This lowered oxygen may kill fish and other aquatic life. Reduction of fecal coliform in wastewater may require use of chlorine and other disinfectant chemicals. Such materials may kill the fecal coliform and disease bacteria. They also kill bacteria essential to the proper balance of the aquatic environment, endangering the survival of species dependent on those bacteria. So, higher levels of fecal coliform require higher levels of chlorine, threatening those aquatic organisms.
Membrane filtration is the method of choice for the analysis of fecal coliforms in water.
The microorganisms present in the water remain on the filter surface. When the filter is placed in a sterile petri dish and saturated with an appropriate medium, growth of the desired organisms is encouraged, while that of other organisms is suppressed. Each cell develops into a separate colony, which can be counted directly, and the results calculated as microbial density. This elevated temperature heat shocks non-fecal bacteria and suppresses their growth. The Coli Chrome' 2 redigel medium is a new and patented formulation for water testing.