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Morocco, like other arid and semi-arid countries, faces a growing water shortage, necessitating the exploration of alternative solutions. This study investigates the potential use of untreated urban wastewater for irrigation and environmental impact mitigation, focusing on El Jadida as a case study. Throughout the year 2023, from January to December, a comprehensive characterization of physico-chemical, heavy metal, and biological parameters of this unconventional water source was conducted to account for seasonal variations, particularly between rainy and sunny periods. Samples were collected at the inlet of the El Jadida wastewater pre-treatment plant (WWTP) to assess the city's net pollution levels. Results indicate high values for chemical oxygen demand (COD = 741 mg/L), biological oxygen demand (BOD5 = 344 mg/L), organic load (BOD5/COD ratio = 2.2), and biodegradability, suggesting a strong need for biological treatment. Despite compliance with discharge standards, concentrations of heavy metals such as mercury (Hg), cadmium (Cd), aluminum (Al), manganese (Mn), and fluoride ions (F-) exceed Moroccan irrigation water quality thresholds by 90%, 66.7%, 21.8%, 33.3%, and 86.1%, respectively. Therefore, advanced chemical treatment is highly recommended to mitigate environmental impact and ensure safe reuse for irrigation. The novelty of this study lies in evaluating the suitability of El Jadida's wastewater for irrigation and environmental impact mitigation, underscoring the critical need for effective treatment solutions to enhance water sustainability in Morocco. Future research will focus on optimizing water treatment processes.

Abstract Microbial fuel cells (MFCs) have attracted a great deal of attention as a promising technology for recovering electricity from organic substances by harnessing the metabolic activities of microorganisms. The objective of this study is to assess the efficacy of a LiTa0.5Nb0.5O3/g-C3N4 (LTN/g-C3N4) heterojunction as a photocathode catalyst within a single-chamber microbial fuel cell operating under both light irradiation and dark conditions. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Energy dispersive X-Ray spectroscopy (EDS) were used to conduct a comprehensive analysis of the composite catalyst, revealing its exceptional purity and unique properties. After 120 h of exposure to visible light, the maximal power density of the MFC containing LTN/g-C3N4-modified carbon cloth was determined to be 667.7 mW/m3. The power density achieved with the presence of light was approximately three times greater than the power density obtained without light in the MFC (235.64 mW/m3). In addition, the study determined that the removal efficiencies of chemical oxygen demand (COD) were 88.4% and 66.5% when exposed to light and in the absence of light, respectively. These findings highlight the potential of the non-precious LTN/g-C3N4 photocatalyst as a viable alternative for effective wastewater treatment and power generation in microbial fuel cells with a single chamber configuration.

Wastewater from wastewater treatment plants (WWTPs) often requires further treatment before it can be safely reused. Lime is a common and affordable material used for this purpose, but its production can generate significant environmental impacts. This study developed an eco-friendly and effective lime substitute from eggshell waste for wastewater treatment. First, pre-treated wastewater effluent from WWTP El Jadida, Morocco, was collected and characterized. It was found that COD, BOD5, and TSS values showed non-conformity from Moroccan discharge standards, as well as high concentrations of heavy metals such as cadmium (Cd), zinc (Zn), aluminum (Al), chromium (Cr), manganese (Mn), lead (Pb), silver (Ag), beryllium (Be), copper (Cu) and cobalt (Co). These pollutants represent a potential risk to human health and the environmental ecosystem. To reduce this pollution, the optimal mass of lime powder obtained by thermal treatment of eggshell waste was determined by testing a concentration series of 6, 12, 18, 24, 30, and 36 g/L. The findings confirmed that the addition of the optimal dose of prepared lime (24g/L) resulted in a significant reduction in pollution parameters, with abatement rates of 77% for BOD5, 63% for COD and 66% for TSS, respectively. Furthermore, the eco-friendly lime substitute also showed promise in reducing the colorization rate for dyes by 84% and removing heavy metals through precipitation. However, the generated by-product loaded with toxic pollutants should be encapsulated in eco-materials to ensure safe operation and contribute to a sustainable management strategy for wastewater treatment.

