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1.
Water Environ Res ; 2021 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-33657245

RESUMEN

Fe(II) is one of the commonly used additives in wastewater treatment and proved to be beneficial for promoting microbial activity. In this study, the effects of Fe(II) on the specific anammox activity (SAA) and reactor performance were proved to be concentration-dependent. In the short-term experiment, low concentration of Fe(II) (5-80 mg/L) significantly enhanced the SAA, while high concentration of Fe(II) (120-300 mg/L) inhibited the SAA. It was confirmed that anammox can be domesticated after long-term exposure to low Fe(II) concentration, and the SAA could be further enhanced by higher Fe(II) concentration in the following phases. In addition, as an important factor for anammox granulation and maintaining the SAA, the extracellular polymeric substance (EPS) was also affected by Fe(II) addition. In spite of the effects on SAA and EPS, Fe(II) was proved to be the key factor that enhances the N2 O emission via abiotic pathway in the anammox reactor. PRACTITIONER POINTS: Low Fe(II) concentrations enhanced SAA, while high concentrations inhibited SAA. Long-term acclimatization by Fe(II) improved the tolerance of anammox to Fe(II). Fe(II) affects the amount and constituent of EPS and the performance of anammox granules. Accumulation of Fe(II) in the AAFEB reactor promoted the N2 O emission.

2.
Bioresour Technol ; 330: 124961, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33735727

RESUMEN

The performance stability and its recovery mechanisms of a partial nitritation-anammox process were investigated. A one-stage airlift enhanced micro-granules (AEM) system was operated for 650 days continuously to treat 50 mg-NH4/L wastewater. During the stable stage, a high nitrogen removal efficiency of 72.7 ± 8.4% lasting for 230 days was successfully achieved under 0.28 L/min aeration rate and 0.10-0.20 mg/L dissolved oxygen (DO) concentration. A microbial consortium with good granularity appeared in red. The specific activity of anammox and ammonia oxidation increased to 1.02 and 0.93 g-N/g-VSS/d, respectively. Meanwhile, the microbial analysis showed the AEM system shifted the dominant microflora from Proteobacteria to Planctomycetes in which Candidatus Brocadia abundance reached a high of 35.0%. The results reveal that the long-term airlift-aeration promoted granulation and further enhanced activities, the abundances of anammox bacteria, and suppressed nitrite-oxidizing bacteria. Optimizing the DO control is also critical for stability increment and process recovery.


Asunto(s)
Compuestos de Amonio , Reactores Biológicos , Bacterias , Nitritos , Nitrógeno , Oxidación-Reducción , Aguas Residuales
3.
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
4.
Sci Total Environ ; 775: 145799, 2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-33621884

RESUMEN

A 20 L hollow-fiber submerged anaerobic membrane bioreactor (SAnMBR) was used to treat real domestic wastewater at 25 °C with hydraulic retention times (HRTs) ranging from 4 to 12 h. The process performance was evaluated by organic removal efficiency, biogas production, sludge yield, and filtration behaviors during one-year's operation. For HRTs ranging between 6 and 12 h, the AnMBR showed good organic removal efficiency with chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal efficiencies of about 89% and 93%, respectively. The biogas yield was 0.26 L-gas/g-CODfed, with approximately 80% methane content, and the sludge yield was 0.07-0.11 g-VSS/g-CODrem. While at an HRT of 4 h, with the higher wastewater treatment capacity and organic loading rate (OLR), the biogas production was lower (0.17 L-gas/g-CODfed), and the sludge production was higher (0.22 g-VSS/g-CODrem). The organic removal performance (COD 84% and BOD 89%) at HRT of 4 h was acceptable due to the effective separation effect of the membrane filtration process. According to COD balance analysis, the low biogas yield and high sludge yield at HRT of 4 h were due to insufficient biodegradation under an OLR of 2.05 g-COD/L-reactor/d. Theoretical calculations based on Henry's law indicate that the ideal methane content in the biogas should be 82-85% when the operational temperature was 25 °C. To achieve a high flux and sustainable AnMBR operation, the impact of mixed liquor suspended solid (MLSS) and gas sparging velocity (GSV) on the filtration performance was analyzed. The critical flux increased with increase in the GSV from 24.2 to 174.3 m/h, but decreased with increase in the MLSS concentration from 8.2 to 20.2 g/L. Therefore, decreasing fouling rate to 0.8-1.2 kPa/d by efficiently controlling GSV and MLSS, sustainable operation could be achieved at a flux of 0.34 m/d.


