Presence Of Anammox Bacteria Research Articles

Selecting suitable seed sludge for anammox enrichment: Role of influent characteristics and reactor operational conditions

The study investigated the suitability of three different sludge collected from diverse environments for anammox process establishment. Sludge was collected from SBR (S1) treating municipal wastewater, nitrification tank (S2), denitrification tank (S3) treating fertilizer industrial wastewater. The microbial community in the seed sludge was studied. The presence of anammox bacteria was detected only in seed sludge S2 treating high NH4+-N wastewater. Seed sludge S3 showed high abundance of denitrifiers due to NO3–-N and organic carbon rich environments in denitrification tank. The anammox start-up performances of sludge were assessed. S2 achieved start-up within 65 days whereas S1 and S3 showed longer start-up period of 79 and 93 days, respectively. S1, S2, S3 achieved nitrogen removal rate of 148.84 gN m-3day−1, 159.70 gNm-3day−1 and 120.90 gNm-3day−1, respectively. Influent NH4+-N, NO3–-N and organic carbon concentrations governed the abundance of anammox and denitrifying bacteria in seed sludge thereby impacting the anammox start-up.

Removal of ametryn and organic matter from wastewater using sequential anaerobic-aerobic batch reactor: A performance evaluation study

The present study was aimed to investigate biodegradation of 2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine (ametryn) in a laboratory-scale anaerobic sequential batch reactor (ASBR) and followed by aerobic post-treatment. Co-treatment of ametryn with starch is carried out at ambient environmental conditions. The treatment process lasted up to 150 days of operation at a constant hydraulic retention time (HRT) of 24 h and an organic loading rate (OLR) of 0.21–0.215 kg-COD/m3/d. Ametryn concentration of 4 and 6 mg/L was removed completely within 48–50 days of operation with chemical oxygen demand (COD) removal efficiencies >85% at optimum reactor conditions. Ametryn acted as a nutrient/carbon source rather causing toxicity and contributed to methane gas production and sludge granulation in the anaerobic reactor. Biotransformation products of ametryn to cyanuric acid, biuret, and their further conversion to ammonia nitrogen and CO2 are monitored during the study. Adsorption of ametryn on to reactor sludge was negligible, sludge granulation, presence of ANAMMOX bacteria, and low MLVSS/MLSS ratio between 0.68 and 0.72. The study revealed that ametryn removal occurred mainly due to biodegradation and co-metabolism processes. Aerobic post-treatment of anaerobic effluent was able to remove COD up to 95%. The results of this study exhibit that anaerobic-aerobic treatment is feasible due to easy operation, economic, and highly efficient.

Searching for indigenous anaerobic ammonium oxidizing (anammox) bacteria in South African habitats: Pretoria region

ABSTRACTIn South Africa, the information about the distribution and activity of anaerobic ammonium oxidizing (anammox) bacteria is very limited and anammox systems have not yet been tested and implemented. In this study, the existence and diversity of the anammox bacteria from various South African habitats are investigated. Batch systems were used to enrich anammox biomass from sludge collected from three Pretoria municipal wastewater treatment works. Anammox activity was tested and detected in two of the three wastewater treatment works after 90 days of primary enrichment. The activity was confirmed by consumption of both NH4 + and NO2 − in the system. The presence of anammox bacteria was also confirmed by polymerase chain reaction (PCR) amplification of the 16s rRNA of the anammox using anammox-specific primers. All clones retrieved were closely related to Brocadia species and were most abundant in all habitats tested. The maximum growth rate of anammox was also estimated on both experiments using a relatively new model.

Anammox bacteria detected in fish intestinal tract systems

Anammox bacteria serve an important ecological role in the global nitrogen cycle, enabling the coupling of ammonium and nitrite to yield dinitrogen gas (N2) under anoxic conditions. Based on PCR amplifications of genomic DNA and analysis of the 16S rRNA gene sequence, anammox bacteria was found in intestinal tracts of two types of fish, Siganus fuscescens and Mugil cephalus. Anammox bacteria identified in these fish belonged to the genera Brocadia and Kuenenia, suggesting that the living conditions of S. fuscescens and M. cephalus were under significant influence of wastewater pollution. Our results showed an association between the existence of anammox bacteria in fish intestinal tracts and sediment- or mud-eating habits of the fish involved. The presence of anammox bacteria in an animal system would provide a more comprehensive understanding on ecophysiological characteristics and distribution of anammox bacteria. This discovery might also provide useful information about the living conditions of fish, serving as an environmental indicator of anthropogenic pollution.

