Nitrate promotes biological oxidation of sulfide in wastewaters: Experiment at plant-scale

Abstract

Biogenic production of sulfide in wastewater treatment plants involves odors, toxicity and corrosion problems. The production of sulfide is a consequence of bacterial activity, mainly sulfate-reducing bacteria (SRB). To prevent this production, the efficiency of nitrate addition to wastewater was tested at plant-scale by dosing concentrated calcium nitrate (Nutriox) in the works inlet. Nutriox dosing resulted in a sharp decrease of sulfide, both in the air and in the bulk water, reaching maximum decreases of 98.7% and 94.7%, respectively. Quantitative molecular microbiology techniques indicated that the involved mechanism is the development of the nitrate-reducing, sulfide-oxidizing bacterium Thiomicrospira denitrificans instead of the direct inhibition of the SRB community. Denitrification rate in primary sedimentation tanks was enhanced by nitrate, being this almost completely consumed. No significant increase of inorganic nitrogen was found in the discharged effluent, thus reducing potential environmental hazards to receiving waters. This study demonstrates the effectiveness of nitrate addition in controlling sulfide generation at plant-scale, provides the mechanism and supports the environmental adequacy of this strategy.

Microbial Community Fingerprinting by Differential Display-Denaturing Gradient Gel Electrophoresis

“…These bacteria showed enhancement or inhibition during nitrate addition. Bacteria belonging to the Alphaproteobacteria (Agrobacterium), Firmicutes (within the Clostridiales), Betaproteobacteria (Burkholderiales), and Actinobacteria (Streptomyces) were detected as being positively The bacteria identified during this study do not correspond to major nitrate-reducing, sulfide-oxidizing bacteria, as expected from a previous study (8). We have detected mainly heterotrophic bacteria generally reported in wastewaters but with scarce potential to decipher critical nutrient-cycling steps other that organic carbon decomposition.…”

“…In a scenario dominated by heterotrophic bacteria, those representing a minor portion of the communities studied would only be occasionally detected using domainwide primer pairs. The proportion of Sulfurimonas-like relatives detected using group-specific primers by García de Lomas et al (8) constituted, at most, 0.1% of the total bacterial community. These results are in agreement with the high bacterial diversity reported in wastewaters (1,9,24) and indicate that DD-DGGE is a useful method to comparatively analyze the abundant members of bacterial communities from different treatments or sampling series.…”

Hydrogen sulphide removal from biogas by an anoxic biotrickling filter packed with Pall rings

“…These cultures were chosen as they have previously been reported in similar ambient conditions [6,31,32]. The biofilter samples (lines 3, 4 and 5) did not have bands similar to those of the pure cultures of lines 1 and 2.…”

Efecto de la biopelícula en la corrosión de aceros inoxidables

“…1). Una descripción más detallada de la EDAR-"Guadalete" puede encontrarse en la literatura [12] . Las probetas se emplazaron en los canales mediante perchas construidas en aluminio con una capacidad de 8 probetas (2 de cada aleación), sostenidas mediante aislantes eléctricos de cerámica para prevenir interferencias galvánicas.…”