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1.
J Environ Manage ; 286: 112255, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33647672

RESUMEN

To date, the partial nitrification-Anammox (PN-A) granular sludge size has been exclusively analyzed in synthetic substrates. In this work, different ranges of granular size of PN-A sludge were studied at low oxygen concentration using real industrial wastewater as, well as a synthetic substrate. The granular sludge was characterized by the specific nitrification activity (SNA), specific anammox activity (SAA), and granule sedimentation rate. The relative abundance of the bacterial consortium was assessed for each range of diameters through the fluorescence in situ hybridization (FISH) technique. SNA exhibits a direct association with the specific surface of granules, which proves the importance of the outer layer in the nitrification process. Even more critical, the flocculent sludge allowed the stability of the nitrifying activity. The SAA showed different performances faced the real industrial and synthetic substrates. With the synthetic substrate, the SAA decreased at higher diameter ranges, whereas with the industrial substrate, the SAA increased at higher diameter ranges. This situation is explained by the oxygen protection in the sludge maintained with industrial wastewater. The relative abundance of heterotrophic bacteria increased from 9.6 to 22%, due to the presence of organic matter in the industrial substrate. The granular sedimentation rate increased with the diameter of the granules with a linear correlation (R2 > 0.98). Thus, granular sizes can be selected through sedimentation rate control. A linear correlation between SAA and granular sludge diameter ranges was observed. With this correlation, an error of less than 11% in the prediction of SAA was achieved. The use of diameter measurement and granular sedimentation rate as routine techniques could contribute to the control and start-up of PN-A reactors. In the same sense, organic matter present in defined concentrations, can be beneficial for the granular sludge stability, and thus, for nitrogen removal.


Asunto(s)
Nitrificación , Aguas Residuales , Reactores Biológicos , Hibridación Fluorescente in Situ , Nitrógeno , Oxidación-Reducción , Aguas del Alcantarillado
2.
Bioresour Technol ; 329: 124903, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33662853

RESUMEN

Synchronous sludge reduction and nitrogen removal have attracted increasing attention, while the underlying mechanisms of diverse nitrogen metabolism within the complicated processes remain unclear. Four anoxic/oxic membrane bioreactors, three of which were upgraded by anaerobic side-stream reactors (ASSR) and carriers (APSSR-MBRs), were operated to determine effects of hydraulic retention time of ASSRs. APSSR-MBRs achieved more significant nitrogen removal and higher nitrate uptake rate because of more denitrifying bacteria and the supernumerary release of secondary substrates. Ammonia uptake rate showed the diverse Nitrospira preceded over anaerobic decay and sulfide inhibition in the ASSR, and made the reactor exhibit higher nitrification capacity. Metagenomic analysis indicated that APSSR-MBRs showed higher abundances of genes related to nitrogen consumption processes, and higher abundances on the carriers, confirming their pivotal roles in nitrogen metabolism. This study provided novel perspectives to build a bridge between process model and nitrogen metabolism in the sludge reduction system..


Asunto(s)
Nitrógeno , Eliminación de Residuos Líquidos , Anaerobiosis , Reactores Biológicos , Desnitrificación , Redes y Vías Metabólicas , Aguas del Alcantarillado
3.
Bioresour Technol ; 329: 124889, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33662854

RESUMEN

The study aims to investigate the feasibility of anaerobic co-landfilling of effluent treatment plant sludge (ETPS) from paper mill and municipal solid waste (MSW) in prismoidal shaped simulated anaerobic landfill bioreactors. Both ETPS and MSW were co-disposed in 0:100 (R1), 25:75 (R2), 50:50 (R3) and 75:25 (R4) ratios. Periodic assessments of leachate characteristics and biomethane production were carried out for 300 days. ETPS co-disposal with MSW showed considerable reduction in biochemical oxygen demand of leachate (R2: 95.9%, R3: 97.5% and R4: 93.2%). Moreover, cumulative methane gas generations were 2.974, 6.085 and 4.653 times more in R2, R3 and R4 bioreactors as compared to R1. Gompertz growth model was found in well-fitting for methane generation with the observed data. Correlogram plotted among leachate parameters exhibited exclusive relationships and justified leachate trends. This simulation of co-landfilling could be baseline study for the implementation of technology at pilot scale.


