These samples are collected from this plant, the South Water Purification Plant, the 12 water pumping stations, and from required sampling sites in the distribution system. In addition, samples are taken from various location in Lake Michigan to monitor the lake for various indices of pollution. The microbiologists in this laboratory are primarily concerned with the detection of sewage pollution in which disease carrying typhoid and dysentery bacteria could be present. This is done by looking for two specific groups of microorganisms, coliform and fecal strep, which are indicators of pollution. We also monitor Lake Michigan for cryptospoidium.
Microbiologists also examine samples for organisms called plankton, or algae.
Some of these organisms may cause objectionable tastes and odors, while others are significant because they clog filters and require modification of purification processes. The Laboratory's Microscopy Unit uses electron microscopes capable of magnification in excess of 250,000 times. They are used in special studies for microorganism identification, particle research, and chemical analyses of minute samples. A complete water analysis is performed four times each year on samples taken from Lake Michigan, the filtration plants, and the Distribution System. Each of these samples is analyzed for 50 parameters to provide a profile of water quality.