Designing a treatment process without knowing the influent parameters can be very difficult. Yet when it comes to grit removal system design, plant designers are often asked to do just that. WEF Manual of Practice guidelines for grit system design vary widely, which is understandable given the range of plant types and sizes in North America.

Influent grit characterization studies can be very helpful but they are often just a “snapshot in time” due to the limited number of tests. It is difficult and expensive to sample and characterize grit over the entire range of conditions a treatment plant experiences. Designers are often forced to select equipment based solely on feedback from plant staff and intuition. For designers looking for data on plant influent grit size distribution but do not have the capability to perform extensive grit characterization studies, Hydro International offers access to its Regional Grit Gradation database