Asunto(s)
Eliminación de Residuos Líquidos , Purificación del Agua , Anaerobiosis , Reactores Biológicos , Membranas Artificiales , Metano , Aguas del Alcantarillado , Temperatura , Aguas Residuales
5.
Water Res ; 193: 116861, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33548693

RESUMEN

The potential of the formation of anammox-hydroxyapatite (HAP) granule composites as a cost-effective approach to removing nitrogen and phosphorus in the treatment of wastewater has been recently reported. Before these annamox granules, which consist of an anammox biofilm layer and an HAP crystallizing layer, can be used in applications, the formation mechanism of hydroxyapatite (HAP) encapsulation in the granules needs to be further studied. In this work, the role of extracellular polymeric substance (EPS) secreted by microorganisms and HAP core in Ca and P removal in anammox-HAP coupled granular sludge was investigated. According to the Lamer model, it is possible that the nucleation time of the granules becomes shorter as the crystal seeds. The enhanced buffering capacity of the granules was 0.08 mmol-H+ SS-g-1 with the pH kept above 6.5 for a comfortable environment for anammox. The results of this study show that ion competition and exchange, mainly between cations of Ca2+ and Mg2+ and between anions of PO43- and CO32-, affects the precipitation process. The results of this study indicate that the addition of granule crystal seeds can be used as a strategy to hasten the anammox process, and therefore accelerate the overall process.


Asunto(s)
Reactores Biológicos , Aguas del Alcantarillado , Durapatita , Matriz Extracelular de Sustancias Poliméricas , Nitrógeno , Oxidación-Reducción
6.
Bioresour Technol ; 326: 124754, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33524883

RESUMEN

To support smart city in terms of municipal waste management and bioenergy recovery, a high-solid anaerobic membrane bioreactor (AnMBR) was developed for sewage sludge (SeS) and food waste (FW) treatment in this study. COD mass balance showed that 54.1%, 66.9%, 73.5%, 91.4% and 93.5% of the COD input was converted into methane at the FW ratio of 0, 25%, 50%, 75% and 100%, respectively. The corresponding net energy balance was 13.6, 14.1, 17.1, 22.9 and 27.4 kJ/g-VS, respectively. An important finding of this investigation was that, for the first time, the relationship between net energy balance and carbon to nitrogen (C/N) ratio was revealed and the established sigmoid-type function was shown to be capable of predicting energy balance at different C/N ratios regardless of the region. The outcomes of this study show the potential of high-solid AnMBRs in SeS and FW treatment for supporting smart cities in the future.


Asunto(s)
Eliminación de Residuos , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Digestión , Alimentos , Metano , Eliminación de Residuos Líquidos
7.
Bioresour Technol ; 326: 124781, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33540215

RESUMEN

Poor processing stability has been cited as the fatal shortcoming of the up-flow anaerobic sludge blanket (UASB) reactor treating starch wastewater (SW). In this study, the SW treatment performance in a one-stage UASB reactor and a pre-acidification equipped UASB process were evaluated together with the microbial dynamics. The results revealed that the pre-acidification provided improvements in terms of the substrate utilization diversity and the stability of the microbial community structure on the UASB reactor. Anaerolineaceae/Methanosaeta was the core functional microbiota in the pre-acidification equipped UASB reactor, indicated the superior abilities on the acetogenic methanogenesis of granules. The genus of Methanobacterium, a hydrogenotrophic methanogen was dominant in the archaeal community in the one-stage UASB reactor. The granules performed very strong hydrogen affinity in methane production, a small amount of propionate was detected in the effluent. These were abnormal, which suggested the high hydrogen turn-over rate in the one-stage UASB reactor.


