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In the present study, drinking water treatment sludge (DWTS) was reused as a catalyst in advanced oxidation processes for the removal of methylene blue (MB) from aqueous solutions. After determining their chemical and mineralogical compositions by X-ray Powder Diffraction (XRD), BET surface area, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), Inductively Coupled Plasma (ICP), and FT-IR spectra. DWTS has been used as a heterogeneous photo Fenton-Like catalyst for the oxidation of MB under different parameters, including pH (3-6), H 2 O 2 concentration (9.79-29.37 mM), and dose (1-2.5 g/L). The results showed that within 180 min and under UV light irradiation, more than 86% of MB having a concentration of 50 mg/L were removed using a catalyst loading of 1.5 g/L, a H 2 O 2 dosage of 23.17 mM and a solution pH of 5. The DWTS has a satisfactory stability as the catalyst is stable and have very less iron leaching property.

The intensive human activities extensively contaminated water sources making its treatment a problem of paramount importance, especially with the increasing of global population and water scarcity. The application of natural coagulants has become a promising and environmentally friendly alternative to conventional ones. This study was aimed at evaluating the efficiency of four plant extracts namely Agave americana, Carpobrotus acinaciformis, Austrocylindropuntia subulate, and Senicio anteuphorbium as natural coagulants to remove Microcystis aeruginosa cyanobacterium from water. The effects of pH (4, 5, 6, 7, 8 9, and 10) and coagulant dose (5, 10, 15, 20, 25, and 30 mg/L) on the coagulation efficiency were investigated. Results showed that plant-based extracts exhibited high coagulant abilities significantly contributing to the removal of M. aeruginosa cells up to 80% on a case-by-case basis. The ecotoxicity (Daphnia magna, Aliivibrio fischeri, Raphidocelis subcapitata, and Sorghum saccharatum) was absent or presented very slight acute toxicity up to 12.5 mg/L being S. anteuphorbium the least toxic. PRACTITIONER POINTS: Nature-based plant extracts showed removal rates up to 80%. Lower pH and A. subulate and S. anteuphorbium were the most efficient coagulants Toxicity effects were plant extracts-based and dose function. A. subulate and S. anteuphorbium were the least toxic extracts., (© 2022 The Authors. Water Environment Research published by Wiley Periodicals LLC on behalf of Water Environment Federation.)

The present work investigates the use of Agave americana fibers (AGF) as a precursor for activated carbon (AC) preparation via chemical activation using phosphoric acid (H 3 PO 4 ), and the study of the influence of the preparation conditions on the adsorption capacity of the prepared AC toward Alpacide Yellow (AY). The preparation experiments have been conducted at different impregnation ratios: acid/AGF (20 g/1 g, 30 g/1 g, and 40 g/1 g) with varied impregnation times (2 h, 4 h, and 6 h) and at different carbonization temperatures (200 °C, 400 °C, and 600 °C). The impregnation ratio of 40 g/1 g, the impregnation time of 6 h, and the carbonization temperature of 400 °C were selected as the optimal conditions for the preparation of AC with enhanced properties. Despite its low specific surface area (25 m 2 /g), the prepared AC showed a higher adsorption capacity toward AY (5.71 mg/g) as compared with that of the commercial activated carbon (CC) (5.27 mg/g) which showed a higher specific surface area (825 m 2 /g). This could be due to the existence of pores and functional groups on the surface of AC, as evidenced by the analysis results of FTIR, DSC, and SEM. The adsorption process was found fast and fractal since it followed the kinetic model of the Brouers-Sotolongo fractal (BSf) (R 2 = 0.999), while the mathematical modeling of the adsorption isotherm of AY on the synthesized AC was stochastic since it followed the General Brouers-Sotolongo (GBS) (R 2 = 0.999)., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

In the present study a new combined process, comprising filtration of raw olive mill wastewater (OMWW) on two successive olive stone (OS) filters followed by a coagulation-flocculation, was developed in order to perform an efficient pretreatment of OMWW. The results show that the use of OS filter leads to a higher removal of total suspended solids (TSS) and fatty matter (FM) from the raw OMWW (about 82.5% and 73.8%, respectively) and a depletion of total phenolic compounds (TP) and chemical oxygen demand (COD) (11.3% and 23.2%, respectively). The coagulation-flocculation was then applied to improve the removal of TP and COD from the filtered OMWW. For this purpose, a full-factorial design was used to study the effect of different factors involved in coagulation-flocculation. The studied variables were: pH (5-8), coagulant type (ferric chloride; FC and aluminum sulfate; AS), coagulant concentration (250-1000 mg/L) and flocculant (Anionique polyelectrolyte Superfloc A120 PWG) concentration (1-5 mg/L). The results reveal that the use of 250 mg/L FC and 5 mg/L flocculant at an acid pH (around 5) allows for, respectively, a removal of TP and COD of about 10.8% and 31.3%.