Algaculture integration in conventional wastewater treatment plants: Anaerobic digestion comparison of primary and secondary sludge with microalgae biomass

Mahdy, Ahmed; Méndez, Lara; Ballesteros, Mercedes; González‐Fernández, Cristina

doi:10.1016/j.biortech.2014.09.145

Cited by 98 publications

(34 citation statements)

References 31 publications

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“…This strategy could be easily implemented in microalgal-based wastewater treatment plants (WWTPs), where harvested microalgal biomass could be co-digested with primary sludge from primary settlers. Indeed, primary sludge is more readily digestible and has less protein content than microalgae [ 15 ], so it could enhance microalgae biodegradability while increasing the OLR. To the best of our knowledge, only a few studies have evaluated the co-digestion of microalgae with primary sludge and always in batch tests [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Strategies to Optimize Microalgae Conversion to Biogas: Co-Digestion, Pretreatment and Hydraulic Retention Time

et al. 2018

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This study aims at optimizing the anaerobic digestion (AD) of biomass in microalgal-based wastewater treatment systems. It comprises the co-digestion of microalgae with primary sludge, the thermal pretreatment (75 °C for 10 h) of microalgae and the role of the hydraulic retention time (HRT) in anaerobic digesters. Initially, a batch test comparing different microalgae (untreated and pretreated) and primary sludge proportions showed how the co-digestion improved the AD kinetics. The highest methane yield was observed by adding 75% of primary sludge to pretreated microalgae (339 mL CH4/g VS). This condition was then investigated in mesophilic lab-scale reactors. The average methane yield was 0.46 L CH4/g VS, which represented a 2.9-fold increase compared to pretreated microalgae mono-digestion. Conversely, microalgae showed a low methane yield despite the thermal pretreatment (0.16 L CH4/g VS). Indeed, microscopic analysis confirmed the presence of microalgae species with resistant cell walls (i.e., Stigioclonium sp. and diatoms). In order to improve their anaerobic biodegradability, the HRT was increased from 20 to 30 days, which led to a 50% methane yield increase. Overall, microalgae AD was substantially improved by the co-digestion with primary sludge, even without pretreatment, and increasing the HRT enhanced the AD of microalgae with resistant cell walls.

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Section: Introductionmentioning

confidence: 99%

Strategies to Optimize Microalgae Conversion to Biogas: Co-Digestion, Pretreatment and Hydraulic Retention Time

et al. 2018

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“…Based on this idea, a number of works showing the possibility to repower sewage sludge digesters by using cosubstrates have been published recently. The proposed co-substrates include grass biomass (Hidaka et al, 2016; Abendroth et al, 2017), food waste (Zahan et al, 2016), municipal solid waste (Cabbai et al, 2016), glycerol (Jensen et al, 2014), microalgae (Mahdy et al, 2015), or pear residues (Arhoun et al, 2013). To make such repowering approaches applicable for the industry, and to meet the high standards of water treatment plants regarding process stability, a better understanding of the microbial changes ocurring during the transition from typical sewage digestion to high-load digestion processes is still needed.…”

Section: Introductionmentioning

confidence: 99%

Liquid co-substrates repower sewage microbiomes

Hardegen¹,

Latorre‐Pérez²,

Vilanova³

et al. 2018

Preprint

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A range of parameters are known to shape the methanogenic communities of biogas-producing digesters and to strongly influence the amount of biogas produced. In this work, liquid and solid fractions of grass biomass were used separately for semicontinuous batch methanation using sewage sludge as seed sludge. During 6 months of incubation, the amount of input COD was increased gradually, and the underlying methanogenic microbiome was assessed by means of microscopy-based automated cell counting and full-length 16S rRNA high-throughput sequencing. In this sense, we prove for the first time the suitability of the ONT TM MinION platform as a monitoring tool for anaerobic digestion systems. According to our results, solid-fed batches were highly unstable at higher COD input concentrations, and kept Methanosaeta spp. -typically associated to sewage sludge-as the majoritary methanogenic archaea. In contrast, liquid-fed batches developed a more stable microbiome, and proved enriched in Methanosarcina spp. This work demonstrates the high repowering potential of microbiomes from sewage sludge digesters, and highlight the effectiveness of liquefied substrates for anaerobic digestions.

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“…In recent literature the emissions of GHG from the conventional configurations of WWTPs were determined but the analysis of the possible alternatives to minimize these emissions is generally not done [24][25][26][27][28]. On the other hand, most of the papers studying the application of new processes to remove pollutants from wastewaters are mainly focused on the energy savings [29][30][31][32] and only few of them also give an environmental evaluation [33][34][35][36]. Therefore, the main objective of this work is to provide an overview of all possible ways to reduce GHG emissions from WWTPs.…”

Section: Introductionmentioning

confidence: 99%

Greenhouse Gases Emissions from Wastewater Treatment Plants: Minimization, Treatment, and Prevention

Campos

Valenzuela-Heredia

Pedrouso

et al. 2016

Journal of Chemistry

114

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The operation of wastewater treatment plants results in direct emissions, from the biological processes, of greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as indirect emissions resulting from energy generation. In this study, three possible ways to reduce these emissions are discussed and analyzed:(1)minimization through the change of operational conditions,(2)treatment of the gaseous streams, and(3)prevention by applying new configurations and processes to remove both organic matter and pollutants. In current WWTPs, to modify the operational conditions of existing units reveals itself as possibly the most economical way to decrease N2O and CO2emissions without deterioration of effluent quality. Nowadays the treatment of the gaseous streams containing the GHG seems to be a not suitable option due to the high capital costs of systems involved to capture and clean them. The change of WWTP configuration by using microalgae or partial nitritation-Anammox processes to remove ammonia from wastewater, instead of conventional nitrification-denitrification processes, can significantly reduce the GHG emissions and the energy consumed. However, the area required in the case of microalgae systems and the current lack of information about stability of partial nitritation-Anammox processes operating in the main stream of the WWTP are factors to be considered.

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Algaculture integration in conventional wastewater treatment plants: Anaerobic digestion comparison of primary and secondary sludge with microalgae biomass

Cited by 98 publications

References 31 publications

Strategies to Optimize Microalgae Conversion to Biogas: Co-Digestion, Pretreatment and Hydraulic Retention Time

Strategies to Optimize Microalgae Conversion to Biogas: Co-Digestion, Pretreatment and Hydraulic Retention Time

Liquid co-substrates repower sewage microbiomes

Greenhouse Gases Emissions from Wastewater Treatment Plants: Minimization, Treatment, and Prevention

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