Abstract: A filtration apparatus having a plurality of sample wells comprises an upper plate comprising a plurality of upper wells, a lower plate comprising a plurality of lower wells disposed in flexible communication with each other, and a ratcheting mechanism disposed at interfaces of the upper wells and the lower wells. A method for assembling the filtration apparatus comprises supporting the lower plate, disposing a filter medium in the lower well, disposing the upper plate at the lower plate such that the lower wells substantially register with the upper wells, and compressing the upper plate onto the lower plate to form an interference fit between the lower well and the upper well.