José M. Benito

Design and construction of a modular pilot plant for the treatment of oil-containing wastewaters☆

A modular pilot size plant involving coagulation/flocculation, centrifugation, ultrafiltration and sorption processes has been designed and constructed. The pilot plant can be used for the treatment of different water-based coolants and oily wastewaters, generated in metalworking processes and steel cold rolling operations. Different treatments are considered depending on the nature of the oily waste emulsion. The main advantage of the plant is its versatility, allowing the combination of several of the aforementioned treatments. It is a feasible waste management alternative with potential savings as a result of a better control of the elimination of oily wastes and water reuse, with the result of environmental and economic benefits.

Ultrafiltration of a Waste Emulsified Cutting Oil using Organic Membranes

The influence of operating conditions on permeate flux was investigated using organic ultrafiltration membranes to treat a synthetic cutting-oil emulsion containing 0.05 to 0.8 wt. % oil. A commercial cutting oil, Alba-Kool, and four organic ultrafiltration membranes, two made of polysulfone (PM10 and PM30) and the other two of regenerated cellulose (YM10 andYM30), with cut-off sizes of 10 000 or 30 000 Dalton, were used.All experiments were performed in a commercially available stirred ultrafiltration cell. Within the range of operating conditions studied, it was found that the highest fluxes wereobtained at the following conditions: crossflow velocity (rotation speed) of 375 rpm, temperature of 40 °C andtransmembrane pressure of 0.1–0.15 MPa. Oil rejections between99 and 99.9% were obtained. Complete membrane regeneration wasachieved with a 2 vol. % aqueous solution of a commercial cleaning agent (Derquim+, Panreac).

Integrated process for the removal of emulsified oils from effluents in the steel industry

Emulsified oils contained in aqueous effluents from cold-rolling mills of the steel industry can be effectively removed via an integrated process consisting of a coagulation/flocculation stage followed by ultrafiltration of the resulting aqueous phase. The effects of CaCl2, NaOH, and lime on the stability of different industrial effluents were studied in the coagulation experiments. The flocculants tested were inorganic prehydrolyzed aluminum salts and quaternary polyamines. Ultrafiltration of the aqueous phase from the coagulation/flocculation stage was carried out in a stirred cell using Amicon PM30 and XM300 organic membranes. Permeate fluxes were measured for industrial effluents to which the indicated coagulants and flocculants had been added. Oil concentrations in the permeate were 75% lower than the limits established by all European Union countries. Complete regeneration of the membrane was accomplished with an aqueous solution of a commercial detergent.

The importance of specification sheets for pressure-driven membrane processes

The design, optimization and integration of pressure-driven membrane process require a vast array of information. Such information is usually given in specification sheets. In the following article Susana Luque, Jose Manuel Benito and Jose Coca of the University of Oviedo, Spain, discuss in detail the development of a preliminary pressure-driven membrane process specification sheet and provide examples of where it can be used.

Drop Size Distribution of O/W Emulsions by Drop Immobilization with Agarose

ABSTRACT A method for the determination of the drop size distribution of oil-in-water (O/W) emulsions is presented. Water-based coolant emulsions used in rolling mill operations were studied. The emulsions were gelled in agarose so that the oil droplets were immobilized and samples of these gels were measured by confocal laser scanning microscopy (CLSM) and image processing. The influence of the addition of CaCl2 as an emulsion destabilizer on the size distributions was also studied. The experimental data obtained were compared to those obtained using photon correlation spectroscopy (PCS).