Asunto(s)
Eliminación de Residuos , Contaminantes Químicos del Agua , Anaerobiosis , Reactores Biológicos , Descontaminación , Metano , Aguas del Alcantarillado , Residuos Sólidos , Instalaciones de Eliminación de Residuos , Contaminantes Químicos del Agua/análisis
4.
Bioresour Technol ; 329: 124906, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33662855

RESUMEN

In order to enhance nitrogen removal through anammox process in the full-scale swine wastewater treatment plant, an innovative regulation strategy of nitrate-based carbon dosage and intermittent aeration was developed to apply the combined biological nitrogen removal process in a full scale anaerobic-anoxic-oxic (A2/O) system. TN removal efficiency reached at 65.5 ± 6.0% in Phase 1 with decreasing external carbon dosage in influent due to the reduction of return nitrate concentration, and it increased to 83.5 ± 6.7% when intermittent aeration was adopted in oxic zone and external carbon source was stopped adding into influent in Phase 2. As a result, the energy consumption for the swine wastewater treatment decreased from 1.93 to 0.9 kW h/m3 and 4.18 to 2.57 kW h/kg N, respectively. Microbial community analysis revealed that the average abundances of Candidatus Brocadia increased from 0.76% to 2.43% and removal of TN through anammox increased from 39% to 77%.


Asunto(s)
Desnitrificación , Purificación del Agua , Animales , Reactores Biológicos , Nitrógeno , Oxidación-Reducción , Aguas del Alcantarillado , Porcinos , Aguas Residuales
5.
J Environ Manage ; 286: 112267, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33667820

RESUMEN

Antibiotic pollution is becoming increasingly severe due to its extensive use. The potential application of the anaerobic ammonium oxidation (anammox) process in the treatment of wastewater containing antibiotics has attracted much attention. As common antibiotics, spiramycin (SPM) and streptomycin (STM) are widely used to treat human and animal diseases. However, their combined effects on the anammox process remain unknown. Therefore, this study systematically evaluated the response of the anammox process to both antibiotics. The half maximal inhibitory concentrations of SPM and STM were determined. The continuous-flow anammox system could adapt to SPM and STM at low concentrations, while antibiotics at high concentrations exhibited inhibitory effects. When the concentrations reached 5 mg L-1 SPM and 50 mg L-1 STM, the nitrogen removal efficiency dramatically decreased and then rapidly recovered within 8 days. Correspondingly, the abundances of dominant bacteria and genes also changed with antibiotic concentrations. In general, the anammox process showed a stable performance and a high resistance to SPM and STM, suggesting that acclimatization by elevating the concentrations was beneficial for the anammox process to obtain resistance to different antibiotics with high concentrations. This study provides guidance for the stable operation of anammox-based biological treatment of antibiotics containing wastewater.


Asunto(s)
Compuestos de Amonio , Macrólidos , Aminoglicósidos , Anaerobiosis , Animales , Antibacterianos , Reactores Biológicos , Humanos , Nitrógeno , Oxidación-Reducción , Aguas Residuales
6.
J Environ Manage ; 286: 112229, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33667821

RESUMEN

Up-flow anaerobic bioreactors are widely applied for high-rate digestion of industrial wastewaters and rely on formation, and retention, of methanogenic granules, comprising of dense, fast-settling, microbial aggregates (approx. 0.5-4.0 mm in diameter). Granule formation (granulation) mechanisms have been reasonably well hypothesized and documented. However, this study used laboratory-scale bioreactors, inoculated with size-separated granular sludge to follow new granule formation, maturation, disintegration and re-formation. Temporal size profiles, volatile solids content, settling velocity, and ultrastructure of granules were determined from each of four bioreactors inoculated only with small granules, four with only large granules, and four with a full complement of naturally-size-distributed granules. Constrained granule size profiles shifted toward the natural distribution, which was associated with maximal bioreactor performance. Distinct morphological features characterized different granule sizes and biofilm development stages, including 'young', 'juvenile', 'mature' and 'old'. The findings offer opportunities toward optimizing management of high-rate, anaerobic digesters by shedding light on the rates of granule growth, the role of flocculent sludge in granulation and how shifting size distributions should be considered when setting upflow velocities.


