Search

Changes of environmental situation such as pollution of the atmosphere, surface water and ground water quality deterioration require measures to reduce the harmful effects of human activities on the environment. As such, the problem is the inability of some treatment facilities to provide a quality of treatment that meets the requirements of modern environmental standards. This leads to a decrease in water quality and eutrophication of water bodies. The goal of this article is choice of biochemical treatment method of domestic wastewater for the reconstruction of treatment plants that will ensure quality of quality in accordance with the norms of environmental legislation. In this review, we summarized information on the methods of reconstructing treatment facilities in order to facilitate the choice of purification technology during reconstruction. According to a systematic review of the literature, the use of membrane bioreactors (MBR) allows to achieve a high degree of purification. However, membrane fouling remains the most difficult problem in MBR technology. From the review of literature sources it follows that the use of hybrids technologies (activated sludge and biofilm) in the membrane bioreactor provides a membrane fouling reduction. The hybrid systems are able to provide a high degree of cleaning from organic matter, and nutrients, therefore they are one of the best option for reconstructing facilities that have been designed to only remove carbon contaminants. In general, this literature review not only demonstrates the current problems of reconstruction of wastewater treatment plants, and research needs for scientists working in the field of MBR technologies, but it can also provide more useful recommendations for the selection of cleaning technology in the reconstruction of buildings. [ABSTRACT FROM AUTHOR]

The EU's concentration limit for discharge from wastewater treatment plants is 1 or 2 mg P/dm³ for total phosphorus, signifying a P removal of 80% or more, in order to protect the environment, in sensitive areas which are subject to eutrophication. A membrane bioreactor (MBR) can bused for wastewater treatment, transforming it into reusable water when a tertiary treatment such as nanofiltration (NF) is applied. This step produces a concentrated waste stream. Membrane bioreactors (MBR) permeates are a potentially source for phosphorus (P) recovery. High phosphorous levels in water effluents must be low to avoid eutrophication. An integrated MBR - nanofiltration process with recirculation can assure phosphorous recovery. This study presents an overview on the performances of two MBR NF systems with NF concentrate recirculation systems, with and without P recovery. In order to evaluate the performances, a "blank" MBR was used as a reference. The obtained results showed that for both systems with NF concentrate recirculation, the NF permeate has a sufficiently low P level, allowing both discharging and also its reusing, for example as cooling water in power plants or for irrigation purposes. [ABSTRACT FROM AUTHOR]

Spatial database is a database that is optimized to store and query data. In order to process spatial database a set of functions are needed to process spatial data types called geometry or feature. These set of function are designed by spatial database query framework called Open Geospatial Consortium (OGC). In this paper we have designed Open Geospatial Consortium that will process spatial and non-spatial queries. Open Geospatial Consortium will have simple features specification and set of standards for adding spatial functionality to database systems. The main purpose of this framework is to adapt SQL queries and provide the best result among the available techniques of spatial query processing. The experimental result shows that our framework can process spatial and non-spatial queries with optimal cost. The performance of the queries is measured in the terms of Estimated CPU Cost, Estimated Subtree Cost, Estimated Number of Rows, Estimated Rows Size and Cached plan size. [ABSTRACT FROM PUBLISHER]

As all kinds of defendable and detection software protect information system from destroying by malware effectively, malware becomes more and more advanced too. Current malware continues to penetrate into the underlying bottom of computer system. Bootkit is the newest research product. Bootkit has powerful latent property and resists to most detection tools, which is harmful to information security seriously. In order to research how to detect Bootkit, we have to understand its working mechanism. The research history and actuality of Bootkit is introduced firstly. Moreover several important technologies related to Bootkit are described concretely. Further, the booting process of computer system is analyzed particularly. Then the working mechanism of Bootkit is present comprehensively from three categories of Bootkit. At last, we conclude this paper and indicate future work. [ABSTRACT FROM PUBLISHER]