How to Compost Sludge

Sludge is residue from waste-water treatment plants. It comprises mostly sand, dirt and microbes. In the raw state, sludge can threaten public health. After treatment with a method approved by the federal government, sludge is called "biosolids" and can be used for composting. Composted biosolids have been used in farming for 20 years but are not permitted for organic farming.

Instructions

• 1

  Remove moisture from the sludge in order to reduce its volume and to leave less moisture to evaporate during composting. This step is called "dewatering" and is usually achieved with lime or polymers.

• 2

  Reduce the odor of biosolids. According to Barbara Yeaman and John Walker of the Environmental Protection Agency (EPA), this is the most important step in composting sludge. They suggest a chemical scrubbing system as one approach to achieving this goal. However, sludge composting sites in relatively isolated settings require less odor control than sites in populated areas.

• 3

  Ship EPA-approved composted sewage sludge to outlets that provide compost for use in greenhouses, nurseries and landscaping.