Infiltration galleries

Any variety of configurations of injection wells, horizontal wells, trenches, infiltration galleries, aboveground sprayers or leach fields, and extraction wells, open ditches, or subsurface collection... 

May be difficult to implement in low-permeability aquifers Reinjection wells or infiltration galleries may require permits or may be prohibited Biodegradation pathways may be site-specific, potentially requiring pilot testing or treatability studies A relatively large amount of oxidant may be needed for treatment of large contaminant mass... 

Injection wells and/or infiltration galleries may become plugged by microbial growth or mineral precipitation. 

Reinjection wells or infiltration galleries may require permits or may be prohibited. Some states require permits for air injection. 

Extraction wells are usually necessary to maintain hydraulic control of the plume and to ensure that the plume does not migrate into clean areas or accelerate migration toward sensitive receptors. Placement of extraction wells is especially important with systems that use nutrient injection wells or infiltration galleries. These sources of fluids can alter natural groundwater flow patterns, which may cause contaminant migration in an unintended direction or rate. If the natural groundwater system has a sufficient concentration of electron acceptors and nutrients, to achieve remediation at an acceptable rate, it may not be necessary to add any additional materials. 

Injection wells or infiltration galleries should be located to provide distribution of the electron acceptor and nutrients throughout the area targeted for cleanup. The impacts on water table gradients caused by injection well... 

In its basic form, bioremediation of the vadose zone involves introduction of nutrients and electron acceptors necessary to stimulate the indigenous bacteria and provide for removal of waste products generated by the reactions. This sometimes takes the form of a series of injections of a soup of nutrients and electron acceptors into the vadose zone through wells, or infiltration galleries. Other sites may require pressure fracturing of the soil before the stimulant blend can be injected. 

A NoVOCs system was tested for remediation of PCE in groundwater at a dry cleaning facility in Hutchinson, Kansas, in 1997. The NoVOCs system included a remediation well, an air diffuser, an infiltration gallery, and four monitoring weUs. The field demonstration cost was approximately 95,000 (D188709, p. 28). 

A common procedure is to add the nutrients in solution through injection wells into the saturated zone or through infiltration galleries into the unsaturated or surface-soil zone. Water is recovered from production wells, then amended with nutrients, and recirculated. The concentrations of contaminants and nutrients are often measured on a regular basis by taking samples from wells installed between the points of injection and removal. In some instances, water is not recirculated but, instead, is treated at the surface. 

Figure 7. Relations between the total outflux recorded during the infiltration test (Test 8) and local oufiux rates from fractures outside the perimeter of the infiltration gallery, collected in Pans 8 and 12 (time series data are shown in...

Provision of infiltration gallery / bore holes in close vicinity of disposal structure for collection and monitoring of ground water. 

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