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1.
Water Res ; 174: 115629, 2020 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-32113013

RESUMEN

A novel technique for phosphorus recovery from the liquid phase of anaerobic digestate was developed using biochar derived from iron-rich sludge (dewatered sludge conditioned with Fenton's reagent). The biochar pyrolyzed from iron-rich sludge at a low temperature of 300 °C (referred to as Fe-300 biochar) showed a better phosphorus (P) adsorption capacity (most of orthophosphate and pyrophosphate) than biochars pyrolyzed at other higher temperatures of 500-900 °C, with the maximum P adsorption capacity of up to 1.843 mg g-1 for the liquid phase of anaerobic digestate. Adsorption isotherms study indicated that 70% P was precipitated through chemical reaction with Fe elements, i.e., Fe(II) and Fe(III) existed on the surface of the Fe-300 biochar, and other 30% was through surface physical adsorption as simulated by a dual Langmuir-Langmuir model using the potassium dihydrogen orthophosphate (KH2PO4) as a model solution. The seed germination rate was increased up to 92% with the addition of Fe-300 biochar after adsorbing most of P, compared with 66% without the addition of biochar. Moreover, P adsorbed by the chemical reaction in form of iron hydrogen phosphate can be solubilized by a phosphate-solubilizing microorganism of Pseudomonas aeruginosa, with the total solubilized P amount of 3.045 mg g-1 at the end of an incubation of 20 days. This study indicated that the iron-rich sludge-derived biochar could be used as a novel and beneficial functional material for P recovery from the liquid phase of anaerobic digestate. The recovered P with biochar can be re-utilized in garden soil as an efficient P-fertilizer, thus increasing the added values of both the liquid phase of anaerobic digestate and the iron-rich sludge.


Asunto(s)
Fósforo , Aguas del Alcantarillado , Adsorción , Anaerobiosis , Carbón Orgánico , Compuestos Férricos , Fertilizantes , Hierro
2.
Bioresour Technol ; 304: 123021, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32086031

RESUMEN

The present study aimed to enhance the biomethanation potential of mixed microalgae via cost effective surfactant coupled ultrasonic homogenization (SCUH). Mixed microalgae biomass was harvested using a coagulant (Alum) from a raceway pond. The harvested algal biomass was subjected to ultrasonic homogenization (UH) by varying the power from 100 to 180 W. A maximal soluble organic release of 2131 mg/L was achieved at an ultrasonic input energy (UIE) of 25200 kJ/kg TS. In order to enhance soluble organic release and to reduce energy spent, the optimized condition of ultrasonic pretreatment was coupled with varying sodium dodecyl sulphate (SDS) dosage. A higher solubilization of 30.5% was achieved at a UIE of 4200 kJ/kg SS with surfactant dosage of 0.02 g SDS/g SS for SCUH. SCUH showed higher methane production of 358 mL/g COD when compared to UH (185.9 mL/g COD), SCUH was economically feasible than UH.


Asunto(s)
Microalgas , Anaerobiosis , Biomasa , Metano , Estanques , Tensoactivos , Ultrasonido
3.
Bioresour Technol ; 304: 123004, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32087544

RESUMEN

Intermittent supply of easily degradable carbohydrates can be used for on-demand biogas production. The study tested the effects of splitting feeding portions of sugar beet silage (S) on biogas production rates and total yield, respectively and if methane production rates follow those ones of biogas. Four experimental AD reactors were operated for 117 days at organic loading rates of 2.0 kgVS m-3 d-1 and VS ratios of maize silage (M) to S of 3:1. While M was supplied hourly (h0-h12), reactors differed only regarding the intermittent S supply, provided at once (h0), twice (h0, h1) and three times (h0, h1, h2) per twelve-hour observation period. Biogas and methane production rates rose simultaneously after S supply and lasted depending on S intakes. Biogas and methane yields were significantly increased at S given once and twice per period. Appropriate feedstock management can thus influence production rates and increase biogas and methane yields.


