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Reduction of hydrogen sulfide gas in a small wastewater collection system using sodium hydroxide
Author(s) -
Wiley Patrick E.
Publication year - 2019
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.1002/wer.1053
Subject(s) - hydrogen sulfide , sodium sulfide , wastewater , chemistry , sodium hydroxide , waste management , reduction (mathematics) , environmental science , environmental chemistry , environmental engineering , inorganic chemistry , organic chemistry , engineering , sulfur , geometry , mathematics
The Kennebunk Sewer District collection system experienced H 2 S‐induced corrosion downstream of terminus manholes for the Wells Road and Boothby Road pumping stations. An automated odor control system using sodium hydroxide (Na OH ) was developed to mitigate further corrosion. System performance was quantified by recording the [H 2 S] in the terminus manholes before and after Na OH treatment. Preliminary evaluation at the Wells Road facility demonstrated significant ( p < 0.001) reduction in the average [H 2 S] between the treatment (4.8 ± 0.3 ppm) and control (67 ± 1.5 ppm). Permanent systems installed at both facilities in 2017 yielded similar positive results. The average [H 2 S] in the Wells and Boothby Road terminus manholes reduced from 89.4 ± 1.0 to 8.0 ± 0.1 ppm and from 7.9 ± 0.2 to 0.82 ± 0.06 ppm, respectively. This work demonstrates the ability of the Na OH system presented here to minimize emission of corrosive H 2 S gas in small collection systems. Practitioner points Biologically‐produced hydrogen sulfide (H 2 S) gas corrodes sewer collection system components and results in premature asset failure. Maintaining wastewater pH above 8.5 by injecting sodium hydroxide (NaOH) minimizes H 2 S emission by shifting the molar distribution of sulfur species and partially inhibiting the anaerobes that produce H 2 S. The practical application of this approach may be limited to small wastewater collection systems.