Nutrient additions

In Situ Bioremediation. In situ bioremediation can be an aerobic or anaerobic process, or a combination of the two. In designing an in situ bioremediation system, one should consider the types of microorganisms available (naturally in place or added), the stmctural and chemical makeup of the soil matrix, types of contaminants, oxygen and nutrient addition and distribution, and temperature. These factors are discussed prior to introducing the individual techniques for in situ bioremediation. 

R. N. Miller, "A Field-Scale Investigation of Enhanced Petroleum Hydrocarbon Biodegradation ia the Vadose Zone Combining Soil Venting as an Oxygen Source with Moisture and Nutrient Addition," doctoral dissertation submitted to the Civil and Environmental Engineering Department,... 

While the construction cost for an ET cover is expected to be less than that for a conventional cover, uncertainty exists about the costs for O M after construction. Several factors affecting the O M cost include frequency and level of maintenance (e.g., irrigation and nutrient addition), and activities needed to address erosion and biointrusion. In addition, when comparing the costs for ET and conventional covers, it is important to consider the types of components for each cover and their intended function. For example, it would generally not be appropriate to compare the costs for a conventional cover with a gas collection layer to an ET cover with no such layer. Additional information about the costs for specific ET cover systems is provided in project profiles, discussed in Section 25.9. 

The desulfurization process can be carried out either, in a dedicated reactor, or within a simple storage vessel, or during transportation (in pipelines) or intermediate processing vessels. Nutrients addition, pH, and aeration are adjusted as necessary. Multiple stages can be added to the reaction to enhance the sulfur removal process and decrease the reaction time below the probable 300 h required. The produced sulfates are removed by the addition of agents such as alkaline calcium, magnesium, aluminum, barium, and metal compounds such as oxides, hydroxides, and carbonates. 

Currie, R.S., D.C.G. Muir, W.L. Fairchild, M.H. Holoka, and R.E. Hecky. 1998. Influence of nutrient additions on cadmium bioaccumulation by aquatic invertebrates in littoral enclosures. Environ. Toxicol. Chem. 17 2435-2443. 

Pfaender, F.K. and Alexander, M. Effect of nutrient additions on the apparent cometabolism of DDT, J. Agric. Food Chem., 21(3) 397-399, 1973. 

Several different strategies to overcome nutrient depletion have been used, such as extra nutrient addition to the culture medium prior to infection [68] and partial to complete medium refeeding prior to infection [17]. 

The technology cannot be used to treat nonvolatile compounds, lubrication oils, and heavy end products from petroleum processing except when the technology is configured for bioventing with air injection and nutrient addition. 

Culture medium is typically prepared by addition of the base powder or liquid concentrate mixtures to appropriate grade water. These base media mixtures usually contain amino acids, vitamins, cell membrane precursors, antioxidants, and growth factors, to mention some major categories of nutrients. Additional components, such as proteins or lipids, may need to be added separately since they are usually not compatible in powder blends. 

With ex situ treatment of contaminated soils, a controlled environment for soil treatment can be maintained- With mixing, nutrient addition, aeration, and other environmental controls, mass transfer rates that typically limit in situ bioremediation can be greatly increased. Of course, the disadvantages of ex situ bioremediation are the costs of soil excavation and reactor operation. Thus, ex situ bioremediation is favored by localized, shallow soil contamination. 

American Medical Association. 1982. The nutritive quality of processed foods General policies for nutrient additions. Nutr. Rev. 40, 93-96. 

Aside from adding defined compounds, experimental additions of natural DOM mixtures suspected to vary in lability have helped test ideas about the contribution of various DOM sources to aquatic ecosystems. In a nice example using manipulation of natural DOM sources, Battin et al. (1999) used flowthrough microcosms to measure the relative uptake rates of allochthonous and autochthonous DOM by stream sediments. They documented greater than fivefold differences or more in uptake and respiration, depending on whether the DOM was extracted from soil or periphyton. Moreover, they were able to show, via transplant experiments, several cases where prior exposure to a particular source of DOM increased the ability of that community to metabolize the DOM supplied. There appears to be some preadaptation of microbial catabolic capacity when these stream biofilms were re-exposed to a familiar type of DOM. Similarly, the response of heterotrophic bacteria to carbon or nutrient addition was greatest when the source community was particularly active (Foreman et al., 1998). Kaplan et al. (1996) showed that fixed film bioreactors, colonized on one water source, were unable to rapidly metabolize DOC in water from another source. 

Cheng et al. (2006) incubated for four months black C and black C-soil mixtures at 30 °C and 70 °C, with and without microbial inoculation, nutrient addition, or manure amendment. Incubation caused a decrease in pH from 5.4 to 5.2 and 3.4, as well as an increase in cation exchange capacity by 53% and 538%, respectively. Surface formation of carboxylic functional groups was the reason for the enhanced CEC during oxidation. 

Miller WM, Wilke CR, Blanch ITW (1989), Transient response of hybridoma cells to nutrient additions in continuous culture I. Glucose pulse and step changes, Biotechnol. Bioeng. 33 487-499. 

This type of bioreactor consists of two main parts a disposable sterile bag made of flexible plastic, in which cells are cultivated, and a moving platform that supports and shakes the plastic bag. A hydrophobic filter attached to the bag allows the supply of gases, and small tubing allows culture sampling, as well as nutrient addition and product harvesting. 

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