Asunto(s)
Biocombustibles , Reactores Biológicos , Anaerobiosis , Metano , Ensilaje
4.
Bioresour Technol ; 304: 122981, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32088624

RESUMEN

Anaerobic high-solid treatment (HST) for processing food waste and biogas production is a viable technology with considerable commercial potential. In this study, we examined and compared mesophilic and thermophilic industrial-scale plug-flow digesters. The HSTs demonstrated reasonable biogas yields from food waste (0.4-0.6 Nm3 CH4/kg volatile solids). However, during operation at thermophilic conditions ammonia inhibition (~2 g NH3-N/L) and acid accumulation (6-14 g/L) caused severe process disturbance. Microbial community structures diverged between the processes, with temperature appearing to be a strong driver. A unique feature of the thermophilic HSTs was high abundance of the uncultivated Clostridia group MBA03 and temperature fluctuations in one mesophilic HST were linked to drastically decreased abundance of methanogens and relative abundance of Cloacimonetes. The process data obtained in this study clearly demonstrate both potential and challenges in HST of food waste but also possibilities for management approaches to tackle process imbalance and restore process function.


Asunto(s)
Biocombustibles , Eliminación de Residuos , Anaerobiosis , Reactores Biológicos , Alimentos , Metano
5.
Bioresour Technol ; 304: 123000, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32088625

RESUMEN

An increasing interest is devoted to combined microbial electrolysis cell-anaerobic digestion (MEC-AD) system which could convert waste activated sludge into biogas. In this study series tests were initially conducted to study the effect of alkaline pretreatment on AD system and the results showed that alkaline pretreatment could promote the dissolution of organic matters in the sludge and thus improve the methane production. Then, the methane production in combined MEC-AD system fed with alkaline-pretreated sludge was investigated. The results indicated that the methane productions increased by 37% and 42% when applied voltage was 0.5 V and 0.8 V. The microbial electrochemical system strongly promoted the growth of Euryarchaeota (Methanosaeta and Methanobacterium). Meanwhile, the abundance of Paraclostridium increased from 17.9% to 38.5% when applied voltage was 0.8 V, suggesting an enhanced fermentation and acetogenesis process. The results of energy balance estimation indicated that MEC-AD system at 0.5 V could achieve higher net energy output.


Asunto(s)
Reactores Biológicos , Aguas del Alcantarillado , Anaerobiosis , Electrólisis , Metano , Eliminación de Residuos Líquidos
6.
Bioresour Technol ; 304: 122738, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32106021

RESUMEN

In this study, the performance of UASB for treating food waste leachate was investigated, with the objective of studying the effect of conductive material on anaerobic digestion (AD) enhancement at two organic loads. Conductive and control materials (i.e. graphite and glass) were first compared for their surface porosity then dosed in UASB for side-by-side comparison of the corresponding AD performance. In the first phase (organic load of 2660 mg-COD/L), compared to glass-added UASB, 29.5% reduction of effluent COD was observed in graphite-added UASB, however, only a little biogas enhancement (2.3%) was achieved. In the second phase (organic load of 4140 mg-COD/L), the results show that it could promote better AD enhancement in graphite-added UASB, where 36% effluent COD and 38% biogas production enhancement were simultaneously observed. The overall results support that utilization of conductive material is a viable approach for enhancing biogas production in UASB, especially for high organic loads.


Asunto(s)
Eliminación de Residuos , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Alimentos , Eliminación de Residuos Líquidos
7.
Bioresour Technol ; 304: 122998, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32107151

RESUMEN

Several feedstocks for anaerobic digestion (AD) have challenges that hamper the success of AD with their low accessible surface area, biomass recalcitrance, and the presence of natural inhibitors. This paper presents different types of pretreatment to address those individual challenges and how they contribute to facilitate AD. Organosolv and ionic liquid pretreatments are effective to remove lignin without a significant defect on lignin structures. To deal with accessible surface area and crystallinity, comminution, steam explosion, pretreatment using N-methyl-morpholine-N-oxide methods are suggested. Moreover, solid extraction, simple aeration, and biological treatments are capable in removing natural inhibitors. Up to date, methods like comminution, thermal process, and grinding are more preferable to be scaled-up.


