Engineered soil cell

Engineered soil cell of persistent HMW PAHs Need to control abiotic loss microflora... 

Three solid-phase application strategies are considered here (1) landfarming, (2) composting, and (3) engineered soil cells. The benefits and limitations of these processes are summarized comparative to other implementation strategies in Table 5.7. 

The engineered soil cell is a hybrid of the landfarming and the composting processes. Engineered soil cells are constructed, essentially, as aerated compost piles. Such systems offer the best of both processes and are therefore preferred whenever the site-specific application warrants their use. Key factors to consider include (1) ability to excavate and process material, (2) total volume of material to be treated, (3) expected treatment time, and (4) desired cleanup level. 

The commercially available bioremediation process occurs in an engineered land treatment cell or prepared bed. Contaminated soils and sludges are excavated and transported to the treatment ceU (or bed). Nutrients, water, and oxygen (introduced by tilling the soil) are added to the bed to accelerate the treatment process. After bioremediation is complete, the treatment cell is capped and the site is considered suitable for use. 

Xanthamonas campestris strain engineered to bioluminesce (Shaw et al., 1992). The strain was applied to cabbage plants and surrounding soils in a limited field study conducted in 1990. The fate of the organisms was monitored by both CCD-microscopy and plate counts, Recombinant cells were found for up to six weeks, with the CCD and plate counts giving quantitatively similar results. Bioluminescence in this case was no more sensitive than plate counts, and required a precision instrument,... 

A month later, I arrive early at the lab and hurry over to the growth chamber to check on my tiny plants. Hurrah The genetically engineered cells have produced shoots and roots, the result I was anticipating. I carefully transplant the GE seedlings into soil-filled pots. 

Agrobacterium A soil bacterium that can transfer its own genes across the plant cell wall and membrane into the nucleus. The bacterium s DNA integrates into the plant s genome. The use of Agrobacterium allows the introduction of genes from any species to be engineered into crops. 

Commercialization of this approach has been reahzed for the measurement of the bioavailability of heavy metals (Biomet ). This test uses a relevant soil bacterium (Ralstonia metallidurans) that when adequately engineered produces light when a specific heavy metal enters the cell. 

Vails, M., Atrian, S., de Lorenzo, V., and Fernandez, L. A. (2000). Engineering a mouse metallothionein on the cell surface of Ralstonia eutropha CH34 for immobilization of heavy metals in soil. Nat. Biotechnol. 18, 661-665. 

The method described above forms the basis of the standard determination of the one-dimensional consolidation properties of soils for civil engineering purposes16. The diameter of the cell is not specified other than it should be at least 6 mm smaller than the soil samples available for testing, and the depth of the ring is... 

NPAHs are emitted by diesel and internal combustion engines, and their presence indicates traffic as a source. In a variation of ultrasonic extraction, a closed, stainless-steel extraction cell contained soil samples while solvent was circulated through the cell as sonication was applied with a titanium probe in a water bath. The extract was then flushed out of the extraction cell into a collection vial external to the water bath. The extract was concentrated by rotary evaporation and... 

Baligh, M.M., Martin, R.T., Azzouz, A.S., and Morrison, M.J. 1985. The piezo-lateral stress cell. Proceedings of the 11th International Conference on Soil Mechanics and Foundation Engineering, San Francisco, CA. 

FIGURE 8 Liquid waste disposal cells lined with engineered liners (a) compacted clay (soil) liner and (b) geomembrane liner... 

An excel spreadsheet that requires user to enter information about geotechnical site conditions at each cell in the grid system. The information that should be provided by the user includes soil type, soil layer thickness, ground water level and shear wave velocity profile down to the engineering bedrock (Vs > 750 m/s) for each cell. 

---