Initial contamination

Since the low-momentum supply system should enhance the efficiency of an exterior hood by supplying low-momentum airflow to a source, the system can be applied to practically any sources where an exterior hood can be used. In particular, it is effective to apply the system when an exterior hood cannot be placed close to a source or the exhaust direction is different from the initial contaminant release direction. 

Predictive microbiology using growth models should be implemented in order to follow the microbial behavior in fruit osmotically dehydrated/ impregnated and to compute their shelf life as a function of process variables, such as concentration of osmotic medium, initial contamination of the solution, and fruit storage temperature. 

It is assumed that at time zero a defined quantity of Dursban enters a lake and is distributed subsequently between the fish, the soil and the plants. The soil and plants are lumped together as one compartment. The quantities in each compartment are expressed as a percentage of the initial contamination. 

The extractable contamination concentration from 100% recycled PET bottles into all kinds of foodstuffs (aqueous, alcoholic and fatty) was shown to be several orders of magnitude below the FDA threshold of regulation, even if the initial contaminant concentration was significantly above the values found in the waste stream [136],... 

In many cases, a trace element retained on the subsurface soM phase may undergo chemical reactions that induce a hysteresis phenomenon during the release process. A relevant example of hysteresis due to precipitation of some of the initial contaminants is given by the behavior of Cr(VI), an industrial contaminant, which in the subsurface environment may be subject to reduction reactions. When an available source of electrons is present, such as organic matter, Cr(VI) is reduced to Cr(III) the rate of this reaction increases with decreases in pH (Ross et al. 1981). 

Characteristics of soil Quantity of waste Utility/fuel rates Moisture content of soil Initial contaminant concentration Characteristics of residual waste Waste handling/preprocessing Target contaminant concentration Amount of debris with waste Labor rates... 

Initial contaminant concentration Target contaminant concentration Soil characteristics Waste quantity... 

Among the factors that affect the cost per unit price are initial contaminant concentration, target contaminant concentration, moisture content of the soil, and soil characteristics (D10018L, p. 13). 

According to the vendor, the estimated price of remediation using a soil slurry-sequencing batch reactor system was 50 to 110/m of waste treated in 1995. Costs are usually 1.5 to 2 times less than excavation and inceration. The quantity of waste and initial contaminant concentration were cited as the most significant factors effecting price (D10036N, p. 15 D15328G, p. 7). 

The vendor estimates the treatment cost with a biofilter at 5 to 10/kg of waste. Factors that have a significant effect on the unit price are the quantity of waste, the target contaminant concentration, the initial contaminant concentration, and the targeted final concentration of the treated contaminant. These price estimates do not always include aU indirect costs (D10048R,... 

Although many of the costs for chemical oxidation technologies will be site specific, chemical costs will generally average 15 to 30% of the total remediation costs. Factors that influence chemical costs will include the chemical oxygen demand (COD) of the contaminated media, pH, the size of the site, and initial contaminant concentrations (D22442A, pp. 19, D-1). 

In 1997, CF Systems provided a general solvent extraction price range of 75 to 400 per ton of contaminated material. The qnantity of waste requiring remediation, the characteristics of the soil, the target contaminant concentrations, and the initial contaminant concentrations wonld most strongly affect the nnit treatment price of the process (D20539A, p. 4-22, 4-24). 

In 1996, Delphi estimated the cost of processing wastes at 2.50 to 10.00/kg. Among the factors listed as affecting cost were quantity of waste, labor rates, initial contaminant concentration, characteristics of residual waste, waste handling and pretreatment, amount of debris, utility/fuel rates, and target contaminant concentration (D13821G, p. 24). 

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