Tertiary treatment of the wastewater removes

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tertiary treatment of the wastewater removes

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LectureNotes said tertiary treatment of the wastewater removes

Answer:
Tertiary treatment of wastewater is an advanced cleaning process utilized after secondary treatment to further purify the water. Here is a detailed explanation of what tertiary treatment removes from wastewater:

  1. Nutrients:

    • Nitrogen and Phosphorus:
      Tertiary treatment focuses on removing nutrients such as nitrogen and phosphorus, which are not adequately removed during primary and secondary treatments. Excessive amounts of these nutrients can lead to eutrophication, causing algal blooms in water bodies, which can be detrimental to aquatic ecosystems.

      \text{Chemical reactions to remove Phosphorus: } \text{PO}_4^{3-} + \text{Al}^{3+} \rightarrow \text{AlPO}_4

      \text{Biological removal of Nitrogen through nitrification and denitrification processes:}

      \text{Nitrification: } \text{NH}_4^+ + \text{O}_2 \rightarrow \text{NO}_3^{-} + 2\text{H}^+ + \text{H}_2\text{O}

      \text{Denitrification: } \text{NO}_3^{-} \rightarrow \text{N}_2 \uparrow + 2\text{O}_2

  2. Suspended Solids:

    • Fine Particulate Matter:
      Tertiary treatment includes filters that capture fine suspended particles which were not removed during secondary treatment. Filtration techniques such as sand filtration, membrane filtration, and microfiltration are often used.

  3. Microbial Pathogens:

    • Bacteria, Viruses, and Protozoa:
      Disinfection processes in tertiary treatment, such as chlorination, ultraviolet (UV) irradiation, and ozonation, are employed to kill or render harmless any remaining microbial pathogens.

      \text{Ozone Disinfection: } 2\text{O}_3 \rightarrow 3\text{O}_2

      \text{Chlorination: } \text{Cl}_2 + \text{H}_2\text{O} \rightarrow \text{HCl} + \text{HOCl}

  4. Dissolved Organic Compounds:

    • Organic Chemicals:
      Advanced oxidation processes (AOPs) like ozone, hydrogen peroxide, and UV light can break down dissolved organic compounds that may be harmful or persistent. Activated carbon adsorption is another common method in tertiary treatment to remove these organic contaminants.

      \text{Hydrogen Peroxide Treatment: } \text{H}_2\text{O}_2 + \text{UV} \rightarrow 2\text{OH} \cdot

  5. Heavy Metals:

    • Mercury, Lead, Cadmium:
      Some tertiary treatment methods, including chemical precipitation, ion exchange, or advanced oxidation, are designed to remove heavy metals from wastewater which can be toxic to the environment and human health.

  6. Pharmaceuticals and Endocrine Disruptors:

    • Trace Organic Contaminants:
      Advanced treatments like reverse osmosis and advanced oxidation can help in removing pharmaceutical residues and endocrine-disrupting compounds present in trace amounts.

Final Answer:
Tertiary treatment of wastewater removes nutrients (nitrogen and phosphorus), fine suspended solids, microbial pathogens (bacteria, viruses, and protozoa), dissolved organic compounds, heavy metals, and trace organic contaminants such as pharmaceuticals and endocrine disruptors. This advanced treatment ensures that the treated water is safe for various applications, including discharge into sensitive environments, irrigation, industrial use, or even potable water reuse after further polishing.

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