Microbiology and Membrane Treatment of Wastewater

        The treatment of wastewater with microorganisms is a very common technique within industry. The wastewater produced by industries contains many contaminants (biproducts of the process, high temperature water, process chemicals, etc...) which may be harmful to the surrounding environment. These contaminants must be removed so as to comply with EPA standards. Through the use of several steps, the effluent water can be purified and made acceptable for introduction into the surroundings.

        The primary step used by industry and domestic wastewater treatment is chemical flocculation/sedimentation which removes the large particles that are suspended in the effluent. However, the waste stream still may contain soluble organic material that may be harmful to the environment. The removal of the biodegradable organic materials may be accomplished through the use of an sludge digestion process.

There are two types of sludge digesting processes:

  • Aerobic Digestion

  •            -requires a large amount of oxygen to degrade contaminants to disposable
                 materials through an oxidation process

  • Anaerobic Digestion
  • Pros/Cons for the Two Processes
  • To achieve the greatest removal of contaminants from the waste stream by the most cost-effective method, the best cultures of bacteria and microorganisms must be selected for use in the digester. This is accomplished through Bioaugmentation.

            Another step performed by treatment plants to further purify the wastewater is through the use of membranes to filter out the dissolved solids which remain in the effluent. The common method used for this step is Reverse Osmosis


    (c)1997 Paul Kroncke and Tom Mistretta - Intro to Biochemical Engineering Term Project