Subsurface application

Y. Li, I. C. Y. Yang, K. I. Lee, and T. F. Yen. Subsurface application of Alcaligenes eutrophus for plugging of porous media. In E. T. Premuzic and A. Woodhead, editors. Microbial enhancement of oil recovery recent advances Proceedings of the 1992 International Conference on Microbial Enhanced Oil Recovery, volume 39 of Developments in Petroleum Science, pages 65-77. Elsevier Science Ltd, 1993. 

Tannic acid has been reported to inhibit the formation of hydroxyl radical by chelation of Fe2+ [16], Because tannic acid is a plant-derived material, it and other natural polyphenols may be important for subsurface applications of Fenton chemistry. A study of 50 different iron chelators assessed the affect of each chelator on the Fenton process initiated with Fe3+ and hydrogen peroxide [17]. Among the nine classes of chelators tested, results indicated that the chelators ranged from inactive to highly active in terms of hydroxyl radical formation. 

In the foregoing discussion, the assumption is that each phase is transported in its own percolating network by a pressure-driven flow mechanism. This is the generally accepted view of multiphase flow in subsurface applications, and is certainly true at low values of the capillary number Ca = vfi/a). However, blob mobilization is a dominant form of transport in many unit operations in chemical engineering, where the capillary number and Reynolds number are higher. In these cases, specialized correlations for multiphase flow should be used. 

Unsaturated soil to root depth Evaporation Leaching Root Uptake 0 Surface- Subsurface application Washoff Transport Degradation (chemical/biological) Soil Retention Root uptake Transport. ... 

Remediation of Halogenated Fumigant Compounds in the Root Zone by Subsurface Application of Ammonium Thiosulfate... 

Fumigant compounds have high vapor pressures and are transported in soils largely in the gas phase. Without adequate containment, a significant proportion of the applied mass may be volatilized from die soil surface following soil application. For example, laboratory and field research has indicated that 30-60% of the applied 1,3-D is lost following subsurface application to uncovered soil (i,... 

Figure 2. Concentration of (A) propargyl bromide and (B) cis-l,3 D in the soil gas under the center of the bed prior to subsurface application of ATS.

Recent studies in highly erodible loess soil of China s Shaanxi Province confirm the advantages of subsurface application. Nitrogen fertilizer uptakes were just 18% for surface application to com and 25% to wheat, but the rates rose to between 33 and 36% for subsurface placements see Rees, R. M., et al. 1997. The effects of fertilizer placement on nitrogen uptake and yield of wheat and maize in Chinese loess soils. Nutrient Cycling in Agroecosystems 47 81-91. 

Introduction and Commercial Application The reservoir and well behaviour under dynamic conditions are key parameters in determining what fraction of the hydrocarbons initially in place will be produced to surface over the lifetime of the field, at what rates they will be produced, and which unwanted fluids such as water are also produced. This behaviour will therefore dictate the revenue stream which the development will generate through sales of the hydrocarbons. The reservoir and well performance are linked to the surface development plan, and cannot be considered in isolation different subsurface development plans will demand different surface facilities. The prediction of reservoir and well behaviour are therefore crucial components of field development planning, as well as playing a major role in reservoir management during production. 

As a rule, in practice, the surface defects are revealed by the magnetic-powder and capillary methods. However, in the case of nonmagnetic materials the magnetic-powder methods are not applicable and the capillary ones do not detect the subsurface defects or defects filled with the lubricant after the grinding, wire-drawing and so on. 

The major role of TOF-SARS and SARIS is as surface structure analysis teclmiques which are capable of probing the positions of all elements with an accuracy of <0.1 A. They are sensitive to short-range order, i.e. individual interatomic spacings that are <10 A. They provide a direct measure of the interatomic distances in the first and subsurface layers and a measure of surface periodicity in real space. One of its most important applications is the direct determination of hydrogen adsorption sites by recoiling spectrometry [12, 4T ]. Most other surface structure teclmiques do not detect hydrogen, with the possible exception of He atom scattering and vibrational spectroscopy. 

It may turn out that the same drilling technology that is being used to extract nil and gas, and that has been adapted for mining, geothermal, and water supply applications, will someday be equally useful in sequestering CO, in appropriate subsurface geologic formations. 

The hardness of an enamel surface is an important property for such items as enamelled sink units, domestic appliances, washing machine tubs which have to withstand the abrasive action of buttons, etc. On Moh s scale most enamels have a hardness of up to 6 (orthoclase). There are two types of hardness of importance to users of enamel, viz. surface and subsurface. The former is more important for domestic uses when one considers the scratching action of cutlery, pans, etc. whereas subsurface hardness is the prime factor in prolonging the life of enamelled scoops, buckets, etc. in such applications as elevators or conveyors of coal and other minerals. 

The type of hazard — determines the method and rate of application, e.g. by fixed pourers, mobile monitors, portable foam-towers or fixed semi-subsurface systems. 

The movement of air in the subsurface during the application of SVE is caused by the pressure gradient that is applied in the extraction wells. The lower pressure inside the well, generated by a vacuum blower or pump, causes the soil air to move toward the well. Three basic equations are required to describe this airflow the mass balance of soil air, the flow equation due to the pressure gradient, and the Ideal Gas Law. 

Practical experience from the application of SVE at sites contaminated with a single type of contaminant (e.g., trichloroethylene, TCE) indicates that the removal of contaminants follows a trend in two distinct phases. During the initial phase, which covers the period from the project startup to the exhaustion of NAPL in the subsurface, the removal rate is almost linear. The second phase is characterized by a constant decrease in removal rates. 

The in situ bioremediation application at this site included injection of a liquid microbial solution into the subsurface through monitoring and injection wells. This solution includes microbes (Pseudomonas, Bacillus, and Corynebacterium), oxygen, emulsifier, surfactant, and nutrients. Five injections were conducted. Over 11.3 m3 (3000 gallons) was injected from February 1999 to September 2000 into approximately 40 wells and 15 Geoprobe injection points. As of September 2000, MTBE levels decreased by 96% (3310-146 pg/L), while benzene decreased by 83% (2571— 435 pg/L), toluene by 66% (24,330-8300 pg/L), and naphthalene by 84% (5377-853 pg/L) xylene levels increased and were above preoperational level as of September 2000. The system will continue to be operated until all target levels have been met. The total cost for the cleanup of this site is USD63,500.34... 

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