The largest energy consumer in a conventional wastewater treatment plant (WWTP) is aeration for biological removal of contaminants. Also known as the activated sludge process, aeration is required to aid in removal of biochemcial oxygen demand (BOD) and nutrients. Across the US, new regulations are being implemented which require a higher removal of nutrients, specifically nitrogen. Reducing the amount of aeration in WWTP directly effects the conversion of ammonia to nitrate, or nitrification.

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... ecent research demonstrates the potential for nitrification at lower dissolved oxygen (DO) concentrations. However, under low DO conditions, nitrous oxide (N 2 O) can form due to incomplete nitrification. Nitrous oxide is a potent greenhouse gas, and induces greater environmental damage than carbon dioxide in the atmosphere. Thus, nitrous oxide requires monitoring and potentially capturing the nitrous oxide emissions. Testing an activated sludge system at various low DO concentrations will determine a range of DO concentrations where it is possible to maximize nitification without harming the environment due to excess nitrous oxide production.