The Four Main Methods of Processing Biosolids
- DIGESTION: Anaerobic digestion is the breakdown of organic, biodegradable material in the absence of oxygen. The resulting end products are an energy-rich biogas which consists of methane, carbon dioxide and water vapor, and nutrient-rich digested solids known as biosolids.
- THERMAL DRYING: Thermal drying takes biosolids cake to a minimum total solids content of 90 percent, using various technologies. The resulting product is a dry Class A granule.
- SOLAR DRYING: Solar drying is a type of thermal drying that reduces the total solids content by using readily available, free energy: solar radiation. Solar drying depends on the sun and ambient air to dry the solids without the use of fossil fuels. It is a slow process, requiring a larger footprint than heated thermal drying.
- COMPOSTING: Composting is a high heat process (greater than 131ºF) that transforms biosolids into a stable, pathogen-free soil conditioner that releases nutrients slowly. Biosolid composts are considered Class A biosolids, and they can be used like any other compost product.
To learn more about our biosolid programs and how we help our community partners take full advantage of their benefits, contact Chris Gutschow.