Civil Engineering PE

Answer: D - Typically, drying beds, lagoons, and tanks are considered to be appropriate facilities in which to store sludge at mechanical wastewater treatment plants. These facilities may be used to store liquid or dried sludge. The design considerations for sludge storage facilities include odor controls for storage tanks, and aeration units and covers for lagoons. A minimum of 120 to 180 days of storage capacity is commonly required for the design life of the plant. Specific design requirements for sludge storage facilities are set by state regulating agencies.