VOC Removal Processes

Eliminate use of open ponds - Open ponds used to cool, settle out solids and store process water can be a significant source of VOC emissions. Wastewater from coke cooling and coke VOC removal is occasionally cooled in open ponds where VOCs easily escape to the atmosphere. In many cases, open ponds can be replaced with closed storage tanks. 

Advanced Soil Technologies (AST) offers the AST thermal desorption system for the treatment of soil contaminated with volatile organic compounds (VOCs). The process heats the soil to remove the targeted contaminants, which are then destroyed in a secondary treatment chamber. The technology has been available commercially. RIMS was unable to contact the vendor. 

The duration of the remediation is dependent on the soil type, water content, and the nature of the contaminants. The HRUBOUT process cannot remove metals from soils. Polychlorinated biphenyls (PCBs) cannot be totally removed. The in situ HRUBOUT process is designed for removing contaminants from the vadose zone, (i.e., the zone between the surface aud the water table). Low permeability lowers system effectiveness and raises remediation costs. Soils with variable permeabilities may cause uneven delivery of air to contaminants. VOC removal rates may be reduced by high organic content in the soil because soil orgauics have a high VOC-sorption capacity. 

In 1996, the Environmental Process Improvement Center (EPIC) estimated the remediation costs for a two-phase extraction process would range from 70 to 160/lb of VOCs removed. EPIC is an alliance between the U.S. Department of Defense s (DOD s) McClellan Air Force Base, the U.S. Environmental Protection Agency (EPA), and the Cahfomia Environmental Protection Agency (Cal-EPA) (D21566H, pp. 1, 3). 

For optimum efficiency, humidity levels, temperature, and pressure should be monitored and controlled during the adsorption. The adsorption process of VOCs removal is exothermic in the most cases, which should be considered as a significant design parameter, since there is a risk of fire in the removal of high loads of organic compounds that exhibit high heats of adsorption. 

VOC removal from wastewater 246 Air stripping process via a polypropylene hollow-fiber module... 

In particular, liquid-liquid extractions, wastewater treatments, gas absorption and stripping, membrane, and osmotic distillation, are the processes more studied. For example, the VOCs removal, the extraction of aroma compounds and metal ions, the concentration of aqueous solutions, the acid-gases removal, the bubble-free oxygenation/ozonation, have been successfully carried out by using membrane contactors [1, 2]. 

In numerous industrial processes, VOCs and/or air streams containing odorous substances, sometimes in very large quantities, are generated by production. These substances must be concentrated if they are to be disposed of economically. Conventional concentration processes are usually limited to a factor of 10 or a maximum of 20. Due to considerably faster adsorption kinetics, compared to commercial granular activated carbon as well as more favourable isotherm trends for low concentrations, commercial activated carbon cloths (ACC) are particularly suitable for VOC removal at low concentrations ranging from several pg/m ... 

Use Removal of pesticides from drinking water and VOCs from process gases. 

Since the fundamental studies of the Russian schools of Dubinin and Kiselev were carried out in the 1960s, the change in the approach of science toward application and concerns about environmental pollutions, directed the focus of scientific research toward studies of the adsorption of VOCs on carbons from the point of view of the feasibility of the removal process. Of course, this feasibility is related to the strength of the interactions, especially important at low concentrations, and the adsorption capacity (for high concentrations). Since that time also more has been done to understand specific interactions with the carbon surfaces, especially those decorated with functional groups containing heteroatoms [62, 63]. 

Despite a significantly lower adsorption capacity of activated carbons for the removal of SOj and NO from flue gases in comparison with the VOC removal capacity, there are many processes in which they (or activated cokes) are applied for purification of industrial fumes [171-174] from coal fired power plants and waste incinerators. Activated coke is a carbonaceous adsorbent manufactured from lignites or hard coals. Typically, the specific surface areas of commercially available activated cokes are relatively low (up to 400 m g" ) and the pore volumes are only up to ca. 0.25 cm g Depending on the material origin and the manufacturing process, either adsorptive or catalytic characteristics may play a dominant role in the removal of contaminants on this adsorbent. The majority of activated cokes is used for the removal of SO and dioxins fiom waste and flue gases. 

A mobile plasma laboratory for VOC removal from the exhaust streams typical for paper mills and wood processing plants (see Table 11 ) has been built at Drexel University (Fig. 11-68, see Gutsol et al., 2005) based on 10 kW wet (spray) pulsed corona discharge. A photograph of the discharge from one of the six windows is presented in Fig. 11-69 all... 

Design an emission control plant for 50,000 scfm of vent gas at 100°F and 25% relative humidity for 99% removal. The plant is located in Dearborn, Michigan, and the paint spray booths operate on a single 12-hour shift per day. Include the necessary start-up controls. The available fuel is natural gas or oil. Calculate the capital and operating cost and the /lb or ton of VOC removed. Compare the three processes and recommend which is most suitable for this application. 

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