, corn cobs, and pineapple tops). Indeed it is a common step in the community composting process.
There is no one way to screen compost. A common method for home composters is a simple DIY wooden frame around ¼-inch hardware cloth sized to fit over a wheelbarrow. Large-scale industrial sites typically use large rotating “trommel” screeners, which essentially are huge rotating cylinders costing tens of thousands of dollars. Vibrating shaker screeners are also utilized.
Community-scaled sites have several options, most of which fall into the DIY category. (There generally remains a lack of composting equipment scaled for small-scale sites. Screeners are no exception.) These options include:
- Wheelbarrow screener
- Table screener
- Screener over bin
- Standing/folding screener
- Rotating or trommel screener (hand crank and electric powered)