Drain studies

As stated in the introduction to the previous chapter, adsorption is described phenomenologically in terms of an empirical adsorption function n = f(P, T) where n is the amount adsorbed. As a matter of experimental convenience, one usually determines the adsorption isotherm n = fr(P), in a detailed study, this is done for several temperatures. Figure XVII-1 displays some of the extensive data of Drain and Morrison [1]. It is fairly common in physical adsorption systems for the low-pressure data to suggest that a limiting adsorption is being reached, as in Fig. XVII-la, but for continued further adsorption to occur at pressures approaching the saturation or condensation pressure (which would be close to 1 atm for N2 at 75 K), as in Fig. XVII-Ih. 

Air or biological oxidation of pyrite leads to sulfate formation and dilute sulfuric acid in the mine drainage. This pollutes streams and the water supphes into which the mine water is drained. Means of controlling this problem are under study. 

The process involved in the incident is concerned with the separation of crude into three phases. The crude is pumped into a two stage separation process where it is divided into three phases oil, gas, and water. The water is cleaned up and dumped to drain. The remaining mixture of oil and gas is then pumped into the main oil line where it is metered and sent on for further processing. A simplified process diagram is shown in Figure 7.1. The case study described here is centered on a flange leak in one of the oil pipeline pumps (pump A) and its associated pressure relief valve piping. 

Soil water flow is decidedly episodic. During dry times the water solutions in the soil are probably fairly concentrated and not very reactive. Time-averaged reaction rates should be roughly proportional to the fraction of time reacting minerals are in contact with thermodynamically imdersaturated (and reactive) water. In a study of the relationship between denudation rate and runoff for rivers draining igneous and metamorphic rock in Kenya, Dunne (1978) obtains the relationship of (denudation rate in tons/km per year) = 0.28 (runoff in mm/ year)°. ... 

Several studies have been conducted to measure methyl parathion in streams, rivers, and lakes. A U.S. Geological Survey (USGS) of western streams detected methyl parathion in five river samples taken from four states during a 14-month period in 1970 and 1971. The amount of methyl parathion detected ranged from 0.04 to 0.23 pg/L (Schultz et al. 1973). A later and more extensive USGS study analyzed water samples from major rivers of the United States four times yearly in the period of 1975-1985. Of the 2,861 water samples, 0.1% had detectable levels of methyl parathion (Gilliom et al. 1985). In a study of Arkansas surface waters, samples of lake and river/stream water were collected and analyzed over a three-year period (Senseman et al. 1997). Of the 485 samples collected, methyl parathion was found in one river/stream sample at a maximum concentration of 3.5 pg/L. Results from an EPA study in California detected methyl parathion in 3 of 18 surface drain effluent samples at concentrations of 10-190 ng/kg. Subsurface drain effluent water had concentrations of 10-170 ng/kg in 8 of 60 samples (lARC 1983). 

As a result of volatilization, significantly elevated indoor air levels of trichloroethylene can occur in homes that use water supplies contaminated with trichloroethylene (Andelman 1985a). The transfer of trichloroethylene from shower water to air in one study had a mean efficiency of 61% which was independent of water temperature (McKone and Knezovich 1991). The study authors concluded that showering for 10 minutes in water contaminated with trichloroethylene could result in a daily exposure by inhalation comparable to that expected by drinking contaminated tap water. Another study using a model shower system found that, in addition to shower spray, shower water collecting around the drain could be an important source of volatilized trichloroethylene, and the fraction volatilized could be affected by spray drop size and flow rate (Giardino et al. 1992). 

Some bacteria can give products a rancid smell others can impart the "sweet" odour of dirty drains by the production of certain pyrazine derivatives. Other bacteria, known as sulphate reducers, for example Desulphovibrio desulphuricans, are able, under anaerobic conditions, to utilise oxygen from sulphates leading ultimately to the formation of hydrogen sulphide. Opperman and Goll (1984) in their study of contaminated emulsion paints concluded that more than a quarter were infected with these and other anaerobic organisms. 

Materials and methods. Each species studied was grown in the greenhouse in a growth unit constructed from 10 cm PVC drain pipe and T-fittings, as described previously. The growth units were filled with an artificial soil mix of perlite/coarse sand/coarse vermlculite 3/2/1 by volume. On the second and fifth day of each week four liters of a full strength Peter s Hydro-sol solution plus calcium nitrate (36.7 g/37.8 liters plus 17.0 g Ca(N03 )2 /37.8 liters) were added to each growth... 

Actinomycetes are typically most abundant in well drained, circumneu-tral to alkaline soils having abundant organic matter. Water-logging and low pH may reduce populations (37, 38). The numbers of actinomy-cetous organisms isolated from the various soil samples in our study follow this pattern. No clear trend emerged as to a particular edaphic or biotic factor causing an increase in the proportion of inhibitory isolates in a soil sample. 

So far there has not been any solution for this problem. In this study however, the problem is analyzed and explained. The risk increases with the soil depth, i.e., long casing. Some of the suggested principal solutions will solve the freezing problem by controlling, reducing or draining the pressure. 

Three of five men, who lost consciousness within a few minutes of entering a partially drained underground liquid manure storage tank, died before reaching the hospital autopsy showed that two had massive liquid manure pulmonary aspiration, while the third had fulminant pulmonary edema without manure aspiration (Osbem and Crapo 1981). Markedly elevated heart-blood sulfide-ion levels indicated significant hydrogen sulfide exposure. Air samples analyzed about a week after the accident detected only 76 ppm of hydrogen sulfide, but the study authors noted that the environmental conditions were probably different (e g., warmer weather, less-concentrated manure). 

Other experiments are planned to study the location, distribution and resuscitation of ultramicrobacteria in large three-dimensional sandpacks. Such studies will allow a more realistic approximation of reservoir conditions than the unidirectional core studies. We do not consider that the ultramicrobacteria will reach or grow in areas where residual oil is located. Selective plugging involves blocking the high permeability zones already drained of oil. We consider that the injection of ultramicrobacteria will be carried, like waterflood operations, to the areas of the strata already drained of oil and permit them to disperse through pore spaces and resuscitate in these areas. 

In summary, care must be taken to inject nutrients that do not encourage rapid growth as undesirable shallow bacterial plugs form (Fig. 3F). With the correct nutrient package, such as SCM in this instance, a deep plug will form throughout the strata (Fig. 3D). In conclusion, our laboratory based studies demonstrate that starved bacteria may be used to physically block rock strata already drained of oil. Further recovery operations can then deal with strata still containing oil and thus enhance recovery rates. 

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