Sludge is a semi-solid, slurry type of material that is produced from manufacturing, industrial wastewater or from any type of water treatment process. Sludge tanks are common in industrial applications as well as for city use in sewage treatment processes. These tanks have to be strong enough to contain the weight and pressure of the water as well as the semi-solid material to avoid leaks, spills and environmental disasters.
For large industrial and sewage or wastewater treatment facilities sludge tanks are essential as a step in sewage treatment. It is essential for the semi-solid material to be removed from the water and then reduced to its smallest volume. This is the same process as is used in a residential septic system, just on a much larger scale.
However, in industrial and wastewater treatment sludge tanks other harmful compounds or chemicals, including the inorganic heavy metals, may also be present. Processing these organic or inorganic hazardous materials, or holding them in the sludge tank for processing, is essential in protecting the environment.
Anaerobic and Aerobic Processes
In the sludge tank anaerobic digestion, the action of bacteria breaking down the materials in the liquid, is an ongoing process. The process is done without the need for oxygen.
In addition there is also aerobic breakdown or digestion of organic matter. This requires the presence of oxygen and produces carbon dioxide as a byproduct. This also requires additional oxygen to be introduced into the sludge tank to facilitate the growth and action of the aerobic bacteria.
As the water is removed from the semi-solid material the thick, heavy yet still wet material can be removed from the sludge tank. This material is then typically allowed to dry in beds or processed to press out the remaining water and create a dry material that is then disposed of according to EPA standards in landfills or through other disposal methods.
Sludge storage tanks come in a variety of sizes, shapes and designs based on the amount of material you need to hold or process. For slurries and earth containment there are also specialized retainer systems that are much faster to construct and install than traditional forms of containment.