How does nitrification affect alkalinity in waste water?

Nitrification affects alkalinity in wastewater primarily through the conversion of ammonia (NH3) to nitrate (NO3-). This biological oxidation process is conducted by nitrifying bacteria and takes place in two steps: first, ammonia is oxidized to nitrite (NO2-), and then nitrite is further oxidized to nitrate.

During this process, there is a consumption of alkalinity due to the release of protons (H+) into the solution. For each mole of ammonia that is nitrified, two moles of protons are generated, which leads to a decrease in the pH of the wastewater and results in a reduction of alkalinity. Alkalinity is largely a measure of the buffering capacity of water, and when protons increase, it diminishes the ability of the water to neutralize acids, effectively removing available alkalinity.

Therefore, the correct understanding of the relationship is that nitrification actively reduces alkalinity due to the biochemical reactions involved.