Asunto(s)
Microbiota , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Concentración de Iones de Hidrógeno , Metano , Almidón , Eliminación de Residuos Líquidos , Aguas Residuales
8.
Bioresour Technol ; 324: 124668, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33453520

RESUMEN

A one-stage airlift internal circulation biofilm reactor was continuously operated for 668 days to treat 50 mg/L of ammonia wastewater to pursue the long-term stability of partial nitritation and anammox (PNA) process. The operational performance and microbial community structure of the biofilm and the flocs were investigated. A nitrogen removal efficiency (NRE) of 70% was obtained successfully at a dissolved oxygen (DO) of 0.05-0.15 mg/L by regulating aeration rate. The microbial analysis indicated Candidatus Brocadia (29.5%) and Nitrosomonas (6.8%) were dominant in both biofilms and flocs. It was found that DO control and aeration rate were the key factors in performance stability, and a stable performance could be recovered and maintained under oxygen-limiting conditions. Further, the achievement of activated ammonia oxidation bacteria (AOB), dominated anammox bacteria (AMX), suppressed NOB, and controlled heterotrophic bacteria (HB) in the biofilms played a major role in the long-term stable operation.


Asunto(s)
Compuestos de Amonio , Microbiota , Amoníaco , Biopelículas , Reactores Biológicos , Nitrógeno , Oxidación-Reducción
9.
Bioresour Technol ; 319: 124123, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32971330

RESUMEN

The aim of this work was to demonstrate the operation of a large pilot-scale submerged anaerobic membrane bioreactor (5.0 m3) for biogas production from municipal wastewater at ambient temperature of 25 °C. To the best of our knowledge, this is the largest one-stage submerged AnMBR that has ever been reported. This AnMBR realized a hydraulic retention time (HRT) of 6 h and a treatment capacity of 20 m3 d-1, obtaining excellent effluent quality with COD removal efficiency over 90% and BOD5 removal over 95%. The biogas yield of the AnMBR was 0.25-0.27 L g-1 removed COD and 0.09-0.10 L L-1 raw wastewater. The methane content of the biogas was at the range of 75%-81%. The COD and nitrogen mass balance were also identified based on long-term operation. The hollow-fiber membrane module realized a flux of 2.75-17.83 LMH. An online backwash chemical cleaning system helped to lower the transmembrane pressure timely.


Asunto(s)
Biocombustibles , Aguas Residuales , Anaerobiosis , Reactores Biológicos , Membranas Artificiales , Metano , Eliminación de Residuos Líquidos
10.
Bioresour Technol ; 319: 124144, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32979595

RESUMEN

Domestic wastewater (DWW) can be preconcentrated to facilitate energy recovery via anaerobic digestion (AD), following the concept of "carbon capture-anaerobic conversion-bioenergy utilization." Herein, real DWW and preconcentrated domestic wastewater (PDWW) were both subject to particle size fractionation (0.45-2000 µm). DWW is a type of low-strength wastewater (average COD of 440.26 mg/L), wherein 60% of the COD is attributed to the substances with particle size greater than 0.45 µm. Proteins, polysaccharides, and lipids are the major DWW components. PDWW with a high COD concentration of 2125.89 ± 273.71 mg/L was obtained by the dynamic membrane filtration (DMF) process. PDWW shows larger proportions of settleable and suspended fractions, and accounted for 63.4% and 33.8% of the particle size distribution, and 52.4% and 32.2% of the COD, respectively. The acceptable biomethane potential of 262.52 ± 11.86 mL CH4/g COD of PDWW indicates bioenergy recovery is feasible based on DWW preconcentration and AD.


Asunto(s)
Eliminación de Residuos Líquidos , Aguas Residuales , Anaerobiosis , Bioensayo , Reactores Biológicos , Fraccionamiento Químico , Tamaño de la Partícula
11.
Water Res ; 188: 116522, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33091802

RESUMEN

The increasing pressure on the global water supply calls for more advanced solutions with higher efficiency and better sustainability, leading to the promptly developing water reclamation and reuse schemes including treatment technologies and risk management strategies where microbial safety is becoming a crucial aspect in the interest of public health. Backed up by the development of membrane technology, membrane bioreactors (MBR) have received substantial attention for their superiority over conventional treatment methods in many ways and are considered promising in the water reclamation realm. This review paper provides an overview of the efforts made to manage and control the potential waterborne viral disease risks raised by the use of effluent from MBR treatment processes, including the mechanisms involved in the virus removal process and the attempts to model the dynamics of the removal process. In principle, generalized and integrated virus removal models that provide insight into real-time monitoring are urgently needed for advanced real-time control purpose. Future studies of approaches that can well handle the inherent uncertainty and nonlinearity of the complex removal process are crucial to the development and promotion of related technologies.


