Changes

[[Image:Co-composting.PNG‎|thumb|right|200px|[[Co-composting |Co-composting]], in Yemen (for credits, click the picture)]]

====Open co-composting====

There are two types of Co-Composting designs: open and in-vessel. In open composting, the mixed material (sludge and solid waste) is piled into long heaps called windrows and left to decompose. Windrow piles are turned periodically to provide oxygen and ensure that all parts of the pile are subjected to the same heat treatment. Windrow piles should be at least 1m high, and should be insulated with compost or soil to promote an even distribution of heat inside the pile. Depending on the climate and available space, the facility may be covered to prevent excess evaporation and protection from rain.