A full-scale demonstration of an integrated fixed-film activated sludge (IFFAS) process with floating carriers has been conducted in Ontario, Canada, since August 2003. In this study, data collected on-site from July 2005 to December 2006 are analyzed and compared with the performance of a conventional activated sludge train operated in parallel. Both trains received similar loadings and mainta...

Comparison study is required to evaluate the treatment efficiency of three alternative secondary treatment processes. These Processes are Integrated Fixed-film Activated Sludge (IFAS), Membrane Bioreactor (MBR) and Conventional Activated Sludge (AS). This study is required for a new wastewater treatment plant. The characteristics of the influent domestic wastewater for the proposed plant were m...

Background & Aims of the Study: High concentration of nitrogen compounds in water and wastewater can be caused various problems and diseases such as methhemoglobinemia and eutrophication. The aim of this study was investigated nitrification and denitrification from wastewater using integrated fixed film activated sludge (IFAS) includes powder activated carbon. Materias and Methods: The labo...

By combining the wavefronts produced by two high-aperture lenses, two-photon 4Pi-confocal microscopy allows three-dimensional imaging of transparent biological specimens with axial resolution in the 100-140-nm range. We reveal the imaging properties of a two-photon 4Pi-confocal microscope as applied to a fixed cell. We demonstrate that a fast, linear point deconvolution suffices to achieve axia...

More stringent effluent criteria with regard to nitrogen call for improved nutrient removal techniques in wastewater treatment plants (WWTPs). Besides optimisation of the liquid treatment train of the plants, over the last years, attention has increasinly centred on the problem of return flows from sludge treatment. Depending on sludge handling and treatment, some 15 to 25 % of the influent nit...

Prior to the initiation of DNA replication, chromosomes must establish a biochemical mark that permits the recruitment in S phase of the DNA replication machinery that copies DNA. The process of chromosome replication in eukaryotes also must be coordinated with segregation of the duplicated chromosomes to daughter cells during mitosis. Protein complexes that utilize ATP coordinate events at ori...

This paper describes representations of biological processes based on Rewriting Logic and Petri net formalisms and mappings between these representations used in the Pathway Logic Assistant. The mappings are shown to preserve properties of interest. In addition a relevant subnet transformation is defined, that specializes a Petri net model to a specific query to reduce the number of transitions...

Probability and indeterminism have always been core philosophical themes. Biology provides an interesting case study to explore these themes. First, biology is teeming with probabilities, and so a crucial question in the foundations of biology is how to understand these probabilities. Second, philosophers want to know whether the processes investigated by one of the major sciences – biology – a...

Plants and insects use slender conical structures to transport collect small droplets, which are propelled along the due capillary action. These droplets can deposit a fluid film during their motion, but despite its importance many biological systems industrial applications properties of deposited unknown. We characterise deposition by developing an asymptotic analysis together with experimenta...