Evaluation of methods for the recovery, chemical and toxicological characterization of trace organics
type: CreativeWork
description: "Organic contaminants are generated in substantial quantities by the activities of man and through natural processes, and are present in natural runoff, industrial wastes, and agricultural discharges; synthetic organic chemicals, many of which are refractory and reach surface and subsurface water, are of particular significance. Earlier studies have generally emphasized the organoleptic and esthetic problems caused by trace organics, although their acute and long-term toxic potential has also been recognized. The overall objective of this investigation was the analytical and toxicological characterization of trace organics recovered concomitantly from Missouri waters of varied character by large-scale solvent extraction (SEM) and carbon adsorption (CAM) methods. The specific objectives included the evaluation of solvent extraction contactors, recovery of trace organics from selected sites, development of a subacute toxicity bioassay procedure, and chemical characterization. Three solvent extraction units, a high speed mixer, perforated column and packed column, were built and evaluated under laboratory and field conditions; the first 2 contactors were reasonably efficient in recovering trace organics and relatively inexpensive to build, and the high speed mixer was selected for the large-scale unit. The modified CAM (high flow) system was composed of 2 parallel banks consisting of either 2 activated carbon filters in series or a pressure sand filter followed by 2 carbon filters. The yield of organics from 3 water sources, a lake and 2 rivers, was generally greater for the solvent chloroform extract (SCE), however, the SEM and CAM possessed different selectivities. Increased turbidity usually caused a decrease in the quantity of extracts obtained by the SEM and CAM, and the CAM recovery was 30 percent higher for a treated water than for the corresponding raw river water. Carbon chloroform (CCE) and carbon alcohol (CAE) extracts previously recovered from a large sprin…
abstract: "Organic contaminants are generated in substantial quantities by the activities of man and through natural processes, and are present in natural runoff, industrial wastes, and agricultural discharges; synthetic organic chemicals, many of which are refractory and reach surface and subsurface water, are of particular significance. Earlier studies have generally emphasized the organoleptic and esthetic problems caused by trace organics, although their acute and long-term toxic potential has also been recognized. The overall objective of this investigation was the analytical and toxicological characterization of trace organics recovered concomitantly from Missouri waters of varied character by large-scale solvent extraction (SEM) and carbon adsorption (CAM) methods. The specific objectives included the evaluation of solvent extraction contactors, recovery of trace organics from selected sites, development of a subacute toxicity bioassay procedure, and chemical characterization. Three solvent extraction units, a high speed mixer, perforated column and packed column, were built and evaluated under laboratory and field conditions; the first 2 contactors were reasonably efficient in recovering trace organics and relatively inexpensive to build, and the high speed mixer was selected for the large-scale unit. The modified CAM (high flow) system was composed of 2 parallel banks consisting of either 2 activated carbon filters in series or a pressure sand filter followed by 2 carbon filters. The yield of organics from 3 water sources, a lake and 2 rivers, was generally greater for the solvent chloroform extract (SCE), however, the SEM and CAM possessed different selectivities. Increased turbidity usually caused a decrease in the quantity of extracts obtained by the SEM and CAM, and the CAM recovery was 30 percent higher for a treated water than for the corresponding raw river water. Carbon chloroform (CCE) and carbon alcohol (CAE) extracts previously recovered from a large sprin…
author: Matthews, James Robert
keywords: Civil and Environmental Engineering
date published: 2016-02-10T08:00:00Z
date modified: 2026-07-24T03:19:30Z
provider: Missouri University of Science and Technology
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Missouri--Rolla