Wastewater treatment involves removing solids by allowing them to settle, and using chemical and biological processes to further purify the water. Disinfection, often with chlorine, is common, but many states require dechlorination before discharge to protect aquatic life. Treated wastewater can be reused for industrial, agricultural, and recreational purposes or to replenish groundwater.

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Chemicals play a crucial role in wastewater treatment by aiding in the removal of contaminants, disinfecting water, and improving efficiency. Here’s how they are used:

• Sludge Treatment – Aluminum and iron based coagulants along with various polymers are used to thicken and stabilize sludge, making it easier to handle and dispose of safely.

• pH Adjustment – Acids (e.g., sulfuric acid) or bases (e.g., sodium hydroxide) are used to balance pH levels to optimize treatment processes and protect equipment.

• Disinfection – Chlorine and chlorine dioxide are used to kill harmful bacteria, viruses, and other pathogens before the water is discharged or reused.

• Dechlorination – After chlorination, chemicals like sodium bisulfite and sodium thiosulfate are added to neutralize excess chlorine, protecting aquatic life.

• Odor Control – Chemicals such as hydrogen peroxide, permanganate and chlorine dioxide help reduce unpleasant odors from wastewater.

• Phosphorus and Ammonia Removal

 

These chemical processes work alongside physical and biological treatments to ensure wastewater is effectively cleaned and safe for discharge or reuse.