Modeling Tool for Air Stripping and Carbon Adsorbers to Remove Trace Organic Contaminants

Abstract

Removal of trace organic contaminants from aqueous solutions by air strippers (AS) and fixed bed carbon adsorper (FBCA) has been studied. A trace organic treatment tool has been developed to capture and adapt the best-known design procedures and to have all regulated trace organics, their physical and chemical properties, and the corresponding maximum concentration limits. Outputs include the selected treatment method and the final design parameters of air stripper or fixed bed carbon adsorber. Running the model shows that water temperature is a very important factor in designing AS and FBA. It also shows that the best air pressure values, in AS, ranged between 150 -200 ATM. And there is a big relation between the column size and the packing material. On the other hand, it shows that FBA diameter has an obvious effect on the needed volume, and the best values ranged between 1.2 -2.5 m.

Application of a packed column air stripper in the removal of volatile organic compounds from wastewater

“…Several studies investigated the influence of operating parameters on the removal efficiency. In general, VOC removal efficiency was found to depend on temperature, air-to-water (A/W) ratio, hydraulic loading rates, packing materials, size, depth and diameter, gas pressure drop, and Henry's constant of the contaminant (Chuang et al 1992, Nirmalakhandan et al 1993, Alam and Hossain 2009, Mourad et al 2012, Abdullahi et al 2013b). …”

“…The performance of an air stripper is affected by physical and chemical properties of the contaminants and the operating parameters (Mourad et al 2012, Abdullahi et al 2013b). The physical and chemical properties of VOCs give an indication of the physical state of the compound and its mobility.…”

“…The packing increases the surface area of the contaminated water that is exposed to air, thereby maximizing the amount of the VOCs moving from the water to the air. The purified water is collected at the bottom of the column, while the VOC-rich air leaves the column at the top (Mead and Leibbert 1998, Beranek 2001, Richardson et al 2002, Mourad et al 2012. A typical packed column air stripper is shown in Figure 4.…”

“…This constant is a primary indicator of a compound's potential for removal by air stripping and it increases with the increase in temperature. The application of air stripping is limited to compounds with Henry's constant values > 100 atmospheres (Richardson et al 2002, Mourad et al 2012. Applying Henry's law, a mass balance of VOCs in and out of Figure 3 will be as follows:…”

“…The types of air stripper include packed column, sieve tray, and diffused aeration (Kutzer et al 1995, Linek et al 1998, Alam and Hossain 2009, El-Behlil and Adma 2012, El-Behlil et al 2012. The applicability of each technology is based on its performance as reported in engineering literatures, vendor information, and professional experience with the equipment (Wang et al 2006, Mourad et al 2012.…”