Assessment of the physicochemical and bacteriological quality of wastewater

Abstract

This study focused on evaluating the physicochemical and bacteriological quality of raw and treated wastewater from the Ain Témouchent wastewater treatment plant (WWTP), based on five samples (S1 to S5). Microbiological analyses were conducted using the Most Probable Number (MPN) method, alongside standardized physicochemical testing. The physicochemical results showed that pH values ranged between 7 and 8.28. The average temperature was 15.4 °C for raw wastewater and 10.8 °C for treated water. Turbidity exhibited a significant decrease, with a reduction exceeding 97%, reaching values below 4 NTU in the majority of treated samples. Conductivity showed a slight decrease after treatment. The average nitrite concentration was reduced from 0.199 mg/L in raw wastewater to 0.051 mg/L in treated water. Conversely, nitrate concentrations increased after treatment, rising from 0–0.88 mg/L in raw samples to 0–4.2 mg/L in treated effluents, a phenomenon attributed to the nitrification process. Ammonium levels experienced a substantial reduction, with an initial average concentration of 69.08 mg/L in raw wastewater. Phosphate concentrations slightly decreased following treatment. From a bacteriological perspective, a significant reduction in total coliforms was observed after treatment, indicating partial effectiveness of the treatment process. The treatment process at the Ain Témouchent WWTP ensures a highly effective reduction of organic pollution, with results conforming to standards for most analyzed physicochemical parameters. However, the insufficient removal of fecal coliforms highlights the need to optimize or supplement the treatment, notably by adding a disinfection step, to guarantee the sanitary quality of the effluents for potential reuse.