Page 185 - AJWEP-v22i3

Maghnia wastewater and risk assessment

NO 3 ⁻ concentration is estimated to be 0.355 – 0.425 mg The average nitrate removal efficiency was 56.58%,
N/L, while that of the effluent is 0.194 – 0.346 mg (Figure 11B) indicating moderate denitrification
N/L. The non-overlapping nature of the CIs reinforces performance. Nevertheless, the treated water from the
the statistical significance of the observed reduction. Lagfafe WWTP remains suitable for agricultural reuse,
However, the effluent exhibits greater variability (SD: given the absence of regulatory restrictions on NO₃⁻
0.26 mg N/L) than the influent (SD: 0.12 mg N/L), concentrations and its agronomic value.
indicating increased fluctuation in NO 3 ⁻ levels after
treatment. 3.10. Conductivity

Table 11. NO 3 ⁻ concentration in the inflow and outflow wastewater
Wastewater NO 3⁻ (mg N/L)
Average Maximum Minimum Median SD 95% CI
Inflow 0.39 0.65 0.27 0.40 0.12 0.355 – 0.425
Outflow 0.27 0.98 0.05 0.16 0.26 0.194 – 0.346
Note: The p-value was calculated to be 0.0028.
Abbreviations: CI: confidence interval; SD: standard deviation; NO3⁻: nitrate.

A

B

Figure 12. (A) Variations in the conductivity of inflow and outflow wastewater at the Lagfafe wastewater
treatment plant. (B) Variations in removal efficiency % of conductivity at the Lagfafe wastewater treatment
plant.

Volume 22 Issue 3 (2025) 179 doi: 10.36922/AJWEP025120085