Anammox bacteria detected in fish intestinal tract systems

Anammox bacteria serve an important ecological role in the global nitrogen cycle, enabling the coupling of ammonium and nitrite to yield dinitrogen gas (N2) under anoxic conditions. Based on PCR amplifications of genomic DNA and analysis of the 16S rRNA gene sequence, anammox bacteria was found in intestinal tracts of two types of fish, Siganus fuscescens and Mugil cephalus. Anammox bacteria identified in these fish belonged to the genera Brocadia and Kuenenia, suggesting that the living conditions of S. fuscescens and M. cephalus were under significant influence of wastewater pollution. Our results showed an association between the existence of anammox bacteria in fish intestinal tracts and sediment- or mud-eating habits of the fish involved. The presence of anammox bacteria in an animal system would provide a more comprehensive understanding on ecophysiological characteristics and distribution of anammox bacteria. This discovery might also provide useful information about the living conditions of fish, serving as an environmental indicator of anthropogenic pollution.

Start-up of low-temperature anammox in UASB from mesophilic yeast factory anaerobic tank inoculum

Robust start-up of the anaerobic ammonium oxidation (anammox) process from non-anammox-specific seeding material was achieved by using an inoculation with sludge-treating industrial -, organics- and N-rich yeast factory wastewater. N-rich reject water was treated at 20°C, which is significantly lower than optimum treatment temperature. Increasing the frequency of biomass fluidization (from 1–2 times per day to 4–5 times per day) through feeding the reactor with higher flow rate resulted in an improved total nitrogen removal rate (from 100 to 500 g m−3d−1) and increased anammox bacteria activity. As a result of polymerase chain reaction (PCR) tests, uncultured planctomycetes clone 07260064(4)-2-M13-_A01 (GenBank: JX852965) was identified from the biomass taken from the reactor. The presence of anammox bacteria after cultivation in the reactor was confirmed by quantitative PCR (qPCR); an increase in quantity up to ∼2×106 copies g VSS−1 during operation could be seen in qPCR. Statistical modelling of chemical parameters revealed the roles of several optimized parameters needed for a stable process.

Occurrence and activity of anammox bacteria in surface sediments of the southern North Sea

We investigated the occurrence and activity of anaerobic ammonia oxidation (anammox) bacteria in sandy and muddy sand sediments of the southern North Sea. The presence of anammox bacteria was established through the detection of specific phosphocholine-monoether ladderane lipids, 16S rRNA gene, and hydrazine synthase (hzsA) genes. Anammox activity was measured in intact sediment cores (in situ rate) and in sediment slurries (potential rate) as the rate of N2 evolution from (15) N-labeled substrates and compared to the transcriptional activity of genes of anammox bacteria. The contribution of anammox to N2 production ranged between 0% and 29%. The potential rate of anammox agreed well with the abundance of anammox bacteria 16S rRNA and hzsA gene copies and the transcriptional activity of the anammox bacteria 16S rRNA gene. We found a higher abundance and activity of anammox bacteria in sediments with higher organic carbon content and also higher activity in summer than in winter. The abundance of anammox bacteria and their potential anammox rates were similar to those reported for other marine coastal sediments, suggesting that potentially they are important contributors to the nitrogen cycle in sandy sediments of shallow continental shelf areas.

Development of a simultaneous partial nitrification, anaerobic ammonia oxidation and denitrification (SNAD) bench scale process for removal of ammonia from effluent of a fertilizer industry

A simultaneous partial nitrification, anammox and denitrification (SNAD) process was developed for the treatment of ammonia laden effluent of a fertilizer industry. Autotrophic aerobic and anaerobic ammonia oxidizing biomass was enriched and their ammonia removal ability was confirmed in synthetic effluent system. Seed consortium developed from these was applied in the treatment of effluent in an oxygen limited bench scale SNAD type (1L) reactor run at ambient temperature (∼30°C). Around 98.9% ammonia removal was achieved with ammonia loading rate 0.35kgNH4+-N/m3day in the presence of 46.6mg/L COD at 2.31days hydraulic retention time. Qualitative and quantitative analysis of the biomass from upper and lower zone of the reactor revealed presence of autotrophic ammonia oxidizing bacteria (AOB), Planctomycetes and denitrifiers as the dominant bacteria carrying out anoxic oxidation of ammonia in the reactor. Physiological and molecular studies strongly indicate presence of anammox bacteria in the anoxic zone of the SNAD reactor.

