Climate change, rapid urbanization, and draughts continue to intensify the issue of water scarcity in the coastal areas of Algeria, making the reuse of treated wastewater a highly relevant alternative for the sustainable management of water resources. On the other hand, inefficient performance can pose a danger to the environment with respect to wastewater reuse. The current study investigates the monthly variation in essential physicochemical values in the treated wastewater discharged from the El Kerma Wastewater Treatment Plant located in Oran, Algeria, with the objective of determining its reuse potential. The effluent exhibited the following concentration ranges: pH (7.06–7.87), TSS (15–34 mg/L), COD (52.55–91.14 mg/L), BOD₅ (12–32 mg/L), PO₄3⁻ (0.22–5.25 mg/L), NO₂⁻ (0.09–0.16 mg/L), NO₃⁻ (0.36–0.83 mg/L), NH₄⁺–N (0.1–32.6 mg/L), Zn2⁺ (0.07–0.28 mg/L), and Cu2⁺ (0.002–0.17 mg/L). Most physicochemical parameters complied with Algerian and international regulatory limits for urban reuse, reflecting effective removal of suspended solids and organic matter (average removal efficiencies of ~ 90% for TSS and ~ 95% for BOD₅). However, the BOD₅/COD ratio (~ 0.2) indicated poor biodegradability and the persistence of recalcitrant organic compounds. Compared to international standards for agricultural reuse (US EPA, WHO, FAO), there are some significant limitations. While the levels of pH, nitrate, nitrite, zinc, and copper are within irrigation standards, high electrical conductivity, ammonium, phosphate, and organic load make it not suitable for unrestricted agricultural irrigation of raw-consumed crops. Also, the levels of phosphates are above the stringent reuse standards of more than 80% of the samples, posing a significant risk of eutrophication to the receiving ecosystems, whereas levels of ammonium are regularly above the international agricultural reuse standards, potentially having some adverse impacts on plant growth and soil quality. Besides, while copper and zinc are within the irrigation standards, they are above the levels of ecological protection for freshwater organisms, suggesting some potential long-term ecological impacts. Overall, the El Kerma WWTP effluent is suitable for restricted agricultural reuse (non-food crops, fodder, and industrial crops) but poses risks for sensitive aquatic ecosystems and food-chain safety if discharged or reused without additional treatment. These findings highlight the urgent need for improved tertiary treatment and stricter reuse management strategies to ensure environmentally safe wastewater reuse in semi-arid Mediterranean regions.

Assessment of wastewater quality and agricultural reuse risks in Oran, Northwestern Algeria

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发表日期：

2026年4月14日

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Abdessamed Mahboubi,
Ali Kherraz,
Anas Mami

摘要

Climate change, rapid urbanization, and draughts continue to intensify the issue of water scarcity in the coastal areas of Algeria, making the reuse of treated wastewater a highly relevant alternative for the sustainable management of water resources. On the other hand, inefficient performance can pose a danger to the environment with respect to wastewater reuse. The current study investigates the monthly variation in essential physicochemical values in the treated wastewater discharged from the El Kerma Wastewater Treatment Plant located in Oran, Algeria, with the objective of determining its reuse potential. The effluent exhibited the following concentration ranges: pH (7.06–7.87), TSS (15–34 mg/L), COD (52.55–91.14 mg/L), BOD₅ (12–32 mg/L), PO₄³⁻ (0.22–5.25 mg/L), NO₂⁻ (0.09–0.16 mg/L), NO₃⁻ (0.36–0.83 mg/L), NH₄⁺–N (0.1–32.6 mg/L), Zn²⁺ (0.07–0.28 mg/L), and Cu²⁺ (0.002–0.17 mg/L). Most physicochemical parameters complied with Algerian and international regulatory limits for urban reuse, reflecting effective removal of suspended solids and organic matter (average removal efficiencies of ~ 90% for TSS and ~ 95% for BOD₅). However, the BOD₅/COD ratio (~ 0.2) indicated poor biodegradability and the persistence of recalcitrant organic compounds. Compared to international standards for agricultural reuse (US EPA, WHO, FAO), there are some significant limitations. While the levels of pH, nitrate, nitrite, zinc, and copper are within irrigation standards, high electrical conductivity, ammonium, phosphate, and organic load make it not suitable for unrestricted agricultural irrigation of raw-consumed crops. Also, the levels of phosphates are above the stringent reuse standards of more than 80% of the samples, posing a significant risk of eutrophication to the receiving ecosystems, whereas levels of ammonium are regularly above the international agricultural reuse standards, potentially having some adverse impacts on plant growth and soil quality. Besides, while copper and zinc are within the irrigation standards, they are above the levels of ecological protection for freshwater organisms, suggesting some potential long-term ecological impacts. Overall, the El Kerma WWTP effluent is suitable for restricted agricultural reuse (non-food crops, fodder, and industrial crops) but poses risks for sensitive aquatic ecosystems and food-chain safety if discharged or reused without additional treatment. These findings highlight the urgent need for improved tertiary treatment and stricter reuse management strategies to ensure environmentally safe wastewater reuse in semi-arid Mediterranean regions.