Injection well aeration

The most common applications of air sparging are in-well aeration and injection well aeration. Where air sparging releases a significant quantity of volatile organic chemicals, an SVE system is often installed in the vadose zone to intercept the vapors for aboveground treatment. 

Injection well aeration is the process of introducing air directly into the aquifer through either a vertical well, which has an isolated short well screen at its base, or a horizontal well installed with the perforations below the contaminated zone (Figure 9.5). The goal is to force compressed air outward through the perforations into the... 

In its passage through a water column, a bubble acts as an interface between the liquid and vapour phases, and as such collects surface-active dissolved materials as well as colloidal micelles on its surface. Thus in a well-aerated layer of water, the upper levels will become progressively enriched in-surface-active materials. In the open ocean, an equilibrium undoubtedly exists between the materials carried downward by bubble injection from breaking waves and those carried upward by rising bubbles. In the laboratory, however, this effect will enrich the surface layer with organic materials. 

In-well aeration is the process of injecting air into the lower portion of a dual-screened well with perforations at the bottom and above the water table. As the bubbles rise, they expand, which causes the mixed mass of air and water to have less density. The result is an air-lift pump effect. When the water rises and exits the upper perforations, replacement water enters the bottom of the well. The result is a circulation cycle. Free air does not enter the aquifer, but dissolved air (and oxygen) travels with the circulating water. Figure 9.4 is a schematic diagram of in-well aeration. 

Aerated Mud. In aerated mud drilling operations, the drilling mud is injected with compressed air to lighten the mud. Therefore, at the bottom of the well in the annulus, the bottomhole pressure for an aerated mud will be less than that of the mud without aeration. However, an aerated mud drilling operation will have very significant bottomhole pressure capabilities and can easily be used to control potential production fluid flow into the well annulus. 

In situ oxygen supply requires aeration wells for the injection of oxygen. The criteria are that the aeration well zone must be wide enough to allow the total plume to pass through, and the flow of air must be sufficient to produce a substantial radius of aeration while small enough so as not to create an air barrier to groundwater flow. The required residence time tr for aeration can be calculated from Darcy s law as a function of the groundwater head and hydraulic conductivity ... 

Pumping station Schuwacht of the drinking water company Hydron-ZH is a bank filtration unit with the pumping wells located at a distance of 70 -200 m from the river Rhine near Gouda, The Netherlands. In 1998 and 1999, pumping from filler PP8 was periodically intermpled to inject a volume of treated and aerated groundwater. Water was injected at 30 m /h for 2 days... 

Experimental design - describes the procedure that will be followed including the number of batches, replicates, analysts, instruments, and any additional detail that may not be covered in the method but is critical to the transfer such as sample and standard preparation, number of injections for each as well as how many samples can be injected between standards, dissolution de-aeration procedure, time frame for completing all testing once the samples are received, such as 30 days. 

Ozone is a very strong oxidizer with a high potential of 2.07V. It has a high reactivity and a short stability, and its solubility in water is exceedingly modest. Therefore, it is more practicable to inject ozone as gas into the unsaturated zone of the soil than to try to create a solution with ozone. Transport of dissolved ozone in the soil-water phase is only possible by electro-osmosis, and due to the short lifetimes, only short distances are possible. Ozone is a by-product in many anodic processes, and the amount of its production is directly proportional to the applied current density. The more efficient way to produce ozone uses classical corona discharge ozone generators. Ozone is not the optimal mediator for electro-kinetic remediation, but an alternative or additional method for a remediation concept using aeration techniques. Ozone works as a direct oxidant and as well as a free radical ... 

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