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Oxygen Demand of Fresh and Stored Sulfide Solutions and Sulfide‐Rich Constructed Wetland Effluent
Author(s) -
Chan Carolyn,
Farahbakhsh Khosrow
Publication year - 2015
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 - 10.2175/106143015x14362865225951
Subject(s) - chemical oxygen demand , sulfide , biochemical oxygen demand , effluent , chemistry , hydrogen sulfide , turbidity , wastewater , environmental chemistry , pulp and paper industry , sodium sulfide , environmental engineering , environmental science , inorganic chemistry , ecology , sulfur , organic chemistry , engineering , biology
This study investigated the contribution of hydrogen sulfide to biological oxygen demand (BOD 5 ) and chemical oxygen demand (COD) in wastewater effluents, and documented the effect of storage times and conditions on the BOD 5 and COD of pH‐adjusted sodium sulfide solutions as well as graywater wetland effluent. Initial COD measurements of sulfide solutions were 84‐89% of the theoretical oxygen demand (ThOD), 1.996 mg O 2 /mg S, whereas unseeded BOD 5 measurements were 55‐77%. For sulfide solutions, all storage conditions led to declines of >15% (COD, BOD 5 ), and >31% (sulfide). For wetland effluent, storage without headspace was effective in reducing COD losses (3.7%), compared to storage with headspace (17%), and affected changes in turbidity, UVA‐254 and pH. The results suggest that storage times and conditions should be controlled and reported when reporting BOD 5 and COD of sulfide‐rich samples. Wetland models representing sulfate reduction as a method of COD removal may need to be reconsidered.