Site Description:

A one to two acre lagoon is used for the deposition of waste water from a toluene amination operation and as a cattle stock tank.  Target wastes were toluene and ammonia.  Discharge is sporadic.  Two sampling sites were selected.

Examination of the lagoon on revealed a slightly murky lagoon.  Close examination of the lagoon revealed few, if any, water insects or amphibians.  A pronounced solvent odor was evident on the samples.  Microscopic examination revealed no microscopic life except for a few bacterial forms.  Plate tests were negative for heterotrophic aerobic or facultative anaerobic microorganisms.  The pond was diagnosed as ammonia toxic with possible contributions due to solvent contamination.  Ammonia levels were high (Table 1).

 Treatment:

The pond was treated once a week for three weeks with M1000H* and Mega-Bac products along with nutrients designed to force ammonia assimilation.

Results:

The initial ammonia level (assayed by EPA Nessler's method) was 75 and 90 ppm.  After initial treatment, the level rose to 110 and 155 ppm, and then fell to 23 and 24 ppm after the last treatment.  The initial toluene level (assayed by GC, with purge and trap) was 18 ppb.  At the two week treatment period and still at four weeks the toluene level was less than 0.1 ppb.

After the three week treatment period, the pond was monitored for an additional two weeks.  A slight rise in ammonia level was seen -- 30 and 25 ppm, still far below levels seen initially.

A variety of other ions were assayed per client interest (Table 2).  SO₄ and NO₃ levels fell during treatment as well.  C1^- levels were not excessively high.

Within two weeks of treatment, there was a substantial increase in bacterial forms.  Diatoms resembling Actinastrum, Navicula, Stauroneis, and Eudorina were seen.  Protozoans resembling Colpoda and Stylonychia were present.  The appearance of this microscopic life even in the presence of high ammonia suggests that toxicity in the pond was due to some other chemical agent, perhaps toluene or some other hydrocarbon. 

Conclusion 

There was a dramatic decrease in the target analytes, toluene and ammonia, after treatment.  The fact that the other analyte levels declined at a different rate from the ammonia suggests strongly that true remediation occurred rather than dilution due to rainfall.  It is possible that the cattle are continually adding feces to the water, and ammonia levels may rise as a consequence.

TABLE 1

AMMONIA LEVELS (mg/liter)

TABLE 2

MISCELLANEOUS ANALYTES (mg/liter)