Asunto(s)
Membranas Artificiales , Purificación del Agua , Reactores Biológicos , Membranas , Eliminación de Residuos Líquidos , Agua
12.
Sci Total Environ ; : 143526, 2020 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-33288248

RESUMEN

Sludge yield and suspended solid are important factors concerned in the anaerobic treatment of municipal wastewater. In this study, a large pilot-scale anaerobic membrane bioreactor (AnMBR) was constructed for effectively treating real municipal wastewater at an ambient temperature of 25 °C. The sludge yield and the degradation of influent suspended solids were evaluated during the long-term operation of the AnMBR. This reactor with 5.0 m3 effective volume is the largest one-stage submerged AnMBR that has ever been used to treat municipal wastewater. During the long-term operation of 217 days, this AnMBR obtained excellent COD and BOD5 removal efficiency over 90%. Stable biogas production was also successfully obtained from treating municipal wastewater. The sludge yield of the AnMBR was approximately 0.19-0.26 g MLSS g-1 COD removed for the treatment of real municipal wastewater. The shortest SRT of the AnMBR was calculated as 29 days for an HRT of 6 h at an empirical MLSS of 10 g L-1. While the influent suspended solid (SS) contained in the municipal wastewater was completely removed by the AnMBR, only 57%-66% of the influent SS was degraded. The rest of influent SS was directly converted to MLSS instead of being degraded. The AnMBR maintained a stable membrane filtration using a hollow-fiber membrane with a total area of 72 m2, realizing a flux of 2.75-17.83 LMH, and the mean transmembrane pressure (TMP) was 0.9-23.5 kPa. An online chemical backwash cleaning system helped to lower the TMP timely using sodium hypochlorite and citric acid when the TMP increased rapidly and reached the rated limit of membrane. This is the first report on demonstrating the successful operation and detailed performance of a large pilot-scale AnMBR applied to the treatment of real municipal wastewater.

13.
Bioresour Technol ; 321: 124432, 2020 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-33260065

RESUMEN

A novel internal circulation contact oxidation membrane bioreactor (ICCOMBR) was constructed to investigate a three steps startup strategy of single-stage partial nitritation-anammox (SPNA) system. A stable nitrite accumulation rate (NAR) of 86.60% was achieved with NH4+-N over 250 mg/L in nitritation process. The partial nitritation process could be effectively achieved by reducing the aeration rate (AR) by about 50% in the nitritation process, with an effluent NO2--N/NH4+-N ratio of 1.15 ± 0.04. The SPNA system was started up in 27 days following the inoculated anammox granular sludge. A total nitrogen removal efficiencies of 82% was achieved at a NLR of 0.60 gN/L/d and dissolved oxygen (DO) concentration below 0.55 mg/L. Anammox function genus (Ca.Kuenenia and Ca. Anammoximicrobium) abundance accounted for 20.77% in the biofilm, which is approximately equal to 22.2% in the suspended sludge. Nitrosomon as the dominant AOB genera, was detected in the biofilm (6.5%) and suspended sludge (13.3%).

14.
Bioresour Technol ; 320(Pt A): 124342, 2020 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-33157439

RESUMEN

This study used an intermittent self-agitation anaerobic baffled reactor (SA-ABR) to treat food waste. The organic matter and detailed composition evolution were analyzed under continuous operation. The gas production rate was 2.43 ± 0.18 L-Gas/d/L-Re, and the biogas conversion was 0.94 L-Gas/g-TS. The effluent concentration of total chemical oxygen demand (COD) was 22.5 ± 2.44 g/L, and the removal rate of soluble COD was always over 97%. In this study, the removal rates of carbohydrate, protein, and lipids in the SA-ABR treatment were 95%, 60%, and 85%, respectively, and the concentrations were 0.11 g/L, 0.32 g/L, and 0.33 g/L, respectively. The conversion of soluble organic matter was much higher than that of insoluble substrates. The concentration of soluble pollutants was significantly lower than that of pollutants in suspended matter. The treatment of organic matter in the first half of the SA-ABR was 85-100% that of the entire reactor.

