Engineering enhancement of slow sand filtration has been an enigma in large part because the mechanisms responsible for particle removal have not been well characterized. The presumed role of biological processes in the filter ripening process nearly precluded the possibility of enhancing filter performance since interventions to enhance biological activity would have required decreasing the qu...

Laboratory column studies were conducted at the Utah Water Research Laboratory, Logan, Utah, to evaluate reovirus removal from drinking water supplies by slow-rate sand filtration (SSF). Columns, constructed to simulate a full-scale SSF field operation, were inoculated with reovirus at ca. 1,000-times-greater concentrations than those typically found in domestic sewage. Reovirus removal and ina...

In this paper, results of new intermittent sand filter design was presented. Drawer Compacted Sand Filter DCSF is a modified design for sand filter, in which sand layer is broken down into several layers (10 cm each) and placed in a movable drawers separated by 5 cm space each. Lab-scale DCSF was designed and operated in Surrey University's lab for 49 days and fed by synthetic greywater. 30 cm ...

While sand filters are widely used to treat drinking water, the role of sand filter associated microorganisms in water purification has not been extensively studied. In the current investigation, we integrated molecular (based on metagenomic) and physicochemical analyses to elucidate microbial community composition and function in a common sand filter used to treat groundwater for potable consu...

Background & Aims of the Study: Spent filter backwash water (SFBW) consists of 1-5% of the total treated water typically and it has a high turbidity. Because of the scarcity of water resources and in order to prevent the environmental contamination, effluent treatment of rapid sand filter backwashing is unavoidable. One of the new technologies for removal of turbidity from the ...

In this study, we investigated the establishment of natural bacterial degraders in a sand filter treating groundwater contaminated with the phenoxypropionate herbicides (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and (RS)-2-(2,4-dichlorophenoxy)propanoic acid (DCPP) and the associated impurity/catabolite 4-chlorophenoxypropanoic acid (4-CPP). A pilot facility was set up in a contamin...

Prechlorination is used as an initial step in water purification for public supply. One of the drawbacks of the prechlorination is the reaction between natural organic matters with chlorine forming trihalmethanes. This study aims at evaluating the performance of granular activated carbon (GAC) with sand as a dual filtering media with different depths on removal of trihalomethanes (THMs) for imp...

background: increased impervious surfaces in urban areas not only increase runoff volume and peak flow, but also worsen urban storm water pollution. the polluted runoff has many adverse impacts on human life and environment. the purpose of this study was to investigate and compare the efficiency of sand columns coated with nanoparticles of iron oxide in the presence and absence of a magnetic fi...

The removal of contaminants in slow sand filters occurs mainly in the colmation layer or schmutzdecke a biologically active layer consisting of algae, bacteria, diatoms and zooplankton. A ripening period of 6 8 weeks is required for this layer to form, during which time filter performance is sub-optimal. In the current study, an environmental scanning electron microscope was used to visualise t...

Viral contamination of public waters is a leading health concern around the world, including in Minnesota where cold climate, abundant onsite systems on poor or thin soils, and abundant surface water resources present a significant risk of wastewater pathogens reaching sensitive water sources. Three alternative onsite treatment systems, a sand filter, peat filter and subsurface-flow constructed...