Aeration trench

Marley et al. (1994) reported on the typical field application of a trench. The site consisted of clayey silts with an unconfined, perched aquifer with the water table residing 2 ft below ground surface. The trench used was built in 40-ft segments for a total of 360 ft. The trench measured 1 meter in width, and air was injected at a rate of 0.005 m /s per meter of trench. Volatile VOCs were emitted directly to the atmosphere. Bittner and Hoffman (1996) reported on the use of an aeration curtain at a site in Utah. The subsurface was contaminated with trichloroethylene with concentrations as high as 1,000 Mg/L. Air was injected into the trench 21.7 L/s. Approximately 90% of the initial concentrations were removed within 48 hours of operations, and 99% was removed within 8 days. 

Effluents from paper mills and other industrial plants are often treated in large aerated lagoons or trenches in which a slow biodegradation of the pollutants takes place (see Figure 5.4). Pollutant concentration Cl is usually expressed as an equivalent biochemical oxygen demand (BOD, mg O2/L), and the biodegradation process is expressed in terms of a first-order rate constant (day s ). 

FIGURE 14.16 pH-time profile inside the water droplet near the electrode surface at the center of the droplet and at its outer edge. (Reprinted from Electrochim. Acta, 55, Oltra, R., Malki, B., and Rechou, R, Influence of aeration on the localized trenching on aluminium alloys, 4536, Copyright 2010, with permission from Elsevier.)... 

Lin, B., R. Hu, C. Ye, Y. Li, and C. Lin, A study on the initiation of pitting corrosion in carbon steel in chloride-containing media using scanning electrochemical probes, Electrochimica Acta, 55, 2010, 6542. Oltra, R., B. Malki, and F. Rechou, Infiuence of aeration on the localized trenching on aluminium alloys,... 

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