Date of Award

2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Walid Elshorbagy

Second Advisor

Dr. Zein Elabidin Rizk

Third Advisor

Dr. Ali AI-Marzouqi

Abstract

Dubai is one of seven Emirates that form the United Arab Emirates. The Emirate of Dubai is currently undergoing a fast-paced construction boom that involves huge amounts of concrete mixes. Such mixes are usually delivered to the site in ready form. The major environmental issue with ready-mix concrete production around the world is water pollution. The wash water generated from ready-mix concrete trucks is extremely alkaline and contains significant levels of heavy metals. Removal of heavy metals from the wash water is an environmental problem and economic concern. This demonstrates the urgent need for safe, feasible and economical methods for the elimination of heavy metals from the wash water.

The present study aims at characterizing the heavy metals present in the ready-mix concrete wash water with high levels in addition to investigating the most efficient technologies of removing them.

It is concluded from this study that (1) the possible source of potentially toxic heavy metals in the wash water was the cement sample, (2) high levels of Chromium (Cr) and Strontium (Sr) were found in the wash water with concentrations as high as 2.04 mg/L and 12.21 mg/L, respectively, (3) chemical precipitation was the most efficient technique to remove both the Chromium and Strontium from the wash water, (4) Barium Chloride lowered the Chromium to less than 0.03 mg/L while Disodium Hydrogen Phosphate lowered the Strontium to less than 0.2 mg/L. A conceptual design of a small treatment plant for the ready-mix concrete wash water is proposed.

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