Sewage treatment operations frequently utilize which coagulant_________________?
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Answer: B. Ferric chloride
Explanation
Ferric chloride is widely utilized as an effective coagulant in wastewater treatment processes to precipitate suspended solids. Coagulation chemistry relies on multivalent iron ions to neutralize negatively charged colloidal particles. Precipitation forms heavy floc structures that settle rapidly out of the liquid suspension. Wastewater treatment plants add chemical coagulants to enhance clarification and remove phosphorus. Colloidal particles in sewage remain suspended indefinitely due to electrostatic repulsion forces. Coagulation and flocculation precede sedimentation stages in advanced treatment facilities.
Municipal water resource recovery facilities use chemical coagulants to meet stringent discharge standards. Proper chemical dosing optimizes treatment efficiency and reduces sludge production volumes. Operators monitor pH and alkalinity levels to ensure optimal performance of iron-based coagulants. Option A alum is commonly used in potable water treatment rather than primary wastewater coagulation. Option C ferric sulphate is another coagulant but ferric chloride is frequently selected for specific wastewater loads. Option D chlorinated copperas is an older chemical combination largely superseded by modern ferric salts.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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