• Energy Research

The study aimed to determine Aluminum sludge composition and structure for its valorisation as an alternative natural material for heavy metals removal from wastewater for further reuse as treated water in different applications. The study was conducted to investigate the introduction of Al-bearing sludge composition. The physical and chemical properties were examined using X-ray diffraction tests (XRD), scanning electron microscope tests (SEM), Fourier-transform infrared tests (FTIR), and Brunauer-Emmett-Teller tests (BET). Furthermore, the heavy metal concentrations of synthetic wastewater were measured using the spectrophotometry method. The experimental procedure is based on testing different pH limits and amounts of aluminum sludge to find the optimum conditions for copper (Cu) and zinc (Zn) removal. The results demonstrated a high removal efficiency where its value reached up to 97.4% and 96.6% for Zn and Cu, respectively, in an acidic medium (pH = 6) using a relatively high amount of sludge (1400 mg). Nevertheless, a low efficiency was obtained in the strongly acidic medium (pH = 4) and a smaller sludge amount of about 480 mg.

Water pollution reduces the availability of fresh water, especially in arid areas suffering from water stress, and also adversely affects soil, vegetation and environmental processes. Wastewater treatment processes aim to reduce environmental degradation and increase water availability by improving the quality of wastewater to a standard suitable for irrigation. This paper compares the performance of three wastewater treatment processes: (i) aerated lagoon (AL), (ii) activated sludge (AS), and (iii) constructed wetland (plant beds, PB) under the arid climate of Algeria. The statistical analysis focused on the comparison between the removal rates of the physical (SS) and biological pollution (BOD5 and COD) parameters in the three stations during 8 years of operation. Obtained results show that the maximum removal rates were observed in the AS process and the minimum were in the AL process. The comparison between the removal rates for a given parameter has shown that there is a significant difference between the AL process on the one hand and the AS and PB processes on the other hand. For the last two processes, AS and PB, there is a difference, but it is not statistically significant. For the values of the parameters of wastewater leaving the three systems, results showed that there is a seasonal variation in the average values of the parameters (temperature effect) and that with the exception of orthophosphate, the values recorded are, for the most part, below the values of Algerian discharge standards, WHO standards and FAO standards.