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Sludge volume from sedimentation tank, 10 MLD

Short answer

Dry solids removed: 1500 kg/d. Sludge volume at 95% moisture and sp. gr. 1.02 is 29.4 m³/d.

Determine the volume of sludge produced in a sewage sedimentation tank from the following data: Flow rate = 10 million liters/day; Suspended solids content in raw sewage = 250 mg/l; Sedimentation tank removes 60% of suspended solids; Specific gravity of sludge = 1.02; Moisture content of sludge = 95%.

Volume of sludge V=Wsρw Gsl (1−p)V = \dfrac{W_s}{\rho_w \, G_{sl}\,(1-p)}

  • Solids in raw sewage: 10×106 L/d×250 mg/L=250010\times10^6\ \text{L/d} \times 250\ \text{mg/L} = 2500 kg/d
  • Solids removed (60%): Ws=1500W_s = 1500 kg/d
  • Solids fraction of sludge: 1−0.95=0.051 - 0.95 = 0.05
V=15001000×1.02×0.05=29.41 m3/dV = \frac{1500}{1000 \times 1.02 \times 0.05} = 29.41\ \text{m}^3\text{/d}

Answer: volume of sludge ≈29.4 m3\approx 29.4\ \text{m}^3 per day.

✓ Answer checked by Claude Opus 5.5 (high effort)

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