Sand filter

About: Sand filter is a research topic. Over the lifetime, 2280 publications have been published within this topic receiving 19832 citations. The topic is also known as: Sand filter.

Arsenic Removal from Drinking Water using Iron Oxide-Coated Sand

Abstract: This article describes experiments in which iron oxide-coated sand(IOCS) was used to study the removal of both As(V) and As(III) to a level less than 5 μg L-1 in drinking water. Iron oxide-coated sand 2 (IOCS-2) prepared through high temperature coating process was used in batch and column studies to assess the effectiveness and suitability. The isotherm study results showed that the observed data fitted well with the Langmuir model, and the adsorption maximum for IOCS-2 at pH 7.6 was estimated to be 42.6 and 41.1 μg As g-1 IOCS-2 for As(V) and As(III), respectively. In the fixed bed column tests to study arsenic removal from the tap water, good performance ofIOCS-2 was observed in respect of bed volumes achieved and arsenic removal capacity. Five cycles of column tests were conducted to evaluate the performance of IOCS-2, and arsenic wassuccessfully recovered from the media through regeneration and backwash operations. High bed volumes (860 to 1403) up to a breakthrough concentration of 5 μg L-1 were achieved inthe column studies with tap water, and the bed volumes achievedin the studies with natural water (containing arsenic) were 1520.The results of both the batch and column studies showed that ironoxide-coated sand filtration could be effectively used to achieveless than 5 μg L-1 As in drinking water.

Effect of bacterial extracellular polymers on the saturated hydraulic conductivity of sand columns

Abstract: Columns were packed with clean quartz sand, sterilized, and inoculated with different strains of bacteria, which multiplied within the sand at the expense of a continuous supply of fresh nutrient medium. The saturated hydraulic conductivity (HCsat) of the sand was monitored over time. Among the four bacterial strains tested, one formed a capsule, one produced slime layers, and two did not produce any detectable exopolymers. The last two strains were nonmucoid variants of the first two. Only one strain, the slime producer, had a large impact on the HCsat. The production of exopolymers had no effect on either cell multiplication within or movement through the sand columns. Therefore, the HCsat reduction observed with the slime producer was tentatively attributed to the obstruction of flow channels with slime. Compared with the results with Arthrobacter sp. strain AK19 used in a previous study, there was a 100-fold increase in detachment from the solid substratum and movement through the sand of the strains used in this study. All strains induced severe clogging when they colonized the inlet chamber of the columns. Under these conditions, the inlet end was covered by a confluent mat with an extremely low HCsat.