15.
Sci Total Environ ; : 142551, 2020 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-33092842

RESUMEN

The feasibility of in-situ stabilization in the co-digestion of coffee grounds (CG) and waste activated sludge (WAS) was investigated. Two lab-scale thermophilic continuous stirred tank reactors (CSTR), R1 and R2 were operated with substrates that contained different WAS ratios, S1 (WAS% = 20%) and S2 (WAS% = 30%). During the whole process, there was no external supply of ammonia and trace elements. The volatile solid (VS) removal efficiency of R1 and R2 was comparable, and the biogas yield of R1 (0.467 ± 0.100 L/g-VSin) was slightly higher than R2 (0.408 ± 0.020 L/g-VSin). The total ammonia nitrogen (TAN) of R1 and R2 was 482 ± 32 and 884 ± 24 mg/L, respectively. The stoichiometry formulas of co-digestion were established to calculate the theoretical microbial yield coefficients and the requirements of microorganism reproduction. A comparison between the theoretical requirements and experimental values showed that co-digestion with WAS could avoid supply for an external supply of minerals. For the net energy production, R1 and R2 could generate 6342 and 5069 kWh of electricity daily, respectively.

16.
J Hazard Mater ; : 124183, 2020 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-33092879

RESUMEN

The roles of biochar and granular activated carbon (GAC) in the enhancement of anaerobic phenol degradation were characterized through batch tests conducted at different phenol concentrations, coupled with adsorption kinetics, microbial community, and in-situ electrochemical analysis. Both biochar and GAC (15 g/L) led to markedly shorter lag times (t0) by adsorbing dissolved phenol, and faster maximum CH4 production rate (Rmax) by triggering direct interspecies electron transfer (DIET) during a two-stage (adsorption then degradation) anaerobic phenol degradation. The high adsorption capacity of GAC helped achieve a shorter t0, but less affected Rmax of subsequent phenol degradation. Compared with GAC, which showed higher conductivity but no redox activity, biochar exhibited higher electron exchange capacity (6.57 µmol e-/g). This higher electron exchange capacity stemmed from the diverse redox-active moieties, which resulted in a more efficient DIET. Meanwhile, the formation of wire-like appendages which linked the enriched DIET partners (such as Syntrophorhabdus and Methanosaeta) on biochar probably futher enhanced the electron transfer. However, hydrogenotrophic methanogenesis was still the main pathway for syntrophic phenol degradation in the suspended sludge. The in-situ analysis also confirmed that biochar and GAC acted as geobatteries and geoconductors, respectively, and that the stimulation of DIET was persistent.

17.
Water Res ; 187: 116436, 2020 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-32977189

RESUMEN

Disposal of the increasingly huge amounts of sewage sludge (SeS) has become an impending problem worldwide. To solve this problem, a high-solid anaerobic membrane bioreactor (AnMBR) was used for the anaerobic co-digestion (AcoD) of SeS and food waste (FW). This study investigated the effects of SeS ratio on the methanogenic performance of the AcoD with a gradual increase value from 0 to 25%, 50%, 75% and 100% (total solids based). The results showed that the highest methanogenic performance was achieved at mono FW digestion. As for the co-digestion, the optimal FW/SeS ratio for methanogenic performance was 75%:25% among all the mixing ratios. The COD based biogas yield and methane yield were 0.498 L-biogas/g-CODfed and 0.295 L-CH4/g-CODfed at this optimal mixing ratio, which were 67.7% and 67.6% higher than those of the mono SeS digestion, respectively. The upgraded values were attributed to the improved hydrolysis ratio (by 8.14%) and the balanced carbon-to-nitrogen (C/N) ratio by co-digestion with FW, which synergistically stimulated methanogenesis ratio by 81.0%. The continuous membrane filtration property was investigated and four typical trans-membrane pressure (TMP) variation curves at different fouling degrees were determined. The membrane could sustainably operate at a flux of 6 L/m2/h (LMH) at the mixed liquor total solids (MLTS) concentration of 25 - 30 g/L. The combination of continuous membrane filtration property, particle size distribution of the mixed liquor and the external forces analysis was firstly applied to unravel the membrane fouling mechanism of a high-solid AnMBR. The result of this study will contribute to the establishment of an efficient FW and SeS treatment strategy.

