Effect of nitrate on sulfur transformations in sulfidogenic sludge of a marine aquaculture biofilter (original) (raw)
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Water, Air, & Soil Pollution, 2013
Nitrate addition stimulated sulfide oxidation by increasing the activity of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), decreasing the concentration of dissolved H 2 S in the water phase and, consequently, its release to the atmosphere of a pilot-scale anaerobic bioreactor. The effect of four different concentrations of nitrate (0.12, 0.24, 0.50, and 1.00 mM) was investigated for a period of 3 days in relation to sulfide concentration in two bioreactors set up at Guadalete wastewater treatment plant (Jerez de la Frontera, Spain). Physicochemical variables were measured in water and air, and the activity of bacteria implicated in the sulfur and nitrogen cycles was analyzed in the biofilms and in the water phase of the bioreactors. Biofilms were a net source of sulfide for the water and gas phases (7.22±5.3 μmol s −1) in the absence of nitrate dosing. Addition of nitrate resulted in a quick (within 3 h) decrease of sulfide both in the water and atmospheric phases. Sulfide elimination efficiency in the water phase increased with nitrate concentrations following the Michaelis-Menten kinetics (K s =0.63 mM NO 3 −). The end of nitrate addition resulted in a recovery or increase of initial net sulfide production in about 3 h. Addition of nitrate increased the activity of NR-SOB and decreased the activity of sulfate-reducing bacteria. Results confirmed the role of NR-SOB on hydrogen sulfide consumption coupled with nitrate reduction and sulfate recycling, revealing Sulfurimonas denitrificans and Paracoccus denitrificans as NR-SOB of great importance in this process.
Effect of nitrate on biogenic sulfide production
Applied and environmental microbiology, 1986
The addition of 59 mM nitrate inhibited biogenic sulfide production in dilute sewage sludge (10% [vol/vol]) amended with 20 mM sulfate and either acetate, glucose, or hydrogen as electron donors. Similar results were found when pond sediment or oil field brines served as the inoculum. Sulfide production was inhibited for periods of at least 6 months and was accompanied by the oxidation of resazurin from its colorless reduced state to its pink oxidized state. Lower amounts of nitrate (6 or 20 mM) and increased amounts of sewage sludge resulted in only transient inhibition of sulfide production. The addition of 156 mM sulfate to bottles with 59 mM nitrate and 10% (vol/vol) sewage sludge or pond sediment resulted in sulfide production. Nitrate, nitrite, and nitrous oxide were detected during periods where sulfide production was inhibited, whereas nitrate, nitrite, and nitrous oxide were below detectable levels at the time sulfide production began. The oxidation of resazurin was attribu...
Nitrate promotes biological oxidation of sulfide in wastewaters: Experiment at plant-scale
Biotechnology and Bioengineering, 2006
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 TM ) in the works inlet. Nutriox TM 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 plantscale, provides the mechanism and supports the environmental adequacy of this strategy.
Sources of sulfide in waste streams and current biotechnologies for its removal
Journal of Zhejiang University Science, 2007
Sulfide-containing waste streams are generated by a number of industries. It is emitted into the environment as dissolved sulfide (S2− and HS−) in wastewaters and as H2S in waste gases. Due to its corrosive nature, biological hydrogen sulfide removal processes are being investigated to overcome the chemical and disposal costs associated with existing chemically based removal processes. The nitrogen and sulfur metabolism interacts at various levels of the wastewater treatment process. Hence, the sulfur cycle offers possibilities to integrate nitrogen removal in the treatment process, which needs to be further optimized by appropriate design of the reactor configuration, optimization of performance parameters, retention of biomass and optimization of biomass growth. The present paper reviews the biotechnological advances to remove sulfides from various environments.
Aquaculture Environment Interactions, 2018
A combination of biogeochemical analyses and molecular microbiological analyses were conducted to assess the environmental impact of finfish aquaculture and to elucidate the major microbial assemblages responsible for the production and removal of reduced sulfur compounds in fish-farm sediments. The average concentrations of H 2 S (123 µM) and NH 4 + (1310 µM) and the dissimilatory sulfite reductase (dsr) gene copy number (1.9 × 10 9 copies cm −3) in the sediments at the farm site were 15-, 1.5-and 2-fold higher, respectively, than those measured at the less-impacted reference site. Accordingly, the sulfate reduction rate (SRR) at the farm site (118 mmol m −2 d −1) was 19-fold higher than that measured at the reference site (6.2 mmol m −2 d −1). Analyses of dsrA and 16S rRNA gene sequences revealed that the Syntrophobacteraceae and Desulfobulbaceae groups are the major sulfate-reducing bacteria around the fish-farm sediment. Interestingly, despite the high SRR (12.2−19.6 mmol m −2 d −1), the H 2 S concentration was low (< 8 µM) in the top 0−2 cm of the fish-farm sediments. In this sulfide-mismatched zone, sulfur-oxidizing bacteria associated with Gamma-and Epsilonproteobacteria were abundant. Especially at the 1−2 cm depth, bacteria related to Sulfurovum in the Epsilonproteobacteria showed the highest relative abundance, comprising 62% of the 16S rDNA sequences. The results strongly suggest that Sulfurovum-like bacteria play a significant ecological and biogeochemical role in oxidation and reduction of reduced sulfur compounds from the organic-rich, highly sulfidic fish-farm sediments.
