Treatment of wastewater refers to removing all harmful and wasteful substances through chemical processes to obtain water that can be reutilized. In this paper, I will compare the secondary treatment to the tertiary treatment of wastewater.
Secondary and Tertiary treatment of wastewater
After the wastewater has passed through the primary treatment, in which most of the suspended solid materials are removed, it then goes through a series of biological processes; this being the secondary treatment stage. In this stage, microorganisms such as bacteria are used to feed on and break down the organic substances in the wastewater. Those broken down substances along with the bacteria are collected as sludge. (CPPIC-Glossary-secondary treatment); (water water secondary treatment)
The third treatment stage is Tertiary of Advanced treatment of wastewater. Water coming from the second stage through the aerated tanks may not be completely suitable for reuse. It may still have suspended substances or other chemicals which further need to be removed. There may also be chemicals that need to be added to the effluent water. This is the job of the tertiary treatment processes. It will remove substances such as phosphorous or perhaps add chlorine. It may also involve ultraviolet radiation to make the water suitable for reuse purposes. (Water treatment and management)
Uses of reclaimed water
Reclaimed water can be of great advantage to our society, especially in areas where there is a shortage of freshwater supply. Some areas use reclaimed water for purposes where health risks are not involved such as nonpotable uses; these may include cleaning, irrigation, toilets, fire fighting, and cooling water in industries. (Reclaimed utilization)
The use of reclaimed water for purposes such as drinking, bathing, and cooking is questionable in certain areas. People feel that the treated water because it has gone through such severe stages of chemical and biological treatments, may have some health risks. However, in other areas, if the water has been through advanced treatment, people feel it is good to be used for drinking and cooking. (Household reclaimed water).
What treatment must be used if reclaimed water is for drinking purposes?
If after the treatment of wastewater, it is being recharged into the ground and then being used for drinking purposes, I would say that tertiary treatment methods should be used. The main reason is that primary and secondary treatment may not be successful in removing all the waste, and since the water is being used for drinking purposes, it needs to be completely harmless. For example, if the wastewater contains chemicals such as phosphorous, then secondary treatment will be unable to remove those, hence making it harmful for drinking.
Furthermore, in the tertiary treatment, if the disinfection process is included, this makes the water safer for drinking. It will remove the microorganisms which may be there in the water due to the previous treatments it went through. This stage will ensure that safe water is being recharged into the ground for various purposes. Hence, I feel that secondary treatment of wastewater is not enough to make the reclaimed water safe for drinking purposes, since health risks are involved, it is always best to ensure that wastewater passes through all three stages of treatment, along with disinfection, before it used again.
Works Cited
CPPIC-Glossary-secondary treatment. Web.
Household Reclaimed Water. 2009. Web.
Reclaimed Utilization. Web.
Water Treatment and Management. 2009. Web.
Waterwater Secondary Treatment. Web.