To achieve a minimum solids content of 15-20% for sludge disposal, municipal sludge must be dewatered to what range?

To achieve a minimum solids content of 15-20% for sludge disposal, municipal sludge must be dewatered to what range?

• A. 5-10%
• B. 15-20%
• C. 25-30%
• D. 35-40%

Answer: (B)

Removing water through dewatering concentrates the solids in sludge, making it heavy enough to handle and much smaller in volume for disposal. For municipal sludge, a minimum of about 15–20% dry solids is typically required so the material is solid enough to be pumped, transported, and disposed without creating excessive leachate or handling problems, while not incurring unnecessary costs from over-dewatering. If the sludge were only 5–10% solids, it would remain too watery and bulky, increasing transport and disposal costs. Pushing solids higher to 25–30% or 35–40% would demand more energy and equipment without adding needed benefit for standard disposal routes.

Removing water through dewatering concentrates the solids in sludge, making it heavy enough to handle and much smaller in volume for disposal. For municipal sludge, a minimum of about 15–20% dry solids is typically required so the material is solid enough to be pumped, transported, and disposed without creating excessive leachate or handling problems, while not incurring unnecessary costs from over-dewatering. If the sludge were only 5–10% solids, it would remain too watery and bulky, increasing transport and disposal costs. Pushing solids higher to 25–30% or 35–40% would demand more energy and equipment without adding needed benefit for standard disposal routes.