Asunto(s)
Lignina , Vapor , Anaerobiosis , Biocombustibles , Biomasa
8.
J Environ Manage ; 260: 110160, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32090847

RESUMEN

This study investigated the effects of mineral waste extracts (MWE) on laboratory-scale two-stage anaerobic digesters treating synthetic organic waste. MWE was prepared as aqueous extracts from different ash samples (incineration bottom ash (IBA), fly ash (FA) and boiler ash (BA) taken from a municipal solid waste incineration plant. At 20 days hydraulic retention time, all three MWE stimulated hydrogen production in their respective acidogenic reactor by around 35% (c.f. control acidogenic reactor), whilst no difference was seen in the methane productivity of the linked methanogenic reactors (average 527 ± 45 mL CH4/g VS, including control methanogenic reactor). Following a step reduction in hydraulic retention time from 20 to 10 days and a doubling of the organic loading rate from 2.5 g to 5 g VS/L. d, no significant change was seen in hydrogen production (p > 0.05) in the acidogenic reactor amended with MWE from IBA and BA, or the control acidogenic reactor. However, the acidogenic reactor receiving MWE from FA had 45% lower hydrogen productivity. The step change in hydraulic retention time and organic loading rates led to the failure of most methanogenic reactors (≤100 mL CH4/g VS), however, the one receiving feed containing MWE from IBA showed stable performance without signs of failure, and had higher volumetric methane productivity, albeit at lower methane yields (370 ± 20 mL CH4/g VS). 16S rRNA analysis using the Illumina sequencing platform revealed acidogenesis by Lactobacillaceae in the acidogenic reactor and syntrophic acetate oxidation by Synergistaceae linked to enrichment of the candidatus genus Methanofastidiosum, in the stable methanogenic reactor receiving MWE from IBA.


Asunto(s)
Incineración , Residuos Sólidos , Anaerobiosis , Reactores Biológicos , Metano , Extractos Vegetales , ARN Ribosómico 16S
9.
World J Microbiol Biotechnol ; 36(2): 29, 2020 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-32016527

RESUMEN

Short-chain halogenated aliphatic hydrocarbons (e.g. perchloroethene, trichloroethene) are among the most toxic environmental pollutants. Perchloroethene and trichloroethene can be dechlorinated to non-toxic ethene through reductive dechlorination by Dehalococcoides sp. Bioaugmentation, applying cultures containing organohalide-respiring microorganisms, is a possible technique to remediate sites contaminated with chlorinated ethenes. Application of site specific inocula is an efficient alternative solution. Our aim was to develop site specific dechlorinating microbial inocula by enriching microbial consortia from groundwater contaminated with trichloroethene using microcosm experiments containing clay mineral as solid phase. Our main goal was to develop fast and reliable method to produce large amount (100 L) of bioactive agent with anaerobic fermentation technology. Polyphasic approach has been applied to monitor the effectiveness of dechlorination during the transfer process from bench-scale (500 mL) to industrial-scale (100 L). Gas chromatography measurement and T-RFLP (Terminal Restriction Fragment Length Polymorphism) revealed that the serial subculture of the enrichments shortened the time-course of the complete dechlorination of trichloroethene to ethene and altered the composition of bacterial communities. Complete dechlorination was observed in enrichments with significant abundance of Dehalococcoides sp. cultivated at 8 °C. Consortia incubated in fermenters at 18 °C accelerated the conversion of TCE to ethene by 7-14 days. Members of the enrichments belong to the phyla Bacteroidetes, Chloroflexi, Proteobacteria and Firmicutes. According to the operational taxonomic units, main differences between the composition of the enrichment incubated at 8 °C and 18 °C occurred with relative abundance of acetogenic and fermentative species. In addition to the temperature, the site-specific origin of the microbial communities and the solid phase applied during the fermentation technique contributed to the development of a unique microbial composition.


Asunto(s)
Anaerobiosis/fisiología , Bacterias/metabolismo , Biodegradación Ambiental , Arcilla/química , Microbiota/fisiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bacteroidetes/genética , Bacteroidetes/metabolismo , Chloroflexi/genética , Chloroflexi/metabolismo , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Fermentación , Firmicutes/genética , Firmicutes/metabolismo , Geobacter/genética , Geobacter/metabolismo , Agua Subterránea/microbiología , Consorcios Microbianos , Polimorfismo de Longitud del Fragmento de Restricción , Proteobacteria/genética , Proteobacteria/metabolismo , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/aislamiento & purificación , Tricloroetileno/química , Microbiología del Agua , Contaminantes Químicos del Agua/metabolismo
10.
Bioresour Technol ; 304: 122938, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32062393

RESUMEN

Extracellular DNA (exDNA) can induce bias when evaluating the microbiota in wastewater treatment systems, particularly when cell lysis caused by thermal hydrolysis pretreatment (THP) releasing abundant DNA. However, the influence of such exDNA is still unknown. Accordingly, this study applied a pretreatment strategy for DNA extraction with proteinase K and DNase Ⅰ to minimize the influence of exDNA when evaluating the sludge microbiota. Lactobacillus and Peptostreptococcus were confirmed as the main THP-resistant microorganisms. Gram-positive bacteria were more resistant to THP, implying that the presence of a cell wall could promote THP resistance in bacteria. Moreover, the ability to form spores did not affect the resistance of bacteria to THP. These findings showed that resistant microbiota could be effectively evaluated by excluding exDNA, which can provide important insights into the understanding of microbiota dynamic and the effects of pretreatment on the precision of microbiota analysis in sludge.