Asunto(s)
Euryarchaeota , Eliminación de Residuos Líquidos , Anaerobiosis , Reactores Biológicos , Crecimiento y Desarrollo , Aguas del Alcantarillado
7.
Bioresour Technol ; 329: 124912, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33667990

RESUMEN

The active sludge treating propylene oxide saponification wastewater has heavy salt concentration and is hard to treat. The integration of the residual sludge treatment with polyhydroxyalkanoates (PHA) production may provide an economic and environment friendly solution. PHA production was therefore studied in two sequencing biological reactors with effective volume of 30 L using the active sludge. The two reactors, named as SBR-I and SBR-II, were fed with acetic acid, and a mixture of acetic acid and propionic acid respectively. PHA was obtained with a yield of 9.257 g/L in SBR-II. Also, the proportion of 3-hydroxyvalarate was enhanced from 5% to 30% in comparison to SBR-I (5.471 g/L). Illumina MiSeq and Pacific Biosciences sequencing platforms were used to evaluate the community structure, which revealed that the bacterial genera showed a high degree of diversity in the PHA accumulating microbial community. Azoarcus was the most dominant PHA accumulating microorganism after acclimation.


Asunto(s)
Polihidroxialcanoatos , Aguas del Alcantarillado , Reactores Biológicos , Compuestos Epoxi , Ácidos Grasos Volátiles , Aguas Residuales
8.
J Environ Manage ; 286: 112254, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33676131

RESUMEN

In this study, the pure terephthalic acid sludge was treated by a drying process which was an economical and environmentally method. The water change and metabolic pathways for bacterial community function prediction were analyzed. The microbial community changes were studied by high-throughput sequencing to draw the dynamic succession model. Then multiple statistics was used to determine the key factors of the reduction. The results showed that the main stage of water loss in the PTA sludge drying process was the high temperature period where the water lost by evaporation accounted for more than 90% of the total removal. The main metabolic pathways for bacterial community function were amino acid (7.72%-8.71% of Kyoto encyclopedia of genes and genomes relative abundance and 8.26%-9.51% of Cluster of orthologous groups of proteins relative abundance) and carbohydrate metabolism. The model describing the dynamic succession of microbial communities showed that the dominant bacteria changed from Nitrospira, Novosphingobium and Azohydromonas to Pseudomonas, Paeniglutamicibac and Pelotomaculum. The key factors for water loss were Gemmatimonas, Novosphingobium and Azohydromonas with the correlation coefficients of 0.887, 0.772, 0.783, respectively; the key factors for dry matter loss were Pelotomaculum, total organic matter, dissovlved organic carbon and carbon/nitrogen ratio; the key factors for toxic substance loss were Brevundimonas, Novosphingobium and Gemmatimonas. These results provided theoretical support for the application and demonstration for hazardous waste sludge reduction.


Asunto(s)
Aguas del Alcantarillado , Agua , Reactores Biológicos , Desecación , Nitrógeno/análisis , Aguas Residuales
9.
Bioresour Technol ; 329: 124925, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676352

RESUMEN

In this study, an integrated device with scrubbing and biochemical treatment functions was used, and partial nitrification (PN)-Anammox and sulfur autotrophic denitrification (SADN) processes were coupled in a biochemical treatment pond to explore the feasibility of in-situ autotrophic removal of NH3 and H2S. The results showed that the removal efficiency of NH3 and H2S in waste gas are 95% and 87.5% respectively. The scrubbing liquid was efficiently treated in the biochemical treatment pond. Nitrogenous compounds weren't accumulated in liquid and converted to N2 by SADN and PN-Anammox coupling system. S2- was mainly used by SADN process to reduce NO3-. The scrubbing liquid processed by the biochemical treatment pond was refluxed to the scrubber to achieve continuous absorption of NH3 and H2S. Microbial community and functional microbial analysis showed that the PN-Anammox and SADN processes were the main processes to achieve the conversion of pollutants in the scrubbing liquid.


