Question

Why does the Howard Curren use pure oxygen for the activated sludge process?

Answer 1

The resulting facilities include the following:

• Pre-aeration for hydrogen sulfide stripping and odor control. Hydrogen sulfide levels influent to the odor control system sometimes approach 1200 mg/L.
• Step-feed improvements to oxygen activated sludge reactors and conversion of the facilities to the first stage of a two-stage system.
• Conversion of aerobic digestion tanks to wastewater reactors using fine bubble diffusers. The converted tanks serve as the nitrification stage following carbonaceous treatment in the first-stage, oxygen system.
• New deep-bed denitrification filters.
• A major expansion to the plant's maintenance building.
• A new 27,000-sf administration building to house laboratories and plant administrative offices.
• A standby power facility with four 2000-KW engine generators.
• Co-generation facilities featuring five 500-KW engine generators using sludge gas as the fuel.
• Digested sludge is dewatered using belt filter presses and converted to biosolids using heat drying.

One of the key design features of the plant is the philosophy of providing flexibility. For example, the oxygen activated sludge system can be operated in parallel or in series with the conventional activated sludge system. Also, denitrification at the filters can be supplemented by denitrification in the activated sludge system. This flexibility allows the operators the tools to adjust to various conditions.