Toxic contamination of agricultural soils by trace metal(oid)s can pose detrimental effects on human health and agroecological systems. In this view, the current research explored total and available metal(oid)s in surface soils and assessed the associated hazards using pollution indices, PMF modeling, PCA, and Montecarlo probabilistic human risk assessment with 10,000 repetitions. The mean concentrations of Cd, Pb, As, Cr, Ni, Cu, Zn, and Fe were 0.89, 24.86, 1.81, 19.10, 25.44, 7.98, 49.12 and 6183.32 mg kg−1 dry weight, respectively. These findings highlighted that the concentration of pollutants exceeded the values measured in the geochemical background. Soil enrichment by heavy metal (oid)s was confirmed by analyzing available fractions using DTPA ,CaCl2 and enrichment factor (EF). Additionally, pollution indicators (Igeo, PLI, and PERI) displayed significant contamination levels, with a higher ecological risk. Matrix Factorization (PMF) receptor and multivariate statistical analysis reflected that anthropogenic activities, particularly landfilling and agricultural practices were the main causes of the contamination. Furthermore, probabilistic and deterministic human risk assessments showed that carcinogenic risks exceeded the threshold values (10−4) set by the USEPA. Consequently, it is crucial to implement continuous monitoring and supervision of landfill sites to prevent additional pollution. These measures should be integrated into the management plans for waste management.

The sewage sludge recycling as an agricultural land resource has received a great deal of attention worldwide. This practice is highly increased because of ever-increasing municipal wastewater production and the awareness of its fertilizing potential as an amendment resources. However, there is concern about land spreading linked mainly to health associated risks due to the presence of diverse pollutants. Thus, sewage spreading management is a key factors the guarantee benefits and avoid risks. The present work aims to investigate the benefits and risks of sewage sludge (SS) application on agricultural land. To this end, physicochemical main parameters and Bacteriological indicators, fecal coliform (FC) and fecal streptococcus (FS), of sewage sludge generated form WWTP of Skhirat, Morocco, were performed during the period 2018-2019. The obtained results of physicochemical parameters reveals high concentration of organic matter in SS which reach 96.3 mg/l, and in nutrients. Indeed, total Kjeldhal nitrogen TKN reach a maximum of 3791 mgN/l, Potassium K+ reach 58.71 mg/l. In addition, the medium content of CF and SF are respectively around 5.40 CFU/ml and 5.85 CFU/ml for SF.and Total Phosphorus PT reach 508.25 mg/l. In addition, concentrations of micronutrients such as Cl-, SO42-, Ca2+, Mg2+, and Na+ were high which is interesting and could benefit for both soils and plant. Furthermore, theses sewage sludge contains high concentration in heavy metals mainly Zinc and Copper which could be a limit of reuse in land spreading. The obtained results were compared to applied standards and directives established within the framework of the agricultural spreading.

This paper aims to assess soil fertility and risk contamination parameters in response to increased amendment rates of sewage sludge application, under semi-arid climatic conditions of Morocco, using two soil textures: soil A (clay-silty) and soil B (sandy-clay) over two years. To this end, sewage sludge and soils treatments physicochemical parameters, heavy metals content, degree of pollution and associated risks were evaluated and compared to controlled soils. The results showed that all studied parameters changed significantly (p Pb > Zn > Ni > Cd > Cr. Nevertheless, their concentrations were below the critical values established by the European Union for the agronomic use of soil. The obtained results of assessed parameters indicating SS degree of pollution and associated risks showed a low to a moderate contamination risks of heavy metals. Accordingly, environmental risks of sewage sludge application will be related to increase of heavy metals mainly in a long-term agricultural reuse. Thus, optimal management of sewage sludge application is recommended to ensure sustainability and benefits at the same time to master the contamination risks.