18.
Water Res ; 187: 116444, 2020 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-32992148

RESUMEN

For digestion effluent treatment, while the anammox-based process has been successfully applied for nitrogen removal, in most cases, phosphorus (P) represents another major concern. In this study, a novel process, integrating the partial nitritation/anammox and hydroxyapatite crystallization (PNA-HAP) in a single airlift reactor, was developed for the simultaneous nitrogen removal and P recovery from synthetic digestion effluent. With a stable influent P concentration of 20.0 mg/L, an HRT of 6 h, and alternating increases of influent calcium and ammonium, the final achieved nitrogen removal rate was 1.2 kg/m3/d and the P removal efficiency was 83.0%. The settleability of sludge was desirably enhanced with the calcium addition and a high biomass concentration was achieved in reactor. Quantitative and qualitative analyses confirmed that HAP was the main inorganic content in sludge, which could be harvested for P recovery. According to the Scanning Electron Microscope observation and the Energy Dispersive X-ray spectrometry analysis, the microbes were mainly distributed on the outer layer of the sludge aggregate, while the HAP mainly in the interior. The relevant theoretical calculation also revealed that the sludge discharge manipulation has direct effect on the sludge composition and aggregate structure. In sum, the results are evidence of the feasibility of simultaneous nitrogen removal and P recovery through one-stage PNA-HAP process for digestion effluent.

19.
Water Sci Technol ; 82(2): 292-302, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32941171

RESUMEN

Duckweed biomass production in a duckweed pond fed with three differently treated sewage (i.e. sewage treated by primary sedimentation (PS); conventional activated sludge process (CAS); and downflow hanging sponge process (DHS)) was evaluated in order to assess the effects of water quality on biomass yield. Higher and stable biomass production was observed when the duckweed pond was fed with PS or DHS-effluent than with CAS-effluent, evidently due to the difference in nutrient loads. Availability of nutrients, especially phosphorus, affected the biomass production rate: higher the nutrient, faster the production. Microbial community analysis revealed that the members of Rhizobiales were likely to contribute to stable and high biomass growth. From the results of the study, a sewage treatment system consisting of a primary sedimentation followed by a duckweed pond and a tertiary treatment unit can be proposed to maximize biomass production without compromising treatment objectives. Size and operational parameters of the duckweed pond should be determined primarily based on the nutrient availability in the influent water to maximize duckweed growth.


Asunto(s)
Araceae , Microbiota , Biomasa , Estanques , Aguas del Alcantarillado , Eliminación de Residuos Líquidos
20.
J Hazard Mater ; 399: 123098, 2020 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-32937719

RESUMEN

To study the inhibited degradation metabolism and anaerobic digestion of typical lipids in food waste, an artificially produced capsaicin, N-Vanillylnonanamide, a typical soluble component in waste lipids, was added to a glycerol trioleate anaerobic digestion system. The microorganisms damage and blocked electron transfer caused by N-Vanillylnonanamide during anaerobic digestion were further clarified. Scanning electron microscopy and transmission electron microscopy images demonstrated that N-Vanillylnonanamide (≥4 wt%) structurally damaged microorganisms via cell membrane breakage, which impair their function. N-Vanillylnonanamide inhibited the activities of the key enzyme CoA, AK, F420, and CoM, which are relevant for both degradation metabolism and anaerobic digestion. 16S rRNA analysis showed that dominant bacterial and archaeal communities markedly decreased after anaerobic digestion of glycerol trioleate with N-Vanillylnonanamide (≥4 wt%). For example, the proportion of Methanosarcina decreased from 30 % to 6 %. Current-voltage curves indicated that the electron transfer rate in the community of microorganisms decreased by 99 % from 4.67 × 10-2 to 5.66 × 10-4 s-1 in response to N-Vanillylnonanamide (40 wt%). The methane yield during anaerobic digestion of glycerol trioleate decreased by 84.0 % from 780.21-142.10 mL/g-total volatile solids with N-Vanillylnonanamide (40 wt%).

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