Asunto(s)
Desnitrificación , Nitrificación , Procesos Autotróficos , Reactores Biológicos , Nitrógeno/análisis , Oxidación-Reducción , Azufre , Aguas Residuales
10.
Bioresour Technol ; 329: 124919, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676353

RESUMEN

Links between synergy and microbial community characteristics in co-digestion of food waste (FW), cattle manure (CM) and corn straw (CS) were investigated. Mono-digestion of FW and CS were inhibited by organic acids. Co-digestion of FW with CM achieved greater synergistic rates (18.5% and 22.3%) than CM with CS (14.8% and 12.3%). Synergy resulted from coupling effects of improving nutrient balance, dilution of toxic compounds, higher buffering capacity, detoxification based on co-metabolism, which ultimately reflected in microbial community functions. Although co-digestion of FW with CS exhibited lowest synergistic rates (7.9% and 4.9%), detoxification based on co-metabolism of syntrophic communities of Syntrophomonadaceae with hydrogenotrophic methanogens accelerated system recovery. Digester with the greatest synergy (65% FW + 35% CM) maintained dominant growth of hydrogenotrophic methanogens (68.9%), highest methanogenic community diversity and relative abundance of Methanosarcina (14.6%), which sustained more diverse and switchable methanogenic pathways therefore ensured powerful methanogenic functions and vigorous methanogenic capability.


Asunto(s)
Microbiota , Eliminación de Residuos , Anaerobiosis , Animales , Biocombustibles , Reactores Biológicos , Bovinos , Digestión , Alimentos , Estiércol , Metano , Zea mays
11.
Bioresour Technol ; 329: 124904, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676354

RESUMEN

An integration of two processes, magnetic coagulation (MC) and short-cut biological nitrogen removal (SBNR), coupled with a sequencing batch membrane bioreactor (SMBR) controlled by an automatic real-time control strategy (RTC), was developed to treat different characteristics of high strength wastewater. The treatment efficiency and microbial community-diversity of the proposed method was evaluated and investigated using swine wastewater and food waste (FW) digestate. The MC showed high removal of TSS (89.1 ± 1.5%, 92.21 ± 1.8%), turbidity (90.58 ± 2.1%, 95.1 ± 2.1%), TP (88.5 ± 1.9%, 92.1 ± 1.5%), phosphate (87.76 ± 1.6%, 91.22 ± 1.5%), and SMBR achieved stable and excellent removal of COD (96.05 ± 0.2%, 97.39 ± 0.2%), TN (97.30 ± 0.3%, 97.44 ± 0.3%) andNH4+-N (99.07 ± 0.2%, 98.54 ± 0.2%) for swine wastewater and FW digestate, respectively. The effluent COD andNH4+-N concentrations were found to meet their discharge standards. The microbial community comparison showed similar diversity and richness, and genus Diaphorobacter and Thaurea were dominant in denitritation, and Nitrosomonas was dominant in nitritation treating both swine wastewater and FW digestate.


Asunto(s)
Eliminación de Residuos , Aguas Residuales , Animales , Reactores Biológicos , Desnitrificación , Alimentos , Fenómenos Magnéticos , Nitrógeno , Porcinos , Eliminación de Residuos Líquidos
12.
Bioresour Technol ; 329: 124920, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33677423

RESUMEN

Hydroxylamine (NH2OH), one of the most important intermediates of anammox was employed to test the recovery performance because of its stimulation to anammox bacteria. Batch test indicated simultaneous addition of 1.83 ~ 9.17 mg N /L NH2OH relieved Cr(VI) inhibition because of extracellular reduction to Cr(III). The recovery efficiency (RE) was over 166%, with the effluent Cr(VI) and Cr(III) below 0.25 and 0.12 mg/L, respectively. Anammox activity after Cr(VI) inhibition was effectively recovered by 8 mg N/L NH2OH with RE at 218%. The long-term operation showed 1 ~ 2 mg N/L NH2OH accelerated the recover speed of nitrogen removal rate with 2.84 folds, as well as improving NH4+ conversion ratio and reducing NO3- production. After 55 days recovery, extracellular polymeric substance concentration, anammox activity and heme content recovered better with NH2OH addition. This study will provide the theoretical basis for rapid recovery of anammox activity by NH2OH when suffering Cr(VI) inhibition.


