it introduced an innovative bioengineering method of consolidating incompact sand by urea-hydrolysis producing calcite cementation under the inducement of urease producing microbe. in the paper it discussed the effects of cementation methods and time on porosity and mechanical properties of microbe-inspired cementing sand columns. method a adopted reaction fluid gravitational permeating and ext...

heavy metals due to their non biodegradability properties and can accumulate in living tissues, thus becoming concentrated throughout the food chain and can be readily absorbed into the human body. among them manganese was examined in this study as a pollutant. the aim of this study is the manganese removal from aqueous solution using a windy sand fixed bed column of sistan plain. flow rate, in...

The study has investigated the feasibility of using siderite-coated quartz sand and/or hematite-coated quartz sand columns for removing As from water. Arsenic-spiked tap water and synthetic As solution with As concentrations from 200 to 500 mug/L were used for the experiments. Since three coating methods employed to prepare siderite-coated quartz sand and hematite-coated quartz sand had no sign...

In this study the concept of biofilm accumulation in the sand column was promoted to assess the changes in hydraulic conductivity and concentration of organic contaminants of the synthetic leachate. Four different combinations of column study were carried out using synthetic leachate as a substrate solution. Mixed and stratified mode of experiments with two different sizes (0.3 mm and 0.6 mm) o...

A series of column experiments was undertaken to explore the influence of colloid input concentration (2, 1, 0.5, and 0.25 times a reference concentration), colloid size (negatively charged 3.2 and 1.0 microm carboxyl latex), and sand grain size (360, 240, and 150 microm quartz sands) on transport and deposition. A similar mass of stable mono-dispersed colloids was added to each column. For a g...

The aim of this study is to evaluate the biodegradation performance of phenol in a fixed biofilm developed in sand soil media. The parameters which had been studied and may influence the biodegradation were: a) the grain size of sand, b) the rate of flow, and c) the initial phenol loading. Laboratory scale of two columns with inner diameter of 5 cm was used. The first column was packed with fin...

The effect of soil moisture on the distribution of Steinernema riobrave in a sand column was determined. Larvae of Pectinophora gossypiella were used to detect S. riobrave infective juveniles (IJ) in each 2.5-cm section of 30-cm-long soil columns. Soil moisture was determined for each section and related to the numbers of nematodes recovered from infected insect baits. Infective juveniles of S....

The effects of porous medium heterogeneity on methane hydrate formation, water flow through the heterogeneous hydrate-bearing sand, and hydrate dissociation were observed in an experiment using a heterogeneous sand column with prescribed heterogeneities. X-ray computed tomography (CT) was used to monitor saturation changes in water, gas, and hydrate during hydrate formation, water flow, and hyd...