M. Sancho

Static cleaning tests as the first step to optimize RO membranes cleaning procedure

AbstractMembrane fouling is an intrinsic problem of membrane technology which affects process performance and causes a substantial rise of the operating costs. This becomes central in seawater desalination processes. This study is focused on applying a membrane chemical cleaning protocol to obtain the most adequate cleaning conditions to recover the permselective properties of an irreversibly fouled reverse osmosis membrane from a seawater desalination plant. The research was carried out in three steps: fouling characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy and elemental analysis; static cleaning tests; and characterization of the membrane surface after the cleaning step. The cleaning process was performed in a static way as a preliminary step. Five of the most widely used cleaning agents were tested (NaOH, citric acid, HCl, sodium dodecyl sulfate [SD...

Alternatives to the use of synthetic organic coagulant aids in drinking water treatment: improvements in the application of the crude extract of Moringa oleifera seed

AbstractDrinking water treatment is a process based on multiple stages that has a main objective to provide water safe enough to be consumed by humans. Coagulation–flocculation is used to remove colloidal and suspended solids. This process improves the performance of subsequent stages (as sedimentation or filtration) as well as the water quality with a desired end-use. For many years, inorganic and organic synthetic polyelectrolytes have been used in coagulation–flocculation processes. However, its use has been deeply studied recently to determine the potential impact of residual concentration of these substances on human health and the environment. Strict regulations limit the concentration of free residual monomer after the addition of polyacrylamide (PAM) in drinking water treatment and study the effect of interaction of the residues with disinfection products. Therefore, in the last years there has been a resurgence of interest to use natural materials with the same performance that synthetic, but wit...

Recovery of solved salts of the liquid effluents from the manufacture of cured hams: preliminary study

Abstract Liquid effluents generated in the food industry can be treated by several separation processes to recover some components for possible reuse and/or valorization. This is done to further concentrate the volume of final waste to be managed. One of the industrial process in which this problem arises is the manufacturing of cured hams. In this process, hams are subjected to various steps including the addition of salt and subsequent desalting and washing with water, before the start of curing itself. This process generates a liquid effluent characterized by a high content of solved salts (mainly NaCl) and a variable amount of organic matter. Generally, this liquid effluent is dumped without being treated, causing environmental problems. The aim of this work is to find a proper treatment of the liquid effluent from the curing of hams, with the main objective of recovering the solved salts, as well as to minimize the liquid waste volume to manage. Some of the treatment techniques that could be applied ...

Análisis de la calidad de los informes de prácticas de laboratorio en Ingeniería Química: comparación del trabajo presencial con el no presencial

Parte de los resultados publicados en este trabajo pertenecen al PIME “Integracion del Aprendizaje Orientado a Proyectos en una asignatura experimental del Grado de Ingenieria Quimica” (referencia B14) del curso 2016-17, financiado por el Vicerrectorado de Estudios, Calidad y Acreditacion de la Universitat Politecnica de Valencia.

Optimization of chemical cleaning of a reverse osmosis membrane from a desalination plant by means of two-step static tests

AbstractResearch in cleaning procedures of reverse osmosis membranes used in seawater desalination to minimize costs and achieve high efficiency is necessary. Multi-step cleaning can represent a useful tool, since the cleaning efficiency can be improved by means of utilization of different chemicals with complementary cleaning mechanisms. The objective of this work was the optimization of a two-step cleaning procedure to recover the membrane properties and reduce power costs. Spent Hydranautics SWC3 membranes (USA) were supplied by a desalination plant. Cleaning tests were performed in three stages: one-step static cleaning, two-step static cleaning and characterization of the membrane surface after the cleaning process. Four cleaning agents at two different concentrations were used. All possible combinations of them were considered, including sequence effect. After the cleaning process, membrane surface was characterized by field emission scanning electron microscopy coupled with energy dispersive X-ray ...

Study of the relation between kinematic viscosity and SDI in polyethylene glycol solutions for predicting membrane fouling: preliminary test

AbstractNowadays, membrane technology plays an essential role in water treatment as a method of producing good-quality water. Its success is due to its ease of implementation, high efficiency and low cost. However, fouling of the active layer of the membranes is one of the main problems of this technology because it affects the operation conditions of the process, requires maintenance and limits the useful lifetime of membranes. Several parameters have been developed for the prediction of fouling being the most used Silt Density Index (SDI). However, it has some limitations that have prompted the search for alternative parameters such as Modified Fouling Index, Modified Fouling Index-UF, Mini Plugging Factor Index and Unified Membrane Fouling Index, among others. In this work, a prediction methodology of colloidal fouling is studied by means of a direct, simple and immediate measure of the combination of kinematic viscosity and SDI. To perform the tests, synthetic solutions of polyethylene glycol at a con...

Cleaning of ultrafiltration membranes after the treatment of surface water: static–dynamic test

Abstract Access to safe drinkable water is a basic human right and an international development goal. AQUAPOT international project, created by Chemical and Nuclear Engineering Department of the Polytechnic University of Valencia, has been focused on research and development of low-cost and effective water treatment technologies based on membrane technology able to be used in developing countries. After several years of intensive laboratory and field research, Aquapot’s ultrafiltration (UF) plants have been settled in different locations of Ecuador (province of Azuay) and Mozambique (province of Maputo). At present, most of the installed plants work successfully, producing drinking water suitable for human consumption and even for industrial use. However, installation of the designed UF-drinking water treatment facilities has shown that cleaning standard protocol of ultrafiltration membranes is not effective. This fact could affect microbiological quality and volume of the pure water produced and also lif...