The waste water treatment must be a priority for all ecology – friendly governments and factories. First, protect public health and the environment, and secondly, that treated water reuse for other purposes. The main reason for treating wastewater is to protect public health and the environment. If wastewater is not treated and discharged directly into rivers, lakes or seas.
It is quite likely introduce elements of pollution that end up causing significant ecological damage to the surrounding environment and public health diseases (caused by viruses and bacteria) in people and communities that come into contact with these contaminated waters.
Another important reason is the reuse of these waters. Some human activities that need water consumption do not require potable water we speak, for example, the irrigation of green areas or water used for industrial application or service (cleaning industrial areas, car washing, among others).
The wastewater treatment can be classified according to many variants, a fairly common is discussed here, which refers to operations and unit processes are grouped together, thereby is important to establish a distinction between preliminary treatment, primary, secondary and tertiary treatment.
Preliminary treatments are not a process itself, but they’re used to increase the effectiveness of other treatments. Preliminary treatments include using sieves, gratings or microfilters to rule the bulkier and abrasive objects. Microfilters and sieving particles are discarded while small bars are used for larger objects.
Once applied this type of preliminary treatment, the next step are the primary treatments. The main objective in this step is to remove those solid contaminants that may or those who are floatable, such as fats. The best known primary treatments are primary sedimentation and coagulation.
Then we proceed with the secondary treatments, which aim to reduce biological oxygen demand aka BOD that escapes primary treatment. This means that we must continue reducing the level of nutrients and water contaminants to enable their discharge to natural means. Some methods used in these treatments are: activated sludge, impoundment and biological filter.