In the present study, the treatability of olive mill wastewater (OMWW) using an anaerobic fixed bed biofilm reactor packed with granular activated carbon (GAC) and inoculated with non-acclimated biomass was performed in a semi-continuous mode under mesophilic conditions. Three organic loading rates (OLR) varied from 0.94 to 2.81 g COD/(L d) were applied. The results of batch adsorption tests on GAC and the experimental data from PBBR-GAC operation were used to set up a COD mass balance in order to investigate the effect of adsorption on the COD removal during the three anaerobic treatment steps. Despite the slight accumulation of volatile fatty acids (VFAs) during the second and the third steps, between 735 and 1135 mg COD/L (as acetic acid), a stable environment for methanogens was maintained for a period of 104 days. During the three steps, degradation levels were up to 80% of COD and 85% of phenolic compounds. An averaged specific biogas production of 1.77 L_N/d and a methane (CH₄) concentration of about 60%, corresponding to a CH₄ yield of 0.31 L CH_4produced/g COD_depleted, were reached at an OLR of 2.81 g COD/(L d). The results show that the COD mass balance was not closed during the first two steps, while in the third step, it could be around 96%. This finding suggests that the adsorption of organic substances on activated carbon occur just during the two first steps, while at 2.81 g COD/(L d) OLR no adsorption is occurring and the introduced COD becomes completely available for CH₄ production. GRAPHICAL ABSTRACT

This study attempts to assess the contribution of entrainment and true flotation in the overall recovery by the laboratory tests performed on a natural complex sulfide ore, provided by la Compagnie Minière des Guemassa (Morocco), and the effect of two different collectors, Potassium Amyl Xanthate (PAX) and Sodium di-isobutyl di-thiophosphinate (Aerophine 3418A), on the two contributions. Overall recovery and true recovery were fitted to first kinetic model and modified flotation parameters were calculated to measure of flotation separation selectivity of chalcopyrite, galena and sphalerite over gangue and pyrrhotite. To estimate the entrainment, Ross method was the most suitable in the case of complex sulfide ore with high content of pyrrhotite. Trahar method overestimates the effect of entrainment.

This study evaluates volatile extracts (HE1 and HE2) from the lichen Pseudevernia furfuracea as eco-friendly agents to control algal proliferation, specifically targeting the cyanobacterium Microcystis aeruginosa and the green microalga Chlorella sorokiniana. Both extracts exhibited potent anti-microalgal activity against the two species with a minimum inhibitory concentration (MIC) ranging from 375 to 750 µg/mL. Furthermore, both extracts reduced cell density by more than 98% after eight days of treatment. Chlorophyll a and protein levels decreased significantly (>80%) in both species, indicating suppression of pigment synthesis. However, their physiological responses were distinct: M. aeruginosa underwent early acute oxidative stress and severe membrane damage, while C. sorokiniana exhibited delayed oxidative activation and a negative growth rate, suggesting non-lytic metabolic inhibition. An in silico study by molecular docking of the most abundant compounds identified in these volatile extracts, such as terpenoids (abietatriene, δ-cadinene) and a phenolic compound (atraric acid), showed that these compounds interact with vital cellular targets in M. aeruginosa and C. sorokiniana and likely contribute to the effects observed in these two species. Predictive toxicity by applying the ADMET framework confirmed the favorable bioavailability and low acute toxicity of these volatile compounds. Therefore, P. furfuracea volatiles are promising, species-specific, and environmentally safe candidates for mitigating aquatic algal proliferation through targeted oxidative and metabolic interference.