Plant water balance

Laboratory analysis

Plant water balance

Water usage analysis

Existing flow records

Field measurements

Meter records

Dye studies

FIG. 7.3.1 Components of an industrial wastewater survey. (Reprinted, with permission, from R.A. Corbitt, 1990, Wastewater disposal, Chap. 6 in Standard handbook of environmental engineering, edited by R.A. Corbitt (New York: McGraw-Hill, Inc.)

water characteristics at these NARFs varied due to differences in missions and operations. Thus, the survey required characterization of wastewaters from all six NARFs to adequately represent aircraft paint stripping wastewater generated by the U.S. Navy.

The survey team selected 24 test parameters to characterize the quality of the aircraft paint stripping wastewater. Some parameters were important in monitoring chemical or biological treatment, while others were related to monitoring requirements for discharge regulations. The four parameters identified as most important, either because of high concentrations or limitations imposed by regulatory agencies, were oil and grease, phenol, chromium, and total toxic organics (TTO). The TTO parameter includes up to 110 toxic organics identified by the U.S. EPA. It is being incorporated into discharge permits by various regulatory agencies. The EPA set a value of 2.13 mg/l for TTO as the wastewater pretreatment standard for metal finishing industries, and aircraft paint stripping wastewater is in this category. The 2.13 mg/l value is based on the summation of all quantifiable concentrations greater than 0.01 mg/l for the 110 listed toxic organics.

To reduce sample analysis costs, the TTO analyses conducted during the survey excluded organics not present in paint stripping wastewater, including PCBs and pesticides. Thus, the analyses for TTO included only volatile organics (EPA Methods 601 and 602), acid ex-tractables, and base neutral extractable organics (EPA Method 625). A total of eighty-four toxic organic com pounds were analyzed from the list of 110 compounds; the twenty-six compounds not analyzed were PCBs and pesticides.

In nearly two months of site visits to the six NARFs, eighty-three aircraft paint stripping wastewater samples were collected, including nineteen composite samples (collected by automatic samplers) and sixty-four grab samples. For each sample, twenty-three analytical tests were performed. In addition, the TTO tests were performed on seventeen grab samples.

Table 7.3.7 shows the results of the analyses. Naval aircraft paint stripping wastewater is characterized by high organic pollutant contents and, except for chromium, low concentrations of heavy metals. The concentration level of oil and grease is generally lower than 500 mg/l; however, for one NARF, it averaged as high as 1215 mg/l. The average pH values varied from 5.2 to 9.4. Averages for phenol concentrations were typically in the hundreds range, but it was as high as 800 to 1300 mg/l for two NARFs. Due to the use of a nonphenolic paint stripper, one NARF (North Island) was able to keep its wastewater phenol concentration to around 1 mg/l; however, at this NARF, both stripper and labor usage increased due to the reduced effectiveness of the phenol-free stripper. The average TDS and SS values are typical for many wastewaters. Total chromium levels varied from 1.6 to 76 mg/l, while hexa-valent chromium levels ranged from below 0.002 to about 13 mg/l. For the TTO parameter, values ranged from 124 to 2765 mg/l.


Concentrations (mg/l, except for pH)

Norfolk Cherry Pt Jacksonville Pensacola NorIs Alameda

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Norfolk Cherry Pt Jacksonville Pensacola NorIs Alameda

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