Groundwater temperature

The rate of microbial activity in the subsurface is a direct function of temperature. Subsurface microbial activity decreases significantly below 10°C and almost ceases below 5°C. Above 45°C, the microbes responsible for degradation of most organic 

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Fig. 2. Changes in mean weekly groundwater temperatures (6.5 m depth) across the...

Fischer, A., Muller, M., and Klasmeier, J. Determination of Henry s law constant for methyl ferf-butyl ether (MTBE) at groundwater temperatures, Chemosphere, 54(6) 689-694, 2004. 

In this case study, the selected phases are pyrite, amorphous FeS, calcite (present in limestones in the roof strata Fig. 5), dolomite (possibly also present in the limestones), siderite (which occurs as nodules in roof-strata mudstones), ankerite (present on coal cleats in the Shilbottle Seam), melanterite and potassium-jarosite (representing the hydroxysulphate minerals see Table 3), amorphous ferric hydroxide (i.e., the ochre commonly observed in these workings, forming by precipitation from ferruginous mine waters), and gypsum (a mineral known to precipitate subaqueously from mine waters with SO4 contents in excess of about 2500 mg/L at ambient groundwater temperatures in this region, and with which most of the mine waters in the district are known to be in equilibrium). In addition, sorption reactions were included in some of the simulations, to contribute to the mole transfer balances for Ca, Na, and Fe. 

The temperature in the core of the Earth—due to the decay of radioactive isotopes—is on the order of 4,000°C, the temperature of the lava of volcanoes is about 1,200°C, and the temperature of thermal springs can reach 350°C. If the groundwater temperature exceeds 150°C, flash steam power plants can be built, and if it is between 100 and 150°C, binary cycle power plants can be operated. 

The temperature difference between the desired temperature of the conditioned space and the actual underground soil or groundwater temperature (Figure 1.24) can be used for direct cooling in the summer and direct... 

In this demonstration plant, the boiler feedwater can be preheated by geothermal heat if available. Depending on the availability and temperature of the geothermal heat in the area, the geothermal plant s design would vary. If the groundwater temperature exceeds 150°C (302°F), a "flash steam" power plant would be used, and if it is between 100 and 150°C (212 and 302°F), a "binary cycle" power plant would be used. 

Local groundwater temperatures are equal to, or several degrees colder than, the average ambient annual temperature. 

Fig. 4.20 Monthly maps of equal groundwater temperature for a well field bordering the Mohawk River (after Winslow et al., 1965). The river temperature changed over an annual cycle from 77 to 32 °F. The aquifer followed these temperature changes, indicating recharge from the river.

Fig. 4.22 Location map of wells near the Mohawk River with annual groundwater temperatures (from Winslow et al., 1965). Using these values, contours of equal annual temperature variation were drawn. The decrease of these contour values indicates water moves from the river into the aquifer, especially through the zone marked A.

Table IX shows the microbial breakdown with time of [5-i4CH3]-aldicarb, aldicarb sulfoxide and aldicarb sulfone to C02 in groundwater samples. Incubation temperatures of 10°C and 20°C were used to approximate the mean and highest annual groundwater temperatures in Central Wisconsin.

Half-lives in the range of 1.5 to 2 years can be expected for EDB in groundwater in various regions of Florida (22°C). In more northern locations of the U.S. half-lives of about 2 to 5 years could be expected since their typical groundwater temperature is less than 15°C (Table II). 

Overall, desirable characteristics of surfactants for soil remediation purposes include effectiveness, biodegradability, low toxicity, good solubility at groundwater temperature, low adsorption to soil, low surface tension, and a low CMC (West and Harwell, 1992 Mulligan, Yong, and Gibbs, 2001 Lee, 2004). 

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