Examinando por Autor "Fernandez Mohedano, Ángel"

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Anaerobic treatment of wastewater from used industrial oil recovery
(SCI, 2012-02-24) García-Mancha, Nuria; Puyol Santos, Daniel; Monsalvo García, Víctor Manuel; Rajhi, Hayfa; Fernandez Mohedano, Ángel; Rodríguez Jiménez, Juan José
BACKGROUND: This work is focused on the anaerobic biodegradation of wastewater from used industrial oils (UIO) recovery using a bench-scale expanded granular sludge bed reactor (EGSB) at room temperature. RESULTS: Biodegradability tests showed that this wastewater can be partially biodegraded under anaerobic conditions at mesophilic temperature. Low concentrations of wastewater caused an incremented specific activity of the acetoclastic and the hydrogenotrophic methanogens. Anaerobic biodegradation at room temperature is feasible at organic loading rates (OLR) lower than 5.5 g COD L−1 d−1. A further increase of the OLR to around 10 g COD L−1 d−1 had a detrimental effect on the system performance, making it necessary to work at mesophilic conditions. CONCLUSION: Anaerobic treatment using an EGSB reactor is a feasible option for treating UIO wastewater. Long-term treatment caused a specialization of the granular sludge, modifying substantially its microbial composition. Methane production was even stimulated by the addition of UIO wastewater at low concentrations. Copyright © 2012 Society of Chemical Industry
Short-term fouling control by cyclic aeration in membrane bioreactors for cosmetic wastewater treatment.
(Elsevier, 2015-12-01) Monsalvo, Victor; Lopez, Jesus; Martín Sómer, Miguel; Fernandez Mohedano, Ángel; Rodriguez, Juan José
Air sparging is extensively used to mitigate membrane fouling in membrane bioreactors (MBRs), which represents an important operation cost in submerged MBR. In this work, the effect of intermittent aeration mode on the membrane fouling has been studied by analysing the influence of the aeration cycle duration in a submerged MBR treating cosmetic wastewater. The long-term filtration at a permeate flux of 8.0 L m−2 h−1 and a constant specific air demand (SAD) of 1.5 m3 m−2 h−1 led to a significant increase in the transmembrane pressure (TMP) after 10 d. The tangential shear showed a limited effect on preventing the deposition of small particles, since carbohydrates and proteins present in the fouling layer were mainly smaller than 1 μm. Flocs showed a low stability under shear stress, which limits the increase in the SAD to avoid undesirable effects over the mixed liquor permeability. The intermittent aeration operation allowed the operation of the MBR under low aeration intensity (low SAD) without compromizing the fouling of the membranes. The use of aeration cycles shorter than 1 min led to an efficient control of fouling, which resulted in a negligible increase in the TMP after 2 h, operating at a permeate flux of 12.0 L m−2 h−1.