In water and wastewater treatment process a filtration device may be used to remove water from the sludge formed by the precipitation reaction. The initial concentration of sludge from softening reaction is 2% (20,000 mg/L) and the volume of sludge is 100 m3. After filtration the sludge solids concentration is 35%. Assume that the sludge does not change density during filtration and that liquid removed from the sludge contains no sludge. Using mass-balance method. determine the volume of sludge after filtration. Assume steady state.