The study looked at how well different sizes of filter media can clean dirty water. They tested small, medium, and large grains in filter columns. Smaller grains caused more blockages in clean water, while larger grains expanded more during backwashing. The smallest grains were best at removing dirt from very dirty water, up to 51%. Medium grains were effective at cleaning less dirty water, up to 50%. This shows that medium-sized filter media are good at removing dirt from water, helping to improve low-cost water filtration systems.