Groundwater decontamination

Membrane filtration processes have been successfully applied to the field of environmental engineering for air pollution control,34 potable water purification,22-24 groundwater decontamination,35,36 industrial effluent treatment,37 hazardous leachate treatment,35,36 and site remediation,36 mainly because membrane filtration can remove heavy metals and organics. 

Recently, Wang100 introduced a membrane sequencing batch reactor (membrane-SBR) process for groundwater decontamination, water purification, and industrial effluent treatment. A membrane-SBR is similar to conventional SBR except that membrane filtration is used (instead of sedimentation) for the separation of mixed liquor suspended solids (MLSS) from the mixed liquor. 

Wang, L.K., Wang, P, and Clesceri, N.L., Development of a combined biological aeration and flotation system for groundwater decontamination, Proc. Industrial Waste Conference, Purdue University, West Lafayee, IN, 1993. 

Pump-and-Treat Processes for Groundwater Decontamination 18.8.3.1 AirStripping... 

Perhaps the most efficient but least recognized process for groundwater decontamination is dissolved gas flotation, also known as dissolved air flotation (DAF), in which air is used for the generation of extremely line air bubbles having diameters less than 80 pm. 

DAF is used to remove suspended solids by decreasing their apparent density they then rise and float on the water surface. DAF is also used to remove soluble iron, VOCs, oils, and surface active agents by oxidation, air stripping, and surface adsorption. The flotation technology is becoming one of the most important technologies for groundwater decontamination, industrial effluent treatment, and water purification.58-6170... 

The attraction between the air bubble and contaminants is believed to be primarily a result of particle surface charges and bubble size distribution. The more uniform the distribution of water and microbubbles, the shallower the flotation chamber can be. Generally, the depth of effective flotation chambers is between 0.9 and 2.7 m (3 and 9 ft). Flotation units can be round, square, or rectangular. Gases other than air can be used. The petroleum industry has used nitrogen, with closed vessels, to reduce the possibilities of fire. Ozone can be fed through with air for more efficient reduction of soluble iron, VOCs, and so on.57 Ozone-UV flotation is another alternative for groundwater decontamination. 

Several high-rate air flotation clarifiers (both DAF and dispersed air flotation) with less than 15 min of detention times have been developed for groundwater decontamination, industrial effluent treatment, resources recovery, and water reclamation. Both insoluble and soluble impurities such as... 

A DAF-GAC system involving the use of DAF and GAC has also proved to be equally effective for complete groundwater decontamination for the same influent water mentioned above. 

In summation, both DAF and IAF are good innovative processes for more efficient and more cost-effective groundwater decontamination. 

Wang, L.K. Wang, P. Celesceri, N.L. Groundwater decontamination using sequencing batch processes. Water Treatment 1995, 10 (2), 121-134. 

One of many sequencing batch reactor (SBR) processes developed by Wang, Kurylko, and Wang in 1994 (125) is a physicochemical sequencing batch reactor adsorptive bubble separation (SBR-ABS) process, which can be used for potable water purification, industrial water treatment, wastewater effluent treatment, and groundwater decontamination (126). There are various types of SBR-ABS systems (a) physicochemical SBR flotation, (b) physicochemical SBR fractionation, (c) biological SBR flotation (2,3,4). The physicochemical SBR flotation has been used successfully in full-scale operation in Europe (123). 

In addihon to potable water and wastewater treatments, UV process can also be used for storm runoff treatment, combined sewer overhow (CSO) treatment, swimming pool water disinfechon, and groundwater decontamination. The readers are referred to another book for more informahon on the applications of UV process in the area of environmental protechon. 

Introduce the chemical oxidation process, its applicability, limitations, and performance for site remediation involving both soil cleaning and groundwater decontamination. 

This section introduces the chemical reduction/oxidation process (Redox), its applica-hihty, limitations, and performance for site remediation involving both soil cleaning and groundwater decontamination. Chemical reduction/oxidation (Redox process) chemically converts hazardous contaminants to nonhazardous or less-toxic compounds that are more stable, less mobile, and/or inert. The oxidizing agents most commonly used are ozone, hydrogen peroxide, hypochlorites, chlorine, and chlorine dioxide (50-59). 

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