Anaerobic ammonium oxidation (anammox) bacteria and sulfide‐dependent denitrifiers coexist in the water column of a meromictic south‐alpine lake

In addition to organotrophic denitrification, alternative pathways, such as anaerobic ammonium oxidation (anammox) or sulfide‐dependent denitrification may be important modes for the removal of fixed nitrogen (N) from lakes. We used Lake Lugano as a model system with which to assess possible controls on the concurrence of multiple suboxic N2 production pathways in a lacustrine water column. In the northern basin of Lake Lugano, concentration gradients of dissolved inorganic N toward the hypolimnetic redox transition zone (RTZ) indicate ammonium oxidation and nitrate reduction occurring in close vicinity. Ammonium reaches undetectable levels 15 m below the depth of oxygen disappearance, indicating its anaerobic consumption. The presence of anammox bacteria was confirmed by 16S ribosomal ribonucleic acid gene sequencing. Quantitative polymerase chain reaction revealed a maximum in anammox bacterial abundance at the same water depth where ammonium becomes exhausted. 15N‐labeling experiments indicate that anammox activity within the Lake Lugano RTZ can contribute up to ∼ 30% of total N2 production. Incubation experiments with various potential electron donors—glucose, acetate, Mn(II), Fe(II), and H2S—revealed that N2 formation was sulfide‐dependent and that organotrophic denitrification is only of minor importance for the elimination of fixed N from the Lake Lugano north basin. Maximum potential rates of anammox and chemolithotrophic denitrification were comparatively low but consistent with nutrient fluxes calculated from concentration gradients. This study provides evidence for the coexistence of anammox bacteria and sulfide‐dependent denitrifiers in the stratified water column of a lacustrine environment.

Release and conversion of ammonia in bioreactor landfill simulators

Bioreactor landfills are an improvement to normal sanitary landfills, because the waste is stabilised faster and the landfill gas is produced in a shorter period of time in a controlled way, thus enabling CH(4) based energy generation. However, it is still difficult to reach, within 30 years, a safe status of the landfill due to high NH(4)(+) levels (up to 3 g/L) in the leachate and NH(4)(+) is extremely important when defining the closure of landfill sites, due to its potential to pollute aquatic environments and the atmosphere. The effect of environmental conditions (temperature, fresh versus old waste) on the release of NH(4)(+) was assessed in experiments with bench (1 L) and pilot scale (800 L) reactors. The NH(4)(+) release was compared to the release of Cl(-) and BOD in the liquid phase. The different release mechanisms (physical, chemical, biological) of NH(4)(+) and Cl(-) release from the solid into the liquid phase are discussed. The NH(4)(+) level in the liquid phase of the pilot scale reactors starts decreasing after 100 days, which contrasts real-scale observations, where the NH(4)(+) level increases or remains constant. Based on the absence of oxygen in the simulators, the detectable levels of hydrazin and the presence of Anammox bacteria, it is likely that Anammox is involved in the conversion of NH(4)(+) into N(2). Nitrogen release was shown to be governed by physical and biological mechanisms and Anammox bacteria are serious candidates for the nitrogen removal process in bioreactor landfills. These results, combined with carbon removal and improved hydraulics, will accelerate the achievement of environmental sustainability in the landfilling of municipal solid waste.

Enriquecimento de bactérias anaeróbias oxidadoras de amônia - anammox

Bactérias anaeróbias oxidadoras de amônia (bactérias Anammox, do inglês anaerobic ammonium oxidizing bacteria) foram enriquecidas em reator em batelada sequencial (RBS), a partir de lodo proveniente de um sistema convencional de lodos ativados tratando esgoto doméstico de Belo Horizonte (MG). Após três meses de cultivo, atividade Anammox foi detectada no sistema pelo consumo de quantidades estequiométricas de NO2- e NH4+. Análises de hibridação in situ fluorescente (FISH, do inglês fluorescent in situ hybridization) confirmaram a presença de bactérias Anammox, provavelmente Candidatus Brocadia anammoxidans, e revelaram que estas representavam 53% do total de células (após 6 meses de cultivo). O desempenho do reator ao longo dos sete meses de operação demonstrou remoção quase que total de nitrito, baseada em concentração afluente de 61 a 95 mg N-NO2-/L. A eficiência máxima de remoção de amônia alcançada foi de 95%, a partir de concentração afluente de 55 a 82 mg N-NH4+/L.

Anaerobic ammonium oxidation process in an upflow anaerobic sludge blanket reactor with granular sludge selected from an anaerobic digestor

The purpose of this work was to evaluate the development of the anammox process by the use of granular sludge selected from a digestion reactor as a potential seed source in a lab-scale UASB (upflow anaerobic sludge blanket) reactor system. The reactor was operated for approximately 11 months and was fed by synthetic wastewater. After 200 days of feeding with NH4 + and NO2 − as the main substrates, the biomass showed steady signs of ammonium consumption, resulting in over 60% of ammonium nitrogen removal. This report aims to present the results and to more closely examine what occurs after the onset of anammox activity, while the previous work described the start-up experiment and the presence of anammox bacteria in the enriched community using the fluorescencein situ hybridization (FISH) technique. By the last month of operation, the consumed NO2 −N/NH4 +-N ratio in the UASB reactor was close to 1.32, the stoichiometric ratio of the anammox reaction. The obtained results from the influentshutdown test suggested that nitrite concentration would be one key parameter that promotes the anammox reaction during the start-up enrichment of anammox bacteria from granular sludge. During the study period, the sludge color gradually changed from black to red-brownish.