Microbial fuel cells (MFCs) provide new opportunities for the sustainable production of energy, converting organic matter into electricity through microorganisms. Moreover, MFCs play an important role in remediation of environmental pollutants from wastewater with power generation. This work focuses on the evaluation of ferroelectric perovskite materials as a new class of non-precious photocatalysts for MFC cathode construction. Nanoparticles of BaTiO3 (BT) were prepared and tested in a microbial fuel cell (MFC) as photocathode catalytic components. The catalyst phases were synthesized, identified and characterized by XRD, SEM, UV–Vis absorption spectroscopy, P-E hysteresis and dielectric measurements. The maximum absorption of BT nanoparticles was recorded at 285 nm and the energy gap (Eg) was estimated to be 3.77 eV. Photocatalytic performance of cathodes coated with BaTiO3 was measured in a dark environment and then in the presence of a UV–visible (UV–Vis) light source, using a mixture of dairy industry and domestic wastewater as a feedstock for the MFCs. The performance of the BT cathodic component is strongly dependent on the presence of UV–Vis irradiation. The BT-based cathode functioning under UV–visible light improves the maximum power densities and the open circuit voltage (OCV) of the MFC system. The values increased from 64 mW m−2 to 498 mW m−2 and from 280 mV to 387 mV, respectively, showing that the presence of light effectively improved the photocatalytic activity of this ceramic. Furthermore, the MFCs operating under optimal conditions were able to reduce the chemical oxygen demand load in wastewater by 90% (initial COD = 2500 mg L−1).

MFC is a promising technology that can be used for simultaneous electricity generation and wastewater treatment. Power energy generation of a ferroelectric cathodic ceramic, Li0.95Ta0.76Nb0.19Mg0.15O3 (LTNMg), has been measured in microbial fuel cells, integrating a single chamber fed by industrial wastewater (CODinitial = 471 mg L−1, and pHinitial = 7.24 at T = 27 °C). In this process, the mixed multicomponent oxide material has been prepared and characterized by XRD, PSD, TEM, and UV-Vis spectroscopy. The catalytic activity has been investigated by COD determination, analysis of heavy metals, and polarization measurement. The results show a high COD reduction efficiency, which reaches 95.70% after a working time of 168 h with a maximal power density of 228 mW m−2. In addition, the maximum value of generated voltage in the open-circuit potential (OCP) of this MFC configuration has been increased from 340 mV in the absence of a light source to 470 mV under irradiation, indicating the presence of a promoting photocatalytic effect of LTNMg, which improved the process of the cathodic electron transfer inside the MFC device.

The present work is the first investigation of the electrocatalytic performances of ZrP2O7 as a cathode in a single-chamber Microbial Fuel Cell (MFC) for the conversion of chemical energy from wastewater to bioelectricity. This catalyst was prepared by a coprecipitation method, then characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), ultraviolet–visible–near-infrared spectrophotometry (UV–Vis–NIR), and cyclic voltammetry analyses. The acid–basic characteristics of the surface were probed by using 2-butanol decomposition. The conversion of 2-butanol occurs essentially through the dehydrating reaction, indicating the predominantly acidic character of the solid. The electrochemical test shows that the studied cathode material is electroactive. In addition, the ZrP2O7 in the MFC configuration exhibited high performance in terms of bioelectricity generation, giving a maximum output power density of around 449 mW m−2; moreover, it was active for wastewater treatment, reducing the chemical oxygen demand (COD) charge to 50% after three days of reaction.

The objective of this study was to evaluate different rates of the liquid sewage sludge fertilizer developed by a treatment plant in Skhirat, Rabat, Morocco on improving soil fertility indicators. The results revealed that the application of liquid sludge on the soil increased soil pH from 7.3 to 7.7, electrical conductivity from 227.1 to 416.21 µS.cm−1, and other nutrients such as soil organic matter from 9.0 to 21.4%, Kjeldahl nitrogen (TKN) from 0.1 to 0.7%, and total organic carbon (TOC) from 2.4 to 16.5%; the phosphorus ranged 79.1 to 127.8 mg.kg−1 in a dose-dependent manner in amended soil compared to untreated controls. However, the results also showed increase in heavy metal content in the following order: Zn > Cu > Pb > Ni > Cd, (Zn = 136.69 mg.kg−1, Cu = 69.05 mg.kg−1, Pb = 17.91 mg.kg−1, Ni = 4.73 mg.kg−1, Cd = 0.03 mg.kg−1); nevertheless, we noticed that their concentrations were lower than the critical values established by the European Union for the agronomic use of the soil.

