Suchergebnisse

The term "filtration" in the context of the current Russian aggression against Ukraine is attracting international attention and concern. Since Ukraine and Russia use and contextualise the term differently, there is much space for different interpretations of the process and what it means in practice. The following is an attempt to describe and classify the system of "filtration." The article focuses on "filtration facilities" in the Ukrainian territories currently occupied by Russia as well as in Russia itself, where people can be registered, interrogated, detained, and imprisoned.

In drinking water treatment, filtration plays an important role in the multi-barrier approach employed for the removal of pathogens. The presence of suspended solids and other particulate matter in water increases the resistance of most microbes to disinfection. Therefore, high performance in the removal of particles achieved by granular filtration can increase the disinfection efficiency. Although sand is one of the major filter media, alternative media have been developed and used in recent years. In this review, the performance of alternative media is compared with traditional sand/anthracite for drinking water treatment. Advantages in the use of alternative media, especially glass media, have been found, including high filtration performance in removing residual particles and turbidity, minor modification requirements to the existing filtration configuration and slow head loss development. However, before the employment of them in industry, additional tests are recommended. In particular, full scale tests with variations in the operating conditions and analyses of pathogen removal should be performed. Moreover, this paper reviews the filtration processes and operating configurations which provide overall references to those who are studying and working in the field of water technology and treatment. In this paper, legislations/standards of safe drinking water are summarized as they are the driving force of developing new treatment technologies; mathematical modules for predicting the media filtration performance are briefed. Finally, future work on the application of alternative filter media is recommended.

The paper uses a simple model to present the effects of viscosity and surface tension on the basic parameters of the biological microparticle filtration process. A single filtration membrane with a uniform transmission structure in 2D space was used for the purposes of this analysis. The filtration system relations are described for the threshold filtration force, maximum and minimum height of the filtered liquid to guarantee stable filtration in a gravity field, and the duration of the process and forces affecting the microparticles during filtration. Based on these relations, the summary shows sample calculations for the base model of negative filtration of biological particles. Keywords: microparticle filtration, filtration screens, biological particle filtration, filtration membranes, sedimentation, kinematic viscosity, dynamic viscosity, liquid surface tension

Dargestellt werden Probleme der Gründung und Tätigkeit von Gemeinschaftsunternehmen auf dem Gebiet der UdSSR. Zur Zeit gibt es viele Unklarheiten in Bezug auf Gesetzgebung, Höhe des Stammkapitals, Gewinntransfer usw. Als größtes Problem gilt die Rentabilität des Gemeinschaftsunternehmens auf der Devisen-Basis. Dies sei meistens darauf zurückzuführen, daß die Produkte des Gemeinschaftsunternehmens aufgrund ihrer unzureichenden Qualität nicht in die Drittländer exportiert werden können, da sie der Konkurrenz der westlichen Erzeugnisse nicht standhalten. Um dieses Problem lösen zu können, muß die Qualität der Produkte ständig verbessert werden. Dringend notwendig ist auch das Gesetz über den Schutz von ausländischen Investitionen, um das Interesse der westlichen Partner an der Gründung von Gemeinschaftunternehmen zu fördern. (BIOst-Ldg)

AbstractReduction coagulation filtration using ferrous iron (Fe(II)‐RCF), or reduction filtration using stannous tin (Sn(II)‐RF), for the removal of hexavalent chromium (Cr(VI)) from drinking water represent attractive alternatives to ion exchange or reverse osmosis. With a new maximum contaminant level for Cr(VI) anticipated in California, this study sought to expand on previous research by applying Fe(II)‐RCF and Sn(II)‐RF to multiple groundwaters under a variety of reductant dose and reduction time scenarios. Four different granular filter media were also tested for removal of total chromium (Cr(T)) following Cr(VI) reduction to trivalent chromium (Cr(III)). Sodium hypochlorite, instead of aeration, was used to oxidize excess Fe(II) to Fe(III) prior to filtration, with minimal Cr(III) to Cr(VI) reoxidation. Sn(II)‐RF was also able to achieve Cr(T) and Cr(VI) treatment goals without dedicated reduction time prior to filtration. Results of this study were used to develop more up‐to‐date, feasibility‐level, 20‐year annualized cost estimates.