Organic Carbon Concentrations

Carbon Adsorption. Carbon adsorption is a well estabflshed and widely used technology for the removal of organics from wastewaters and gaseous streams. Carbon adsorption is a proven technology for potable water treatment and capable of reducing organic concentrations to very low or nondetectable levels. 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

These deposits would result in carbonate rock (e.g., limestone). A third source rock possibility would be evaporite rocks (e.g., salt, gypsum, anhydrite), which often contain large organic concentrations when originally deposited [26-29]. 

Fig. 2 Longitudinal changes in nutrient concentrations below the effluent input of a WWTP without tertiary treatment in La Tordera Stream. Values are the average ( SEM) of monthly measurements done over a year (see more details in [47]). In the left panel, note the net decline of ammonium concentration with concomitant net increases in nitrate concentration, suggesting a potential hot spot for nitriflcation. However, in the latest meters downstream, dissolved inorganic nitrogen (DIN) tends to decrease, which indicates net lost of DIN possibly due to denitrification. The right panel shows net changes in phosphate and dissolved organic carbon (DOC) concentrations. While phosphate does not exhibit any clear trend on an annual basis, DOC seems to decline similarly to DIN, which supports the relative dominance of denitrification...

Table 11.3. Averaged volatile organic carbon (VOC) concentrations and VOC total organic carbon (VOC TOC) ratios from different areas [92]...

In turn, the concentration of C02 in the atmosphere depends on the mass of the biosphere and its rate of decay after death, and on the carbonic-anhydrase concentrations in the sea surface. In future predictions of the rate of increase of C02 partial pressure in the atmosphere due to burning fossil fuels, it will be important to include the interaction of the atmospheric C02 with the bio-organic reservoir and the catalyzation of its absorption into the sea by means of the action of carbonic-anhydrase dissolved in sea water, considerations which have not been taken into account in past computations. 

Municipal landfill leachate typically contains dissolved organic carbon (DOC) concentrations up to several thousand (typically >1700 ppm), even in a landfill that is decades old (Christensen et al. 1998). More than 200 organic compounds have been identified in municipal landfill leachate (Paxe us 2000). Therefore, an effective chemical characterization of landfill leachate by numerous analytical techniques requires a previous isolation procedure in order to remove possible interferences. In our previous study, we tested the advantage of the ultrafiltration... 

The sediment concentrations were roughly correlated to the organic carbon content of the sediments, and the organic carbon normalised concentrations did not vary much throughout the basin. Only near one wastewater discharge were exceptionally high concentrations found. 

Assay of Enzymatic Hydrolysis of Synthetic Solid Polymers. Hydrolysis of solid polymers was measured by the rate of their solubilization, and the measurement process does not necessarily involve complete hydrolysis into the constituent parts. The rate was determined by measuring the water-soluble total organic carbon (TOC) concentration at 30 °C in the reaction mixture using a Beckman TOC analyzer (Model 915-B). In the substrate and enzyme controls, enzyme or substrate was omitted from the reaction mixture. 

Figure 16.4 Observed [ 02] in water samples from some Swiss rivers (R) and lakes (L) as a function of the dissolved organic carbon (DOC) concentrations of these waters. The results apply for noontime light intensity on a clear summer day at 47.5°N (data from Haag and Hoigne, 1986).

Activated carbon nonpolar, volatile, nonvolatile ambient temperature, large volumes limited recovery of adsorbed organics, concentrate storage, artifacts 22-23... 

The source of water samples was a 4-m3/h pilot plant on the Seine River located upstream from Paris, France. The background organic concentration ranged from 2 to 3 mg/L. The process, shown in Figure 1, included an upflow solids contact clarifier (Pulsator, Degremont, Rueil Malmaison, France) followed by rapid sand filtration (RSF). The effluent of the RSF was then split into four lines, which received various levels of ozonation followed by granular activated carbon (GAC) adsorption. Postchlorination (0.2 mg/L residual after 1 h) was used for bacterial control. 

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