Clogging Up Progress

A leach field drain pipe was constantly clogging. Quite often, fluid handling systems dealing with aqueous solutions which experience basic pH upsets will have a problem with the precipitation of calcium carbonate. When this sample was first examined with Polarized Light Microscopy, the optical properties and crystal morphology of the particles obtained from inside the pipe did not match those of calcium carbonate. 

The sample was then examined using a Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer. The high energy electron beam in the instrument puts the atoms in the sample particles in a higher energy excited state. In order to return to a lower energy state, they emit energy in the form of photons. These photons are high enough in energy that they are in the X-ray region of the electromagnetic spectrum. The wavelengths of these X-rays are specific for each element in the periodic table. The intensity of the signal is also proportional to each atom’s concentration. For this sample, the material clogging the pipe was found to be magnesium phosphate, Mg3(PO4)2.