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Environmental fate & pathways

Additional information on environmental fate and behaviour

Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: no guideline followed, no sufficient experimental details or details on test material, document represent oral presentation

Data source

Reference
Reference Type:
review article or handbook
Title:
Kinetics of chemical sulfide oxidation under high dissolved oxygen levels.
Author:
Sharma, K. & Yuan, Z.
Year:
2010
Bibliographic source:
Submitted for Oral Presentation, 6th International Conference on Sewer Processes and Networks, November 7th to 10th, 2010.

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The chemical sulfide oxidation was determined by experiments with domestic wastewater (filtered through 5-micron filter). Therefore pH, DO [dissolved oxygen] (via UV/VIS-based spectrometer) and dissolved sulfide measurement (via ion chromatography) were measured in a 0.75 L closed vessel at 22°C and constant pH level about 7.5.
Two series of experiments were conducted to investigate the effect of DO on the rate of chemical sulfide oxidation: first with relatively constant sulfide concentraitio and varied DO; second with varied initial sulfide and varied DO.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Other: domestic wastewater was used

Results and discussion

Any other information on results incl. tables

The results suggested, that H2S oxidation rate was independent of the DO concentration at a DO level above 5 mg/L, below which the H2S oxidation rate decreased with decreasing DO level. The oxidation rate of H2S was situated between 0.27 and 0.46 mg S/L, and this for dissolved oxygen levels between 0.5 and 14.5 mg/L (see table 1 below).

A significant amount of thiosulfate was produced during the experimet, for this reason thisulfate was assumed to be the end product of sulfitde oxidation.

  Table 1: Sulfide oxidation at different DO levels
 DO (mg/L)  12.5 -14.5  9.8 - 11.3 5.2 - 7.7   2.2 - 4.0  0.5 - 1.3
 H2S (mg S/L)  8.9 - 11.1 8.8 - 10.7  8.3 - 11.1   8.7 - 11.0  10.1 - 11.3
 Rate of oxidation (mg S/L- min)  0.42  0.46  0.41  0.30  0.27

Applicant's summary and conclusion

Conclusions:
The oxidation rate of H2S was situated between 0.27 and 0.46 mg S/L, and this for dissolved oxygen levels between 0.5 and 14.5 mg/L and thiosulfate was assumed to be the end product of sulfide oxidation.