What is the term used for sludge that has only been partially digested in the wastewater industry?

The term used for sludge that has only been partially digested in the wastewater industry is known as "green" sludge. This type of sludge contains a mixture of organic materials and microorganisms that have not yet been fully decomposed through the anaerobic digestion process.

Understanding the characteristics of green sludge is important for wastewater treatment operations. Since it has not undergone complete digestion, green sludge often has a higher organic content and can contribute to further treatment challenges. It may require additional processing or stabilization to facilitate its breakdown and to ensure that the end product meets regulatory requirements or is suitable for disposal or land application.

The distinction between the different types of sludge, including green sludge, is critical for operators as it influences the operational decisions, such as the need for additional treatment or the choice of methods for handling and processing this byproduct from the wastewater treatment process.