Asunto(s)
Microbiota , Eliminación de Residuos Líquidos , Anaerobiosis , ADN , Hidrólisis , Aguas del Alcantarillado
11.
Bioresour Technol ; 304: 123005, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32070840

RESUMEN

Petrochemical wastewaters treatment represents a serious challenge due to the high toxicity and complex chemical components. In this study, the biodegradability, mineralization behaviors and methane productivity of eight different types of petrochemical wastewaters were evaluated in series of semi-continuous bioreactors. Methane production strongly depended on the characteristics of wastewaters and chemical constituents. The highest methane yield of 305.9 ± 2.7 mL/g-COD was achieved by purified terephthalic acid wastewater, followed by ethylene glycol, polyester, etc. Comparatively, one-step-SCN- wastewater produced the lowest methane yield (4.7 ± 0.7 mL/g-COD) owing to high toxicity and low biodegradability. Modified Gompertz model confirmed that purified terephthalic acid, ethylene glycol and polyester wastewaters had a short lag-phase of 1.2, 1.7 and 0.2 days, respectively. Nonetheless, the formation of by-products such as proteins, polysaccharides and ammonia nitrogen throughout anaerobic digestion reflected the high activity of anaerobic microorganisms, confirming the technical feasibility of anaerobic biotechnology in treating petrochemical wastewaters.


Asunto(s)
Reactores Biológicos , Aguas Residuales , Amoníaco , Anaerobiosis , Metano
12.
Bioresour Technol ; 304: 122979, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32078902

RESUMEN

Semi-continuous experiments were conducted to compare the performances and energy efficiencies of two advanced anaerobic digestions (AAD) of sewage sludge with high-temperature thermal pretreatment (HTTP, 160 ± 1 °C and 0.55 MPa for 30 min) and low-temperature thermal-alkaline pretreatment (LTTAP, 60 ± 1 °C and pH 12.0 ± 0.1 for 30 min), which had similar sludge disintegration degree (9.44-9.48%). At the steady period of a SRT 20 d, the two AAD had similar methane production (150.22 ± 9.55 ml/L/d and 151.02 ± 12.56 ml/L/d) and organic matter removals (22.54 ± 2.84% and 23.15 ± 2.46% for volatile solids-VS). The results of high-throughput sequencing showed that the methanogenic pathways of the two AAD were strictly hydrogenotrophic (AAD with HTTP) and hydrogenotrophic/acetoclastic methanogenesis (AAD with LTTAP), respectively. The energy balance analysis suggested that the AAD with LTTAP was superior to that with HTTP because the former had a higher energy efficiency (1.610) than the latter (1.358).


Asunto(s)
Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Anaerobiosis , Metano , Temperatura Ambiental
13.
Bioresour Technol ; 304: 123006, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32078903

RESUMEN

Free nitrous acid based pretreatments are novel and effective chemical strategies for enhancing waste activated sludge solubilization. In this study, the synergetic effects of the combined free nitrous acid and electrochemical pretreatment on sludge solubilization and subsequent methane productivity were evaluated. The results indicated that pretreatment with 10 V plus 14.17 mg N/L substantially enhanced sludge solubilization, with the highest soluble chemical oxygen demand concentration of 3296.7 mg/L, 25.6-time higher than that without pretreatment (128.9 mg/L). Due to the potential toxicity of NO2- and NO3- to microorganisms and its bioprocesses, the methane production of sludge pretreated by free nitrous acid was significantly deteriorated. The maximum methane yield (152.0 ± 9.6 mL/g-VSadded) was observed at 10 V pretreatment alone, only 1.7% higher than that of the control (149.4 ± 1.6 mL/g-VSadded). Combined pretreatment indeed enhances the sludge solubilization and hydrolysis, but does not always induce an improved anaerobic digestion efficiency.


