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Cause and Remediation of Hydrogen Sulfide Emissions from a Sodium‐Based Flue Gas Desulfurization Sludge Disposal Pond
Author(s) -
Ainsworth C. C.,
Rai D.,
Smith S. C.
Publication year - 1995
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1995.00472425002400020011x
Subject(s) - flue gas desulfurization , scrubber , flue gas , anoxic waters , hydrogen sulfide , environmental remediation , sulfur , chemistry , environmental chemistry , wet scrubber , environmental engineering , gypsum , environmental science , waste management , contamination , geology , ecology , organic chemistry , engineering , biology , paleontology
A flue gas desulfurization (FGD) sludge disposal pond with a history of H 2 S emissions to the atmosphere was studied to determine the cause of emissions and remediation strategies. The pond receives sludge and associated waters from a single‐pass Na 2 CO 3 flue gas scrubber unit. The pond water is a sodic alkaline brine with large SO 3 and S 2 O 3 concentrations (>5000 mg L −1 ), and hence, an elevated chemical O 2 demand. The pond water H 2 S concentrations are small as a result of periodic H 2 O 2 additions. The sediments, however, have as much as 3500 mg L −1 H 2 S in the pore water. The production of H 2 S appeared to originate from the sediments and diffuses through the anoxic water column with little oxidation. Large concentrations of the reduced sulfur species SO 3 and S 2 O 3 were present as a result of the flue gas desulfurization process and incomplete oxidation of H 2 S. The pond was reconstructed to circulate the water through an air injection system that was designed to oxidize the SO 3 and S 2 O 3 to SO 4 , and thereby reduce the chemical O 2 demand. After the installation of the air injection system, emissions of H 2 S ceased and the concentrations of SO 3 and S 2 O 3 were reduced by at least a factor of 10 within 3 to 4 wk. The production of H 2 S in the sediments, however, did not appear to be affected, nor did it appear that it will be reduced in the future by the air injection system.