Knowledge-based system for automatic MBR control.

MBR technology is currently challenging traditional wastewater treatment systems and is increasingly selected for WWTP upgrading. MBR systems typically are constructed on a smaller footprint, and provide superior treated water quality. However, the main drawback of MBR technology is that the permeability of membranes declines during filtration due to membrane fouling, which for a large part causes the high aeration requirements of an MBR to counteract this fouling phenomenon. Due to the complex and still unknown mechanisms of membrane fouling it is neither possible to describe clearly its development by means of a deterministic model, nor to control it with a purely mathematical law. Consequently the majority of MBR applications are controlled in an "open-loop" way i.e. with predefined and fixed air scour and filtration/relaxation or backwashing cycles, and scheduled inline or offline chemical cleaning as a preventive measure, without taking into account the real needs of membrane cleaning based on its filtration performance. However, existing theoretical and empirical knowledge about potential cause-effect relations between a number of factors (influent characteristics, biomass characteristics and operational conditions) and MBR operation can be used to build a knowledge-based decision support system (KB-DSS) for the automatic control of MBRs. This KB-DSS contains a knowledge-based control module, which, based on real time comparison of the current permeability trend with "reference trends", aims at optimizing the operation and energy costs and decreasing fouling rates. In practice the automatic control system proposed regulates the set points of the key operational variables controlled in MBR systems (permeate flux, relaxation and backwash times, backwash flows and times, aeration flow rates, chemical cleaning frequency, waste sludge flow rate and recycle flow rates) and identifies its optimal value. This paper describes the concepts and the 3-level architecture of the knowledge-based DSS and details the knowledge-based control module. Preliminary results of the application of the control module to regulate the air flow rate of an MBR working with variable flux demonstrates the usefulness of this approach.

[RT-PCR for the determinationof the type of influenza virus circulating in the population]. / RT-PCR para la determinación del tipode los virus de la gripecirculantes entre la población. Grupo de Estudio de la Gripe de la Sociedad Española de Quimioterapia.

Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the type of flu virus that was circulating mostly in the population of the Basque Country in the 1999-2000 season. In this time period, 124 nasal and pharyngeal aspirations from persons with flu-like symptoms were analyzed. A parallel analysis was carried out using a conventional culture or a shell-vial in MDCK cell line, and immunofluorescence and multiple RT-PCR for the detection of influenza virus and its A and B types. Of the samples studied, 57 (45.96%) were positive for type A by the culture method and 64 (51. 61%) by RT-PCR of a genomic region that codifies the non-structural proteins NS1 and NS2. We also developed a rapid-detection method in which the transcription and amplification are carried out in a single step, using the same mix of transcription-amplification. Based on the results we can conclude that RT-PCR is a very sensitive method for the detection of the flu virus; we believe that its sensitivity, combined with its rapidity, makes it ideal for the detection of these respiratory viruses and the analysis of strains circulating in the population.

[Detection of syncytial respiratory virus in clinical samples using a RT-PCR technique]. / Detección del virus respiratorio sincitial en muestras clínicas mediante una técnica de RT-PCR.

From November 2000 to May 2001, 208 clinical samples were analyzed for respiratory infection. Parallel to the detection of the syncytial respiratory virus (SRV) by solid phase immunoassay (EIA) and rapid culture in shell-vial or conventional tube, a reverse transcription polymerase chain reaction (RT-PCR) technique was developed. The procedures were complimentary and useful in the diagnosis of respiratory infections due to SRV, both in children and adults.

RT-PCR para la determinación del tipode los virus de la gripecirculantes entre la población / RT-PCR for the determinationof the type of influenza virus circulating in the population

Se ha usado la transcripción inversa-reacción en cadena de la polimerasa (RT-PCR) para determinar el tipo de los virus de la gripe que circularon mayoritariamente entre la población del País Vasco durante la temporada 1999-2000. Durante este tiempo, se analizaron 124 aspirados nasales y faríngeos de personas con síntomas similares a los de la gripe. Las muestras fueron analizadas en paralelo mediante cultivo convencional o shell-vial en línea celular MDCK, e inmunofluorescencia y RT-PCR múltiple para la detección del virus de la gripe y sus tipos A y B. De las muestras estudiadas, 57 (45,96 por ciento) resultaron positivas para el tipo A por cultivo y 64 (51,61 por ciento) mediante la RT-PCR de una región del genoma que codifica las proteínas no estructurales NS1 y NS2. Desarrollamos también un método de detección rápida en el que transcripción y amplificación se llevan a cabo en un único paso, empleando la misma mezcla de transcripción-amplificación. A la vista de los resultados podemos concluir que la RT-PCR es una técnica muy sensible para la detección de los virus de la gripe; esta sensibilidad, combinada con su rapidez, creemos que la hacen idónea para la detección de estos virus respiratorios y el análisis de las cepas circulantes en la población (AU)

Detección del virus respiratorio sincitial en muestras clínicas mediante una técnica de RT-PCR / Detection of syncytial respiratory virus in clinical samples using a RT-PCR technique

Durante el periodo comprendido entre los meses de noviembre de 2000 y mayo de 2001 se analizaron 208 muestras para el estudio de la infección respiratoria. Paralelamente a la detección del virus respiratorio sincitial (VRS) mediante inmunoensayo enzimático en fase sólida (EIA) y cultivo rápido en shell-vial o tubo convencional, se desarrolló una técnica de transcripción inversa y reacción en cadena de la polimerasa (RT-PCR). Ambos procedimientos resultaron complementarios y de utilidad para el diagnóstico de las infecciones respiratorias por VRS, tanto en niños como en adultos (AU)