Asunto(s)
Ácido Nitroso , Aguas del Alcantarillado , Anaerobiosis , Hidrólisis , Metano , Eliminación de Residuos Líquidos
14.
Bioresour Technol ; 304: 122989, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32078905

RESUMEN

This study aimed to evaluate the effects and explore the mechanisms of polyethylene (PE), polyurethane sponge (PUS), and granule activated carbon (GAC) on short-chain fatty acids (SCFAs) production from sludge anaerobic fermentation. Results showed that no matter the biocarrier type, addition of biocarriers increased the diversity of SCFAs. In contrast with GAC, addition of PE and PUS considerably facilitated the accumulation of the total SCFAs. Suspended PE and PUS might have stronger frictions with sludge particles which resulted in a better sludge disintegration. Other factors that contributed to the enhancement of PE and PUS include higher hydrolytic and acidogenic enzymes activities, lower methanogenic enzyme activity, more Firmicutes and less Proteobacteria. Consistent with enzymatic and microbial results, the PE and the PUS tests also showed greater abundance in all metabolic functions predicted with PICRUSt. This study provides a novel strategy for sludge anaerobic fermentation by using traditional wastewater biocarriers.


Asunto(s)
Ácidos Grasos Volátiles , Aguas del Alcantarillado , Anaerobiosis , Fermentación , Concentración de Iones de Hidrógeno , Hidrólisis
15.
Bioresour Technol ; 304: 123016, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32078907

RESUMEN

The effects of four conductive nanomaterials (nano-carbon powder, nano-Al2O3, nano-ZnO, nano-CuO) on sludge anaerobic digestion (AD) performance and microbial community were investigated through a 36-day fermentation experiment. Results showed that biogas production enhanced by 16.9% and 23.4% with nano-carbon powder and nano-Al2O3 added but decreased by 90.2% and 17.3% with nano-ZnO and nano-CuO. Total solids (TS) removal efficiency was increased by 38.73% and 27.11% with nano-carbon powder and nano-Al2O3 added but decreased by 70.67% and 43.70% with nano-ZnO and nano-CuO. Kinetic analysis indicated four conductive nanomaterials could shorten the lag phase of AD sludge with an average rate of 51.75%. 16S rRNA amplicon sequencing results demonstrated microbes such as Syntrophomonas and Methanosaeta were enriched in nano-carbon powder and nano-Al2O3 reactors. However, microbial community diversity and richness were both inhibited by adding nano-ZnO and nano-CuO. Redundancy analysis (RDA) revealed that genera belong to Firmicutes and Chloroflexi could conduce to methanogenesis process.


Asunto(s)
Microbiota , Nanoestructuras , Anaerobiosis , Reactores Biológicos , Cinética , Metano , ARN Ribosómico 16S , Aguas del Alcantarillado
16.
Bioresour Technol ; 302: 122801, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32004811

RESUMEN

To provide insight into direct interspecies electron transfer (DIET) via carbon-based materials and ferric oxides, the effects of three conductive materials (i.e. activated carbon (AC), iron modified activated carbon (FEAC) and goethite (FEOOH)), on methanogenesis from volatile fatty acids (VFAs) were evaluated. Under the acid stress (~4 g/L VFAs), the maximum methane yield of 266 mL/g-chemical oxygen demand (COD) was found in the FEOOH supplemented reactor, which was 48% higher than that of AC reactor. The reasons for the enhanced activity of the electron transport chain and extracellular electron transfer ability by FEOOH include: 1) the activation on iron-containing enzymes that involved in methanogenesis and acidogenesis; 2) selective enrichment on functional microorganism. The higher electron donating capacities (EDC) value of FEOOH may be a triggering factor on the growth of Syntrophomonadaceae, which perform DIET with methanogens (Methanosaeta and Methanosarcina) for the syntrophic degradation of VFAs.


