A low-cost high-efficiency wastewater treatment system for small communities up to ~500 p.e. is described. The treatment process comprises a septic tank, a secondary facultative waste stabilization pond and an aerated rock filter. For a wastewater flow of 200 litres per p.e. per day and a BOD contribution of 50 g per p.e. per day the expected final effluent quality is ~5 mg BOD, ~5 mg SS and ~4...

There is lack of consensus in the literature regarding the extent of virus-particle associations in waste stabilization ponds (WSPs) and the implications for virus removal. In this study, the associations of F+ coliphage (measured with the double agar layer plaque assay) and human adenovirus (measured via quantitative PCR) with WSP particles of different sizes were analyzed using a cascade filt...

Geographic information systems (GIS) use is presented in the problem of sitting areas for construction of natural systems such as stabilization ponds (SPs) for domestic wastewater treatment. For this purpose, several variables, such as topography, land use, type of geological formation, distance to major rivers or lakes, distance to existing cities and villages, existence of environmentally pro...

The presence of melt ponds on the surface of Arctic sea ice significantly reduces its albedo, inducing a positive feedback leading to sea ice thinning. While the role of melt ponds in enhancing the summer melt of sea ice is well known, their impact on suppressing winter freezing of sea ice has, hitherto, received less attention. Melt ponds freeze by forming an ice lid at the upper surface, whic...

This study presents an approach for obtaining realization sets of parameters for nitrogen removal in a pilot-scale waste stabilization pond (WSP) system. The proposed approach was designed for optimal parameterization, local sensitivity analysis, and global uncertainty analysis of a dynamic simulation model for the WSP by using the R software package Flexible Modeling Environment (R-FME) with t...

The publication in 1984 of Richard Freeman and James Medoff’s What Do Unions Do?, which summarized and synthesized results from their broad-based research program, was a landmark in labor economics and industrial relations. What Do Unions Do? quickly changed the subject matter and approach for scholars studying unions. The models (or descriptions) of unions employed by labor economists were ext...

1Vasoactive Peptide Group, Department of Clinical Research, University of Bern, 3004 Bern, Switzerland 2Centre for Rheumatology and Connective Tissues Diseases, Royal Free Hospital, Pond Street, London NW3 2QG, UK 3Vascular Unit, Academic Department of Surgery, Royal Free Hospital, Pond Street, London NW3 2QG, UK 4Division of Surgery & Interventional Science, University College London, Royal Fr...

background: heavy metals have destructive and irreversible effects on the human, plants and animals. some industries in yazd enter industrial wastewater to municipal wastewater collection system. this can lead to high levels of heavy metals in wastewater and in turn in the wastewater treatment plant effluent.   methods: this study was carried out during four months from december 22, 2009 to may...

T. AHMAD • Department of Mathematics, Faculty of Science, University of Technology Malaysia, 81310 Skudai, Johor, Malaysia. • Electronics Research Group, School of Engineering, Sheffield Hallam University, City Campus, Pond Street, Sheffield S1 1WB, UK M. A. HOSSAIN • Department of Computing, University of Bradford, Bradford BD7 1DP, UK. • Electronics Research Group, School of Engineering, Shef...

Erosion and sedimentation are normal geologic processes which are usually accelerated by irrigating agricultural lands. Of the sediment in irrigation runoff, 70% was removed in a sedimentation pond. Removal efficiency correlated well with flow rate and sediment concentration. Pond design should provide maximum velocity reduction early in pending, allow adequate storage space for the larger part...