Wastewater produced at ready-mixed concrete plants from the cleaning of the concrete truck's drum has recently been banned from direct disposal to ground or surface waters. Recent environmental regulations require readymixed concrete plants to manage and contain wastewater by the use of a reclamation system until it is environmentally acceptable for discharge. The objective of this study was to investigate water quality standards in Florida and the possibility of reusing concrete wastewater as aggregate irrigation and/or batch mixing water in the production of fresh concrete. The results indicate that wastewater used in this study, which did not meet the Florida Department of Transportation (FDOT) water quality specifications but did comply with the water quality standards of AASHTO M 157, had no detrimental effects on concrete properties. Based on the data produced during this project, it is recommended that the FDOT water quality specification be supplemented to address the use of wastewater as aggregate irrigation and/or batch mixing water in the production of fresh concrete.

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An intensive laboratory investigation was undertaken in order to establish the feasibility and strategy for treating soil contaminated with oil at a refinery site.

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S u m m a r yThe sources of dark smoke and particulate elemental carbon (PEC)

This paper describes the laboratory development of a microbial treatment for soil contaminated with oil hydrocarbon residues at a disused refinery site and the application of this technology in a pilot scale treatment bed in the field.

Wastewater contains significant sources of pollutants and contaminants. often the failure of a pipe, inadequate sealing or corrupt pipe-connections cause the loss of raw sewage, which percolates into the nearby soil. As a consequence, a colmation layer in conjunction with soil clogging is developing, which regulates the exfiltration rate. Recently, literature has emerged that offers findings about the effects of wastewater surfactants on the change of physical properties of the soil. A survey of published literature in this field provides information highlighting the influential mechanisms of surfactants in soil clogging through physical, chemical and biological processes. Therefore, to provide a comprehensive approach, this review describes the adsorption mechanisms of surfactants on organic and inorganic particles, at gas-bubbles and at biomass. We also provided our own input to the description of the adsorption of surfactants at fluid/fluid and fluid/solid interfaces in porous media associated with the clogging process.