MIcrobiological oxidation of sulfides present in refinery sour waters by fixed bed reactors
CT y F - Ciencia, Tecnologia y Futuro
group of native bacteria with a sulfide oxidation capacity was isolated at the Instituto Colombiano del Petróleo (ICP). The bacteria were immobilized in an inert inorganic support of sintered glass that was used to evaluate a fixed packed column system working in batches as well as in a continuous mode. The experiments carried out in real wastewater and in refinery sour water show high sulfide removal percentages (over 90%) both in low and high sulfide concentrations. The appropriate operation pH is in the alkaline range (8.0 to 9.0) and it decreases as the reaction proceeds. The ability of the microbial consortium to take in the ammonia nitrogen required for their metabolic activity and a possible heterotrofic nitrification, and the phenol present in the stream as a carbon source for some of the formulated strains, is demonstrated. Sulfur mass balances are carried out quantifying it as sulfates, tiosulfates, sulfide, and elementary sulfur. The effect of operational changes on the sulfide removal percentage is evaluated obtaining a quick response of the system. A kinetic analysis was carried out and the corresponding constants derived from the Michaelis-Menten equation were calculated. The maximum removal velocity and the saturation constant are V m = 6.03•10-8 kg S/m 3 s and K s = 2.1325 •10-4 kg S/m 3. En el Instituto Colombiano del Petróleo (ICP) se aisló un grupo de bacterias nativas con capacidad bioxidadora de sulfuros. Dichas bacterias fueron inmovilizadas en un soporte inorgánico inerte de vidrio sinterizado, con el cual se evaluó un dispositivo de columna empacada de lecho fijo funcionando por lotes y en continuo. Ensayos realizados en matriz real, agua agria de refinería muestran altos porcentajes de remoción de sulfuro (mayor del 90% tanto a bajas como a altas concentraciones de este compuesto. El pH óptimo de operación se encuentra en el rango alcalino (8.0-9.0) y se produce una disminución del mismo al tiempo que se remueve el sulfuro. de igual manera se demuestra la capacidad, por parte del consorcio microbiano, de tomar el nitrógeno amoniacal y el fenol presente en la corriente, el primero, para su actividad metabólica y posible nitrificación heterotrófica y el segundo como fuente de carbono para algunas de las cepas formuladas. Se realizan balances de masa del azufre cuantificándolo como sulfatos, tiosulfatos, sulfuro y azufre elemental. Se evalúa el efecto de cambios operacionales sobre el porcentaje de remoción de sulfuros obteniéndose una respuesta rápida del sistema. Se realiza un análisis cinético y se calculan las respectivas constantes derivadas de la ecuación de Michaelis-Menten. La máxima velocidad de remoción y la constante de saturación son V m = 6.03•10-8 kg S/m 3 s y Ks = 2.1325•10-4 kg S/m 3
Sulfide-induced dissimilatory nitrate reduction to ammonia in anaerobic freshwater sediments
Fems Microbiology Ecology, 1996
Abstract: Different reduced sulfur compounds (H2S, FeS, S2O32−) were tested as electron donors for dissimilatory nitrate reduction in nitrate-amended sediment slurries. Only in the free sulfide-enriched slurries was nitrate appreciably reduced to ammonia (), with concomitant oxidation of sulfide to S0 (). The initial concentration of free sulfide appears as a factor determining the type of nitrate reduction. At extremely low concentrations of free S2− (metal sulfides) nitrate was reduced via denitrification whereas at higher S2− concentrations, dissimilatory nitrate reduction to ammonia (DNRA) and incomplete denitrification to gaseous nitrogen oxides took place. Sulfide inhibition of NO- and N2O- reductases is proposed as being responsible for the driving part of the electron flow from S2− to NH4+.