In-Vessel Composting System

To process all the organic materials collected through the Ecology Center's Community Compost Program, we operate an 'in-vessel' compost system in East River Park, just south of the Williamsburg Bridge. The 'in-vessel' system is coupled with a curing stage to turn kitchen parings into compost in about three month.

The first step of this process begins by layering nitrogen rich food waste with a carbon source in the form of high-grade sawdust, another "waste-product", collected from various local wood shops, into the ‘in-vessel’ composting system. The 'in-vessel' system consists of sixteen one cubic yard size plastic containers. Once a container is filled the lid is sealed, and the decomposition process begins. The containers are designed to facilitate an 'aerobic' decomposition process, by allowing air to pass through vents on the bottom and the top of the bins. During a retention time of 10 -15 days, the materials in the bins are reduced by one fifth of their original volume and reach temperatures of 150 degrees Fahrenheit, to ensure pathogen destruction.

The second step, or curing process, begins as we transfer the composted materials from the 'in-vessel' containers into ‘windrows’. The term 'windrow' is applied when organic matter is piled into long rows. In our windrows we hand over the job of ‘curing’ the composted materials to red wiggler worms, since the material is now cooling down and brimming with the many microorganisms worms find delicious. As the worms feast on this bounty, they digest the partially composted materials together with the microorganisms to produce worm castings, some of the most nutrient rich, energy packed food there is for plants.

The final step of the compost process is the screening of the materials, to create fine compost, without any rocks, sticks or other unprocessed material and of course to screen out the worms which are returned to feasting in the windrows.