Aquifers systems

Krumme ML, KN Timmis, DF Dwyer (1993) Degradation of trichloroethylene by Pseudomonas cepacia G4 and the constitutive mutant strain G4 52223 PRl in aquifer systems. Appl Environ Microbiol 59 2746-2749. 

Dearlove JLP, Longworth G, Ivanovich M, Kim Jl, Delakowitz B, Zeh P (1991) A study of groundwater colloids and their geochemical interactions with natural radionuclides in Gorleben aquifer systems. Radiochim Acta 52/53 83-89... 

Somayajulu BEK (1994) Uranium isotopes in the Hooghly Estuary, India. Marine Chem 47 291-296 Spechler RM (1994) Saltwater intrasion and the quality of water in the Floridian Aquifer system, northeastern Florida. US Geol Surv Water Resource Invest Rept 92-4174 Sun Y, Torgersen T (1998) Rapid and precise measurement for adsorbed " Ra on sediments. Marine Chem 61 163-171... 

The total investment cost for the aquifer system (wells, submersible pumps, tubing, control equipment, electrical cables, well chambers and heat ex- changers) was approx. 350,000 Euro. The specific investment cost is then roughly 370 Euro/kW. 

Project management Sydkraft Varme Syd AB, Mahno (Olle Goransson). Aquifer system design SWECO VIAK AB, Mahno (Olof Andersson). Surface system design Sycon Energikonsult, Mahno (mats Egard). 

Application of stable hydrogen isotope models to the evaluation of groundwater and geothermal water resources case of the Padurea Craiului limestone aquifers system... 

A half-life of about 40 days was reported for hexachloroethane in an unconfined sand aquifer (Criddle et al. 1986). Laboratory studies with wastewater microflora cultures and aquifer material provided evidence for microbial reduction of hexachloroethane to tetrachloroethylene under aerobic conditions in this aquifer system (Criddle et al. 1986). In anaerobic groundwater, hexachloroethane reduction to pentachloroethane and tetrachloroethylene was found to occur only when the water was not poisoned with mercury chloride (Roberts et al. 1994). Pentachloroethane reduction to tetrachloroethylene occurred at a similar rate in both poisoned and unpoisoned water. From these results, Roberts et al. (1994) suggested that the reduction of hexachloroethane to tetrachloroethylene occurred via pentachloroethane. The first step, the production of pentachloroethane, was microbially mediated, while the production of tetrachloroethylene from pentachloroethane was an abiotic process. 

In view of experience with the groundwater nitrate problem and the possibility of a large unsaturated time-lag in British aquifer systems (especially in the Chalk), it is necessary to address the following questions in the above investigation ... 

More complex arrangements of aquifers, aquiclude, and aquitards, notably in deep sedimentary basins, are systems of interbedded geologic units of variable permeability. These systems are referred to as a multilayered aquifer system. Such systems are considered more of a succession of semiconfined aquifers separated by aquitards. 

Water and hydrocarbons occurring together, in shallow aquifer systems, may be considered immiscible for flow calculation purposes however, each is somewhat soluble in the other. Since groundwater cleanup is the purpose behind restorations, it receives greater attention. Definition of water quality based on samples retrieved from monitoring wells relies heavily upon the concentration of individual chemical components found dissolved in those samples. An understanding of the processes that cause concentration gradients is important for the proper interpretation of analytical results. 

Maguire, T. F., 1988 Transport of a Non-Aqueous Phase Liquid within a Combined Perched and Water Table Aquifer System In Proceedings of the National Water Well Association of Ground Water Scientists and Engineers FOCUS Conference on Eastern Regional Ground Water Issues, September, 1988. 

Pfannkuch, H. O., 1984, Determination of the Contamination Source Strength from Mass Exchange Processes at the Petroleum-Groundwater Interface in Shallow Aquifer Systems In Proceedings of the National Water Well Association and American Petroleum Institute Conference on Petroleum Hydrocarbons and Organic Chemicals in Groundwater — Prevention, Detection and Restoration, November, Houston, TX. 