The use of 5-azidomethyl-7-morpholinomethyl-8-hydroxyquinoline (AMH) as a corrosion inhibitor for AISI 321 stainless steel in 5.5 M polluted phosphoric acid was investigated using the hydrogen evolution technique, linear polarization curves, and impedance spectroscopy. Impedance measurements revealed that the dissolution of AISI 321 in 5.5 M polluted phosphoric acid was controlled by an activation mechanism, unchanged even with the addition of AMH at different concentrations. Polarization results showed that the inhibition ability was enhanced with increasing inhibitor concentration. AMH acted as a mixed-type inhibitor by random adsorption on the alloy surface, whatever the nature of the reaction that is taking place. The adsorption of AMH on the AISI 321 surface was also discussed via the Langmuir adsorption isotherm. The influence of elevating the solution temperature on the corrosion inhibition performance was studied. A quantum chemistry study with the DFT method was also conducted, which supplied a logical and exploitable theoretical explanation of the adsorption and the inhibition action of AMH on AISI 321.

The present work investigates the influence of temperature on C38 steel corrosion in a 1 M HCl medium with and without different concentrations of a hydro-alcoholic extract of used coffee grounds (HECG). The potentiodynamic polarization technique and the electrochemical impedance spectroscopy were performed in temperatures ranging from 293.15 to 323.15 K. It was observed that the inhibition efficiency decreased with increased temperature and inhibitor concentration. The HECG adsorption process on C38 steel surface was found to be spontaneous and obeyed to Langmuir isotherm at all studied temperatures. The associated thermodynamic parameters of adsorption led to suggest the occurrence of physical adsorption of the HECG compounds on the C38 steel surface.

Biodiesel is a potential alternative for fossil fuel. However, its large-scale application is held up by the disadvantage of a homogenous process, the scarce availability of raw materials and the production cost, which is higher than for fossil diesel. In this work, biodiesel production was carried out using both refined and used cooking oils. The process was investigated in a batch reactor, in the presence of CaO as a heterogeneous catalyst prepared by the calcination of the natural Waste Grooved Razor Shell (GRS). Characterizations by X-Ray Diffraction (XRD) and Thermal Gravimetric (TG)/Differential Thermal Analysis (DTA) showed that the as-received GRS consists of aragonite, (i.e., CaCO3) as the main component and of water and organic matter in a lower amount. After calcination at 900 °C, CaO was formed as the only crystalline phase. The effects of several experimental parameters in the transesterification reactions were studied, and their impact on the produced biodiesel properties was investigated. The studied variables were the methanol/oil molar ratio, the catalyst weight percentage (with respect to the oil mass), the calcination temperature of the parent GRS and the recycling and regeneration of the catalyst. The physico-chemical and fuel properties, i.e., viscosity, density and acid value of used oils and of the produced biodiesel, were determined by conventional methods (American Society for Testing and Materials (ASTM) methods) and compared with the European standards of biodiesel. The optimal identified conditions were the following: the use of a 15:1 methanol/oil molar ratio and 5 wt% of CaO with respect to the oil mass. After 3 h of reaction at 65 °C, the biodiesel yield was equal to 94% and 99% starting from waste and refined oils, respectively.

Microbial fuel cells (MFCs) are an environmentally friendly technology that can recover electricity directly from several wastes at ambient temperatures. This work explores the use of mineral oil refinery wastewater as feedstock in single-chamber air-cathode MFC devices. A polymer inclusion membrane based on the ionic liquid methyltrioctylammonium chloride, [MTOA+][Cl−], at a concentration of 70% w/w, was used as separator, showing a good efficiency in power production and chemical oxygen demand (COD) removal. The power and the chemical oxygen demand removal reached values of 45 mW/m3 and over 80%, respectively. The evolution of other parameters of the wastewater including nitrites, phosphates and sulphates were also studied. Kjeldahl nitrogen and sulphates were significantly reduced during MFC operation. The results show that mineral oil refinery wastewater can be used as feedstock in air breathing cathode-microbial fuel cells based on polymer ionic liquid inclusion membranes. This configuration could represent a good alternative for wastewater depuration while producing energy during the process.