Asunto(s)
Carbón Orgánico , Methanosarcina , Anaerobiosis , Transporte de Electrón , Ácidos Grasos Volátiles , Compuestos de Hierro , Metano , Minerales
17.
Bioresour Technol ; 302: 122865, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32004814

RESUMEN

Fermentative caproate production from wastewater is attractive but is currently limited by the low product purity and concentration. In this work, continuous, selective production of caproate from acetate and ethanol, the common products of wastewater anaerobic fermentation, was achieved in an anaerobic membrane bioreactor (AnMBR). The reactor was continuously operated for over 522 days without need for chemical cleaning. With an ethanol-to-acetate ratio of 3.0, the effluent caproate concentration was 2.62 g/L on average and the caproate ratio in liquid products reached 74%. Further raising the influent ethanol content slightly increased the effluent caproate level but lowered the product selectivity and resulted in microbial inhibition. The Clostridia (the major caproate-producing bacteria) and Methanobacterium species (which consume hydrogen to alleviate microbial inhibition) was significantly enriched in the acclimated sludge. Our results imply a great potential of utilizing AnMBR to recover caproate from the effluent of wastewater acidogenic fermentation process.


Asunto(s)
Reactores Biológicos , Caproatos , Anaerobiosis , Bacterias Anaerobias , Fermentación
18.
Bioresour Technol ; 302: 122869, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32006928

RESUMEN

This study investigated the association of volatile fatty acid (VFA) production with microbial mechanism in waste activated sludge (WAS) anaerobic acidogenesis enhanced by freezing/thawing (F/T) pretreatment. WAS solubilization was enhanced with 955.4 ± 10.0 mg/L soluble chemical oxygen demand (SCOD) release by a 50-h F/T pretreatment at -24 °C. The highest level of VFAs (4852 ± 156 mg COD/L) was obtained after a 12-day fermentation. Moreover, phyla of Proteobacteria, Bacteroidetes, Firmicutes, and Ignavibacteriae played vital roles in VFA generation, while high genera abundance of Clostridium, Macellibacteroides, Prevotella, and Megasphaera were positively associated with high yields of short-chain (C2-C5) fatty acids. A schematic diagram was drawn to illustrate the microbial mechanism of enhanced VFA generation by F/T pretreatment during WAS fermentation. This study provides an in-depth exploration of promoting bio-resource recycling from WAS with a low-cost approach (specially in high latitudes) and bring about some new thinking on future WAS management.


Asunto(s)
Ácidos Grasos Volátiles , Aguas del Alcantarillado , Anaerobiosis , Fermentación , Congelación , Concentración de Iones de Hidrógeno
19.
Bioresour Technol ; 302: 122805, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32007847

RESUMEN

Anaerobic membrane bioreactor (AnMBR) is an advanced technology in treating pharmaceutical wastewater, but the membrane fouling limits its development. In this study, the biochar with adsorption capacity of biopolymers was added in AnMBR to investigate its potential in treating pharmaceutical wastewater and alleviating membrane fouling. In the biochar-amended AnMBR, adsorbable organic halogen (AOX) was removed effectively, and more COD was biotransformed into CH4. Membrane fouling mitigation was achieved in the third stage with a 56% decrease of average transmembrane pressure difference (TMP) rising rate. The predominant culprit, proteins of extracellular polymeric substance (EPS-proteins) in sludge mixture and cake layer, was reduced significantly. Particularly, the proportion of micromolecular (0.1-0.15 kDa) EPS-proteins in cake layer was 1.5-folds that of the control group. The important bio-foulant genus Arcobacter aggregating on the membrane had less and almost half the relative abundance (16.5%) than that of the control group (30.7%).


Asunto(s)
Matriz Extracelular de Sustancias Poliméricas , Aguas Residuales , Anaerobiosis , Reactores Biológicos , Carbón Orgánico , Membranas Artificiales , Aguas del Alcantarillado
20.
Bioresour Technol ; 302: 122851, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32007850

RESUMEN

This study involved a comparison between mesophilic (MAD) and thermophilic anaerobic digestion (TAD) of municipal sludge with high (10%) solids content; the reactor performance and the response of total and active microbial communities to changes in sludge properties were monitored. Both TAD and MAD were stably maintained. TAD performed better than MAD in biogas production and volatile total solids reduction upon feeding sludge 1. TAD was slightly inhibited by ammonia, whereas the performance of MAD was improved when sludge 2 was used as the feedstock. Alpha- and beta-diversity analyses revealed significant differences in the microbial community based on DNA and RNA datasets, indicating that not all microbes function in AD. The active microbial community diversity and composition in MAD and TAD were also driven by sludge properties. Moreover, MAD showed significantly higher richness and diversity of the active microbial community compared with TAD, regardless of changes in sludge properties.


Asunto(s)
Microbiota , Aguas del Alcantarillado , Amoníaco , Anaerobiosis , Biocombustibles , Reactores Biológicos , Metano
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