Groundwater injection

The groundwater injection rate should be determined by a field testing program. 

System failure for in situ bioremediation efforts is often the result of ineffective transport of nutrients and electron acceptors due to channeling into preferential flow paths, heterogeneities, adsorption, biological utilization, and/or chemical reactions in the soil. Many of these problems can be overcome using electric fields for transport and injection instead of conventional groundwater injection by hydraulic techniques. 

Micro-, ultra-, and nano-filtration can separate smaller particles using media with defined porous sizes (i.e., 10 1—1 pm in microfiltration, 10 2—10 pm in ultrafiltration, and 10 3— 10 2 pm in nanofiltration). Residual colloidal and suspended solids can be removed by microfiltration. Selected salts, most organic compounds, bacteria, protozoan cysts, oocysts and viruses are removed by nanofiltration, so that the treated water will be disinfected. This advanced filtration is used for the treatment of effluents for indirect potable reuse applications such as groundwater injection, water softening, decoloriza-tion, or removal of micropollution. 

Moreover, MTBE has been found in groundwater, lakes and resei voirs used for drinking water, and it has been linked to possible serious disease. The probable occurrence of cancerous tumors in labora-toiyi rats injected with MTBE alerted federal agencies as to its possible health hazards. In 1999, the EPA reversed itself, recommending the phasing out of MTBE as an additive to gasoline. 

Wiesner MR, MC Grant, SR Hutchins (1996) Reduced permeability in groundwater remediation systems role of mobilized colloids and injected chemicals. Environ Sci Technol 30 3184-3191. 

In a simulated spill, groundwater was spiked with BTEX, MTBE, and chloride as marker, and injected into a sandy aquifer (Schirmer and Barker 1998). Whereas the level of BTEX fell, loss of MTBE was much slower, and only ca. 3% remained after 8 years, although the mechanism of its loss was not resolved. 

McCarty PL, MN Goltz, GD Hopkins, ME Dolan, IP Allan, BT Kawakami, TJ Carrothers (1998) Full-scale evaluation of in situ cometabolic degradation of trichloroethylene in groundwater through toluene injection. Environ Sci Technol 32 88-100. 

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

This analytical method determines levels of major oxanilate and sulfonate soil metabolites of acetochlor, alachlor, and metolachlor in groundwater and surface water. The method consists of analysis of environmental samples by direct aqueous injection reversed-phase LC/MS/MS. 

Water samples, received from the respective groundwater trials, are analyzed by direct aqueous injection (DAI) by LC/ESI-MS/MS. A 1-mL volume of the water is pipetted into a 1.8-mL autosampler vial. The internal standard solution is added (200 qL) and mixed. The vials are capped and analyzed by LC/ESI-MS/MS using the selected reaction monitoring (SRM) mode. 

Figure 3. Systematics of radionuclides along the series. The major and minor fluxes to each nuclide can be readily seen from the arrows showm The behavior of each nuclide can be evaluated by considering the surface and groundwater populations individually, or together as the mobile pool. Nuclides in the decay series within the host rock minerals supply atoms at the surface and in the groundwater by recoil during a decay, so that there are greater abundances in the mobile pool of nuchdes progressively along the series, a decay of nuclides at the surface injects atoms back into the minerals as well as into groundwater.

The combination of SVE with air sparging technology. Air sparging involves the injection of air into the saturated zone of contaminated groundwater. The air bubbles enhance the... 

Air sparging systems, involving the injection of air directly into the groundwater... 

Grouted barriers use a variety of fluids injected into a rock or soil mass, which is set in place to reduce water flow and strengthen the formation. Grouted barriers are seldom used for containing groundwater flow in unconsolidated materials around hazardous waste sites because they cost more and have lower permeability than bentonite slurry walls. Nevertheless, they are suited to sealing voids in rock for waste sites remediation. 

There are three common methods for groundwater collection using pumping systems a well point system, a gravity drain system, and in combination with injection wells. 

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