environmental performance assessment of three municipal wastewater treatment plants in Al-Najaf, Iraq using the CCME water quality index (CCME-WQI)
DOI:
https://doi.org/10.55287/22275398_2026_58_82-96Keywords:
CCME-WQI, municipal wastewater, wastewater treatment plants, effluent quality, Euphrates River, Iraq, Al-NajafAbstract
This study evaluated the environmental performance of three municipal wastewater treatment plants in Al-Barakia, Al-Najaf, Iraq, namely WWTP Old Al-Najaf, WWTP Bio-Shaft, and WWTP Compact Unit, using the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI). Wastewater samples were collected monthly from influent and effluent streams from January to December 2025. The assessment was based on six selected physicochemical parameters, namely BOD₅, COD, TSS, pH, NH₃, and PO₄³⁻, in accordance with the Iraqi Standards for Water Quality (IQS, 2009). The results showed that the influent wastewater at all three plants was classified as poor, with CCME-WQI values of 20.31, 21.85, and 21.60 for WWTP Old Al-Najaf, WWTP Bio-Shaft, and WWTP Compact Unit, respectively. After treatment, water quality improved at all plants; however, the degree of improvement varied. The treated effluent of Old Al-Najaf remained poor (44.17), whereas Bio-Shaft (76.93) and Compact Unit (71.76) improved to the fair category. Descriptive statistics of the treated effluents showed that mean BOD₅, COD, TSS, and pH generally complied with Iraqi limits, while NH₃ and PO₄³⁻ remained the principal limiting parameters, particularly in Old Al-Najaf and Compact Unit. Overall, the study confirms that CCME-WQI is an effective tool for evaluating treatment performance and differentiating the operational status of municipal wastewater treatment plants under Iraqi conditions.
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