Asunto(s)
Matriz Extracelular de Sustancias Poliméricas , Nitrógeno , Reactores Biológicos , Cromo , Hidroxilamina , Hidroxilaminas , Oxidación-Reducción
13.
Bioresour Technol ; 329: 124918, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33684839

RESUMEN

Sulfur-driven autotrophic denitrification (SDAD) is feasible for the treatment of low-C/N-ratio and sulfur-laden wastewaters. The nitrite accumulated in SDAD will affect the performance and stability of the system but can be a potential electron acceptor. Thus, single- and multiple-electron acceptor-mediated SDAD systems were investigated. Batch assays revealed that nitrite and nitrate were the preferential options in the SDAD system with single and multiple electron acceptors, respectively. Synchronous nitrogen and sulfur removal was successfully achieved in continuous flow experiments with multiple electron acceptors, and the system could adapt well to high concentrations of sulfide, nitrate and nitrite (i.e., 720, 108 and 64.8 mg L-1, respectively), with the predominant genera shifting from Thiobacillus (48.88%) at the initial stage to unclassified_p_Firmicute (34.24%) and Syner-01 (12.31%) at the last stage. This work provides a fundamental basis for applying and regulating SDAD with multiple electron acceptors for the remediation of nitrogen- and sulfide- laden wastewaters.


Asunto(s)
Microbiota , Nitrógeno , Procesos Autotróficos , Reactores Biológicos , Desnitrificación , Electrones , Nitratos , Azufre
14.
Bioresour Technol ; 329: 124928, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33690060

RESUMEN

In current study, the enhancement effect of magnetite on anaerobic digestion was evaluated at increased organic loading rate (OLR) from 1.6 to 25.6 kg COD·m-3·d-1. The supplement of magnetite enhanced the methane yield by 7-483% accompanied with faster VFAs conversion. Microbial analysis suggested the varied enhancing effect achieved at different OLRs was attributed to different syntrophic interactions triggered by magnetite. More specially, an electroactive syntropy was established between Trichococcus with Methanobacterium at OLR lower than 6.4 kg COD·m-3·d-1, while with the OLR increase, more acid fermentative bacteria (Propionimicrobium, Syner-01) were enriched and further enhanced methanogenesis in a syntrophic way with Methanosaeta. Overall, the incorporation of magnetite was a promising approach to achieve efficient anaerobic digestion, OLR was also critical factor affecting the methanogenesis and should be carefully regulated in future application.


Asunto(s)
Reactores Biológicos , Microbiota , Anaerobiosis , Óxido Ferrosoférrico , Metano
15.
Bioresour Technol ; 329: 124927, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33706177

RESUMEN

The anaerobic digestion of leachate from organic fraction of municipal solid waste (OFMSW) is a long-standing challenge. A submerged anaerobic membrane bioreactor (AnMBR) embedding three flat sheet membrane was therefore continuously operated for 63 days to investigate the materials flow and membrane performance. The results obtained show that approximately 90% COD was removed and 86% was converted into methane under an OLR of 5.6 kgCOD/m3·d corresponding to a HRT of 10 days. Under the high solid condition (34.5-61.1 g/L total solids in AnMBR) and flux of 5 and 6 LMH, the membranes was operated practically at constant trans-membrane pressure (TMP). When the membrane was operated at a high flux of 7 LMH the TMP rapid increase occurred in 22 h resulting in a non-recoverable permeability. A sustainable flux was thus identified. This study demonstrated the feasibility of AnMBR treating OFMSW leachate under high solid condition with high flux.


Asunto(s)
Membranas Artificiales , Residuos Sólidos , Anaerobiosis , Reactores Biológicos , Metano , Eliminación de Residuos Líquidos
16.
Bioresour Technol ; 329: 124913, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33711716

RESUMEN

This study investigated the tolerance, defensive response and methanogenic pathways of anaerobic granular slugde and anaerobic suspended sludge (AGS and ASS) exposed to different LCM concentrations. AGS presented a higher tolerance to LCM stress, accompanied with 20.8 ± 2.6% enhancement in methane production at 1000 mg/L LCM, which was likely attributed to the less cell deaths and extracellular polymeric substances (EPSs) protection. In the acidification stage, acetate accumulation was stimulated and the activity of acetate kinase was promoted by LCM. In the methanogenesis stage, propionate and butyrate utilization for methane production were impaired after LCM addition. LCM also improved the activity of pyruvate-ferredoxin oxidoreductase and strengthened the process of hydrogenotrophic methanogenesis, likely by accelerating interspecies electron transfer mediated by hydrogen. ErmB and ermF were the dominate LCM resistance genes in AGS under LCM pressure conferring the resistance mechanism of ribosomal protection.


