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Inhibition of Sulfide Generation in a Reclaimed Wastewater Pipe by Nitrate Dosage and Denitrification Kinetics
Author(s) -
RodríguezGómez Luis E.,
Delgado Sebastián,
Álvarez Manuel,
Elmaleh Samuel
Publication year - 2005
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 - 10.2175/106143005x41762
Subject(s) - denitrification , wastewater , nitrate , sulfide , chemistry , kinetics , environmental science , environmental chemistry , environmental engineering , waste management , nitrogen , engineering , organic chemistry , physics , quantum mechanics
Sulfide generation should be avoided during wastewater transportation. The efficiency of nitrate dosing for the inhibition of sulfide generation was evaluated during reclaimed wastewater transport with two nitrate doses, 2.5 and 5 mg/L nitrate‐nitrogen (NO 3 ‐N). A calcium nitrate [Ca(NO 3 ) 2 ] solution was injected at the beginning of the 61‐km‐long gravity pipe, which is part of the Reclaimed Wastewater Reuse System of South Tenerife (Spain). During transportation, after dissolved oxygen depletion, a denitrification process took place. With the 5 mg/L NO 3 ‐N dose, nitrate was not completely removed at the end of the pipe, whereas with 2.5 mg/L NO 3 ‐N, a complete denitrification was achieved. Sulfide generation was completely inhibited with the 5 mg/L dose. However, with 2.5 mg/L, sulfide generation was not completely inhibited but delayed and minimized to a great extent. Denitrification was stoichiometrically limited by the availability in biodegradable matter. An empirical equation enables one to predict the nitrate concentration.