Wastewater Treatment

When natural water has been used for human consumption, industrial or agricultural use, are added a series of physical contaminants, chemical and biological agents that give the resulting water WASTEWATER character.

The wastewater (also called black water, wastewater or sewage), without wastewater treatment techniques, are important sources of pollution to the stream where wastewater are discharged and could cause: aromas and flavors, wildlife toxicity, infections caused by pathogenic microorganisms, negative visual impact, thermal pollution and eutrophication of receiving water.
Supplemented the wastewater treatment with reuse water treatment, it is obtained reclaimed water which complies with adequate health guarantee for future use.

As a first classification of the wastewater can be differentiated between:

  • Urban water: Including water from domestic activities (food, home cleaning, etc), public cleaning water, water from shops and industries as well as runoff stormwater.
  • Industrial water: Including industrial process water (as varied as the different types of industries that create it) often this type of water are mixed with domestic sewage coming from industries, cleaning water or stormwater at industry.
Wastewater characterization it is possible obtained its physical, chemical and biological composition, providing the information needed to properly design the wastewater treatment. The most significant parameters at the characterization of the wastewater are:
  • Suspended and dissolved solids (S.S.). Solids concentration from organic, inorganic and mineral matter present in wastewater.
  • Biological Oxygen Demand (BOD). Amount of dissolved oxygen used by microorganisms to decompose organic matter in the wastewater. This parameter indicates the biodegradability of wastewater.
  • Chemical Oxygen Demand (COD). Amount of dissolved oxygen required to oxidize organic matter in the wastewater, through a strong oxidizer. Is a parameter representing the amount of non-biodegradable organic matter, or the presence of compounds that inhibit the action of microorganisms.
  • pH. It measures the acidity or basicity of wastewater, and is a key parameter which we must control for the effectiveness of the wastewater treatment process.
  • Oils and fats. Its form a film on the surface of the water and reduce the oxygen transfer is complicated biological activity.
Notice: When water comes only from urban origin, could be estimated the flow (typically 200 l / person per day) and composition of wastewater. For an industrial wastewater, although there are references to many types of industry, it is necessary to have specific data on flow and composition, because these values vary even for the same type of industry in terms of their production process.