# What is total nitrogen?

Jun 4, 2017

Total nitrogen ($\text{TN}$) is the sum of ammonia nitrogen ($\text{NH"_3"-N}$), nitrate
nitrogen ($\text{NO"_3"-N}$), nitrite nitrogen ($\text{NO"_2"-N}$), and organically bonded nitrogen.

#### Explanation:

All measurements are expressed as the concentration of $\text{N}$ in the sample.

$\text{NH"_3"-N}$ is a constituent of raw domestic wastewater.

Various biological processes oxidize the ${\text{NH}}_{3}$ to $\text{NO"_2^"-}$ and $\text{NO"_3^"-}$.

Typical concentrations in wastewater are $\text{TN = 30 mg/L}$ and $\text{NH"_3"-N = 15 mg/L}$.

The numbers vary with the jurisdiction, but a common limit for $\text{NH"_3"-N}$ in the effluent after treatment is 1.25 mg/L.