Bottom sediment

Solids materials that are insoluble in hydrocarbon or water can be entrained in the crude. These are called bottom sediments and comprise fine particles of sand, drilling mud, rock such as feldspar and gypsum, metals in the form of minerals or in their free state such as iron, copper, lead, nickel, and vanadium. The latter can come from pipeline erosion, storage tanks, valves and piping systems, etc. whatever comes in contact with the crude oil. 

The water and sediment contents of crude oils is measured according to the standard methods NF M 07-020, ASTM D 96 and D 1796, which determine the volume of water and sediments separated from the crude by centrifuging in the presence of a solvent (toluene) and of a demulsifylng agent Table 8.13 gives the bottom sediment and water content of a few crude oils. 

Table 8.13 Bottom sediments and water content of some crude oils. i 1 i ...

These products suggest that this dye may undergo reduction in bottom sediments in the environment, resulting in the subsequent release of potentially ha2ardous aromatic amines into water. 

Consider the simple initial condition t = 0 where the sohd concentration (t),o is constant across the entire shiny domain ix < r < rb where / l and l b are, respectively, the radii of the shiny surface and the bowl. At a later time t > 0, three layers coexist the top clarified layer, a middle shiny layer, and a bottom sediment layer. The air-liquid interface remains stationaiy at radius / l, while the hqiiid-slurry interface with radius i expands radiaUy outward, with t with i given by ... 

Owing to the stability of the uranyl carbonate complex, uranium is universally present in seawater at an average concentration of ca. 3.2/rgL with a daughter/parent activity ratio U) of 1.14. " In particulate matter and bottom sediments that are roughly 1 x 10 " years old, the ratio should approach unity (secular equilibrium). The principal source of dissolved uranium to the ocean is from physicochemical weathering on the continents and subsequent transport by rivers. Potentially significant oceanic U sinks include anoxic basins, organic rich sediments, phosphorites and oceanic basalts, metalliferous sediments, carbonate sediments, and saltwater marshes. " ... 

There are two main sources of Rn to the ocean (1) the decay of sediment-bound "Ra and (2) decay of dissolved "Ra in a water column. Radon can enter the sediment porewater through alpha recoil during decay events. Since radon is chemically inert, it readily diffuses from bottom sediments into overlying waters. The diffusion of radon from sediments to the water column gives rise to the disequilibrium (excess Rn) observed in near-bottom waters. Radon is also continuously being produced in the water column through the decay of dissolved or particulate "Ra. 

Fuel system fouling is related to the amount of water and sediment in the fuel. A by-product of fuel washing is the desludging of the fuel. Washing rids the fuel of those undesirable constituents that cause clogging, deposition, and corrosion in the fuel system. The last part of treatment is filtration just prior to entering the turbine. Washed fuel should have less than. 025% bottom sediment and water. 

After the said 2 to 3 hours the liquid is cooled and the bottom sediment, which has a greenish color, is filtered off. The liquid sucked off eventually is treated with active carbon, filtered and made slightly acid by means of acetic acid, at which 2-amino-benzolsulfon-amido-5-methyl-1,3,4-thiodiazol (melting point 204° to 206°C) is precipitated. 

When the water becomes stagnant, the particulate matter settles as bottom sediments. In this process it carries with it considerable amounts of plutonium, if any has been dissolved in the watter (see Table I). 

This suggests that contact with bottom sediments may mediate or catalyze the distribution of oxidation states(24). Just what the mechanism might be is not clear. 

Richert, D.A. Kennedy, B.C. McKenzie, S.W. Hines, W.G. A Synoptic Survey of Trace Elements in Bottom Sediments of the Willamette River, Oregon. Geol. Survey Circ. 715F, USGS, Reston VA, 1977 1-27. 

Fig. 14-6 Profiles of potential temperature and phosphate at 21 29 N, 122 15 W in the Pacific Ocean and a schematic representation of the oceanic processes controlling the P distribution. The dominant processes shown are (1) upwelling of nutrient-rich waters, (2) biological productivity and the sinking of biogenic particles, (3) regeneration of P by the decomposition of organic matter within the water column and surface sediments, (4) decomposition of particles below the main thermocline, (5) slow exchange between surface and deep waters, and (6) incorporation of P into the bottom sediments.

In a completely inorganic system, binding of Cu to suspended and bottom sediments would remove much of the Cu from the dissolved phase. The formation of Cu-organic complexes and the presence of organic solids complicates the analysis, however. In essence, free Cu has a strong tendency to react with many components of the system, and when... 

Varanasi, U., Stein, J.E., and Reichert, W.L. et al. (1992). Chlorinated and aromatic hydrocarbons in bottom sediments, fish and marine mammals in US coastal waters laboratory and field studies of metabolism and accumulation. In C.H. Walker and D.R. Livingstone (Eds.) Persistent Pollutants in Marine Ecosystems, Oxford, U.K. Pergamon Press, 83-118. 

Gotz R, P Friesel, K Roch, O Papke, M Ball, M, A Lis (1993) Polychlorinated-/ -dioxins PCDDs, dibenzofu-rans PCDFs, and other chlorinated compounds in the River Elbe results on bottom sediments and fresh sediments collected in sedimentation chambers. Chemosphere 27 105-111. 

Mac Kee BA, Demastre DJ, Nittrouer CA (1987) Uranium geochemistry on the Amazon Shelf Evidence for uranium release from bottom sediments. Geochim Cosmochim Acta 51 2779-2786 Mangini A, Sormtag C, Bertsch G, Muller E (1979) Evidence for a higher natural uranium content in world rivers. Natrrre 278 337-339... 

India (Borole et al. 1982) and the Forth estuary in the UK (Toole et al. 1987), nonconservative behavior of uranium was also demonstrated. In the Amazon estuary, uranium showed elevated concentrations compared to simple mixing (McKee et al. 1987). Release of uranium from bottom sediments on the shelf was suggested to be a source of dissolved (<0.4 im) uranium. However, subsequent studies in the Amazon also demonstrated that U removal (Fig. 3) occurred at salinities <12 (Swarzenski et al. 1995, Swarzenski et al. 2003). Overall, it was established that the behavior of U is highly variable examples have been found of conservative behavior as well as both additions and removal of U by interaction with sediments. 

Two important geochemical characteristics make Ra isotopes potentially useful as an estuarine tracer 1) having highly particle reactive Th isotopes residing largely in sediments as its direct radiogenic parents, which ties Ra directly to bottom sediments, and 2) exhibiting vastly different environmental behavior in fresh water and saltwater systems. 

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