For biodegradation to occur, everything that bacteria require for growth and reproduction must be available in the microenvironment in the immediate vicinity of the bacterium. The soil-aquifer system must provide water, attachment medium, a source of carbon, gas exchange, electron acceptor compounds, and nutrients. If any of the required items is not available, bacterial functions will be reduced or cease. 

In some undisturbed subsurface systems, an equilibrium is established. Bacteria have acclimated to food sources, water availability, and electron acceptor types. The number and variety of microbial cells are balanced in this system. If the system is aerobic, the microbial activity continues at the rate of oxygen resupply. If the system is anaerobic, the rate of activity cannot exceed the accessibility of alternate electron acceptors. Generally, the subsurface (lower than the plant root zone) is relatively deficient in available carbon and electron acceptors. Under these normal semi-equilibrium conditions, a soil or aquifer system can consume organic materials within a reasonable range. When a chemical release is introduced into a well-established soil system, the system must change to react to this new energy source. The bacterial balance readjusts, in an effort to acclimate to the new carbon source. 

Peterson, M.S., Lion, L.W., and Shoemaker, C.A. Influence ofvapor-phase sorption and dilution on the fate of trichloroethylene in an unsaturated aquifer system. Environ. Sci. TechnoL, 22(5) 571-578, 1988. 

Nadim R, Hoag GE, Liu SL, Carley RJ, Zack P (2000) Detection and remediation of soil and aquifer systems contaminated with petroleum products An overview. J Pet Sci Eng 26 169-178... 

Peterson MS, Lion LW, Shoemaker CA (1988) Influence of vapor phase sorption and diffusion on the fate of trichloroethylene in an unsaturated aquifer system. Environ Sci Technol 22 571-578 Petersen LW, Moldrup P, El-Farhan YH, Jacobsen OH, Yamaguchi Y, Rolston DE (1995) The effect of moisture and soil texture on the adsorption of organic vapors. J Environ Qual 24 752-759 Pignatello JJ (1989) Sorption dynamics of organic compounds in soils and sediments. In Sawhney BL, Brown K (eds) Reactions and movement of organic chemicals in soils. Soil Sci Soc Amer Spec Publ 22 45- 81... 

Zappi, M. White, K. Hwang, H.M. Bajpai, R. Qasim. The fate of hydrogen peroxide as an oxygen source for bioremediation activities within saturated aquifer systems. J. Air. Waste Manag. Assoc. 2000, 50, 1818-1830. 

CESAR was developed to address the problem of locating, characterizing, and removing dense non-aqueous-phase liquids (DNAPLs) from contaminated aquifer systems. The process is particularly suited to remediating groundwater contaminated with chlorinated solvents, such as trichloroethylene (TCE), tetrachloroethene (PCE), trichloroethane (TCE), and carbon tetrachloride (CCE). According to the vendor, CESAR can also be applied to sites contaminated with creosote, polychlorinated biphenyls (PCBs), Freon 113, volatile organic compounds (VOCs),... 

Buckau, G., Artinger, R., Fritz, P., Geyer, S., Kim, J. I. Wolf, M. 2000. Origin and mobility of humic colloids in the Gorleben aquifer system. Applied Geochemistry, 15, 183-191. 

Kim, J. 1., Delakowitz, B., Zeh, P., Klotz, D. Lazik, D. 1994. A column experiment for the study of colloidal radionuclide migration in Gorleben aquifer systems. Radiochimica Acta, 66/67, 165-171. 

Choppin, G. R. 1992. The role of natural organics in radionuclide migration in natural aquifer systems. Radiochimica Acta, 58/59, 113-120. 

One of the approaches in evaluating the permeability of an aquifer system is to perform an aquifer test by pumping a well and observing the water-level decline with time in nearby observation wells. In systems of low permeability, sufficient water for a pumping test is generally prima facie evidence that it is unacceptable as a disposal site. Consequently, a new set of "parlor tricks" is needed to define the permeability of those types of media. 

Latumus F, Lauritsen FR, Gr0n C (2000) Chloroform in a Pristine Aquifer System Toward an Evidence of Biogenic Origin. Wat Resour Res 36 2999... 

---