Wastewater from coal washing containing roughly 3% suspended solids (such as clay, slate, and stone) undergoes treatment to achieve what outcome ?
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Answer: B. In sedimentation tanks equipped with mechanical scrapper
Explanation
Coal washing wastewater contains heavy suspended solids that settle out efficiently in mechanical sedimentation tanks. Sedimentation tanks equipped with mechanical scrapers continuously collect and remove the settled coal sludge. Gravity settling is the most practical method for clarifying high-volume industrial wash water suspensions. Coal preparation plants generate large volumes of wastewater laden with fine clay, slate, and stone particles. Mechanical scrapers rotate slowly along the bottom of clarifiers to push accumulated sludge toward discharge points. Clarification reduces suspended solid concentrations before the treated water is recycled or safely discharged.
Mining operations utilize closed-loop water systems to conserve precious water resources and prevent environmental pollution. Efficient solid-liquid separation prevents the silting of natural rivers and protects downstream aquatic habitats. Industrial thickeners and clarifiers are standard equipment used across the minerals processing and mining sectors. Chemical coagulation is sometimes used as a secondary polishing step rather than the primary bulk solids removal. Vacuum filters handle thickened sludge dewatering rather than treating raw, high-volume coal washing wastewater directly. Clarifiers describe the general category of tanks, but sedimentation tanks with scrapers specifically name the mechanism.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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