What mechanical treatment process is designed to cut large pieces of waste into smaller pieces?

The mechanical treatment process that is specifically designed to cut large pieces of waste into smaller pieces is known as comminution. Comminution involves the use of mechanical devices, such as grinders or shredders, to reduce the size of solid waste materials before they enter the more advanced stages of wastewater treatment. This step is essential because smaller particles can improve the efficiency of subsequent treatment steps, such as biological treatment, by increasing the surface area available for microbial action and reducing the potential for clogging and operational issues within the treatment system.

In contrast, grinding typically refers to the act of breaking down material into smaller pieces and is often a part of comminution, but it does not encapsulate the full scope of the comminution process. Screening, on the other hand, is used to separate larger solids from liquids but does not involve cutting; it primarily focuses on size separation. Filtration serves a different purpose altogether, aiming to remove particles from liquids by passing the liquid through a porous medium, rather than cutting waste into smaller sizes. This makes comminution the accurate choice as it directly addresses the need to reduce waste size mechanically.