Comparison of N and P Er and outlet concentration values

The objective is to show how applying only the pIs is not enough to establish whether a process is critical or not. Is the case of the S6 WWTP, critical for the N-removal process, as presented in Table 10 (columns 1–2, Table 10).
Table 10.
After the more detailed investigation (summarized in columns 3–5 of Table 10), S6 was found to be not critical, revealing its potential ability to remove nitrogen.