- Elimination of extra steps and problems involved in the excavation of the disposals of screening (screened material)
- Often difficult to dispose highly polluted screenings - In USA if buried, 6 inches of cover material should be used
- Highly suitable for small treatment plants. e.g. : mountain or beach resorts.
- Frequent maintenance of cutting tools ( delicate equipment)
- Risk accumulation of comminuted materials (textiles, vegetable fibers) eventual clogging of pumps and piping.
- These materials to form floating scum in anaerobic digestion
- Problems in trickling filter (clogging of distribution pipe holes) mainly used in activated sludge process.