Discussion Questions

1. Describe the Cyclic Activated-Sludge System, discuss its mode of operation and the potential benefits as an equipment option for an activated sludge unit to be designed into a batch wastewater pretreatment system.

2. You are a consultant who has been hired by a city to help reduce organic matter in their system while improving the dissolved oxygen concentration and deriving an optimal sludge to ultimately bag and sell as an agricultural soil conditioner. Explain the chemistry necessary to properly digest the waste during the aerobic digestion process in order to maximize effluent oxygen concentrations in the water while deriving higher concentrations of nitrate, nitrite, sulfate, and phosphorus in the final sludge product.

3. You are a consultant who has been hired by a city to help reduce organic matter in their system while improving the dissolved oxygen concentration and deriving an optimal sludge to ultimately bag and sell as an agricultural soil conditioner. What equation(s) would you use to calculate the number of days the sludge must remain in the anaerobic digester in order to maximize volatile organic digestion and still produce a favorable sludge high in nitrogen and phosphorus? Be sure and explain the chemistry behind your equation selections.

4. Describe the design considerations inherent in a completely engineered biological oxidation unit. Be sure and describe every aspect of the unit relevant to the design considerations.