Open AccessInfluence of Nitrate and Sulfate on the Anaerobic Treatment of Pharmaceutical Wastewater
Author(s) -
Rodríguez M. J.,
Garza G. Y.,
Aguilera C. A.,
Martínez A. S. Y.,
Sosa S. G. J.
Publication year - 2005
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.200520101
Subject(s) - sulfate , nitrate , chemistry , wastewater , chemical oxygen demand , sulfide , denitrification , bioreactor , pulp and paper industry , anaerobic respiration , environmental chemistry , sewage treatment , anaerobic exercise , nitrogen , environmental engineering , environmental science , organic chemistry , biology , physiology , engineering
Anaerobic treatment of wastewater from the pharmaceutical industry, which contained about 3.2 g/L of sulfate, was carried out in an Upflow Anaerobic Sludge Blanket (UASB) reactor. After a startup period of 120 days, a chemical oxygen demand (COD) removal efficiency of more than 90 % was obtained along with an organic loading rate (OLR) of 1.5 g COD/(L day). During the same period, the sulfate removal was about 90 %. However, the performance of the reactor was affected when the loading rate was increased to 2.09 g COD/(L day). It was found that the accumulation of sulfides, combined with a decrease in the pH, affected the reactor performance. In batch reactor studies with pharmaceutical wastewater it was observed that methane production began only after the initiation of nitrate consumption. The denitrification process can inhibit sulfate reduction at high nitrate concentrations, but compared to reactors without nitrate, the sulfate reduction process and sulfide formation were quickly initiated at low nitrate concentrations. The methanogenic activity was however affected by the presence of more than 2 g/L of sulfate.