Asunto(s)
Biocombustibles , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Lincomicina , Metano
17.
Bioresour Technol ; 329: 124937, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33712339

RESUMEN

With the increasing popularity of waste to energy conversion, demand for large-scale operation of anaerobic digestors has emerged in the market. However, the process instabilities in anaerobic digestors limit the expansion of facilities to high loading rates. The irregularities in the process can be addressed directly by altering the feedstock characteristics provided an on-hand, robust, and sensitive monitoring device is available. In this context, the bioelectrochemical system has emerged as an excellent tool for monitoring and optimizing the anaerobic process within the reactor. This article reviews the gradual evolution in techniques and approaches for monitoring of anaerobic digestion (AD) process. An analysis of the recently popular biosensing techniques has been done with a focus on the bioelectrochemical monitoring system and its operation mode. A brief attempt to highlight the current challenges in the field of bioelectrochemical process monitoring for AD has also been made, which can be supportive of future research.


Asunto(s)
Reactores Biológicos , Metano , Anaerobiosis
18.
Bioresour Technol ; 329: 124917, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33714926

RESUMEN

Soluble chemical oxygen demand (SCOD) release by free nitrous acid (FNA)/NO2 system is usually called "FNA disintegration", despite lack of evidence that FNA is the main agent responsible for organic matter breakdown. The aim of this study was to investigate whether FNA or NO2 is the primary disintegration factor of thickened secondary sludge in a wide spectrum of process parameters (T = 48 h, 0-2280 mg NO2-N/L, pH 3.2-6.4 and FNA between 0 and 47.4 mg HNO2-N/L). Statistical analysis based on multiple regression and the Akaike Information Criterion showed that NO2, not FNA, is a main disintegrating factor leading to SCOD release (p = 0.005206 and 0.00009 respectively) and that the FNA concentration is without statistical significance (p = 0.800234 and 0.328099 respectively). These findings are important as understanding key factors is essential for productive future research and technology development. Moreover, these findings give doubts about the role of FNA in its other applications such as inhibition of nitrification.


Asunto(s)
Ácido Nitroso , Aguas del Alcantarillado , Reactores Biológicos , Nitrificación , Nitritos
19.
Bioresour Technol ; 329: 124916, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33730622

RESUMEN

Nanobubble technology has significant potential to improve the anaerobic digestion (AD) process by ameliorating the rate-limiting steps of hydrolysis and methanogenesis, as well as providing process stability by reducing sulfide and volatile fatty acid (VFA) levels. Nanobubbles (NB) can enhance substrate accessibility, digestibility, and enzymatic activity due to their minuscule size, high electrostatic interaction, and ability to generate reactive oxygen species. Air- and O2-NB can create a microaerobic environment for higher efficiency of the electron transport system, thereby reducing VFAs through enhanced facultative bacterial activity. Additionally, H2- and CO2-NB can improve hydrogenotrophic methanogenesis. Recently, several studies have employed NB technology in the AD process. There is, however, a lack of concise, synthesized information on NB applications to the AD process. This review provides an in-depth discussion on the NB-integrated AD process and the putative mechanisms involved. General discussions on other potential applications and future research directions are also provided.


Asunto(s)
Reactores Biológicos , Metano , Anaerobiosis , Ácidos Grasos Volátiles , Hidrólisis
20.
Bioresour Technol ; 330: 124965, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33735725

RESUMEN

With the increasing of data in wastewater treatment, data-driven machine learning models are useful for modeling biological processes and complex reactions. However, few data-driven models have been developed for simulating the microbial electrolysis cells (MECs) and traditional models are too ambiguous to comprehend the mechanisms. In this study, a new general data-driven two-stage model was firstly developed to predict CH4 production from in-situ biogas upgrading in the biocathode MECs via direct electron transfer (DET), named NARX-BP hybrid neural networks. Compared with traditional one-stage model, the model could well predict methane production via DET with excellent performance (all R2 and MES of 0.918 and 6.52 × 10-2, respectively) and reveal the mechanisms of biogas upgrading, for the new systematical modeling approach could improve the versatility and applicability by inputting significant intermediate variables. In addition, the model is generally available to support long-term prediction and optimal operation for anaerobic digestion or complex MEC systems.


Asunto(s)
Biocombustibles , Metano , Anaerobiosis , Reactores Biológicos , Electrólisis , Electrones , Aprendizaje Automático , Redes Neurales de la Computación
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