Properties of alginate-like exopolymers recovered from flocculent and granular microbial sludges of different biological treatment systems treating real municipal wastewater

Sarvajith, M.; Nancharaiah, Y.V.

doi:10.1016/j.seppur.2023.123460

Cited by 14 publications

(6 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ASE was always a minor component of EPSs as compared to ALE. The role of ALE is widely acknowledged during granulation to its abundance, and gelation properties (Sarvajith and Nancharaiah 2023). The granules collected on days 50 and 70 were less prone to disintegration by sonication as compared to the young granules (collected on days 20 and 30) (Supplementary Fig.…”

Section: Ags Formationmentioning

confidence: 99%

Using granular activated carbon for enhanced phosphate removal by aerobic granular sludge development with propionate as carbon source

Sarvajith,

Reddy,

Nancharaiah

2024

Preprint

View full text Add to dashboard Cite

Despite propionate being an important constituent of domestic wastewater, its effect on aerobic granular sludge (AGS) development and biological nutrient removal (BNR) pathways is not well studied. This study investigated the cultivation of AGS and establishment of BNR pathways using propionate as a sole carbon source in the bioreactors with and without granular activated carbon (GAC) particles. The presence of GAC particles reduced the start-up period for AGS formation and established of BNR pathways with propionate feeding. Aerobic granules were compact and had stable settling characteristics (≥ 1 mm, 6 g/L MLSS and 40 mL/g SVI). An increase in alginate-like exopolysaccharide (ALE) up to 400 mgALE/gSS corroborated with stable AGS formation. Stable and effective ammonium and total nitrogen removals were established by day 30. Ammonium was removed via simultaneous nitrification and denitrification as well as partial nitrification and denitritation pathways. Stable and efficient phosphorus removal was established from day 80. High phosphorus removals were corroborated with the abundance of polyphosphate accumulating organisms in the GAC biofilms. The GAC biofilms separated from the co-existing granules exhibited efficient phosphorus removal via enhanced bio-P removal. The high abundance of Thauera sp. in the GAC biofilms indicated its role in granulation and phosphorus removal under propionate feeding conditions.

show abstract

Section: Ags Formationmentioning

confidence: 99%

Using granular activated carbon for enhanced phosphate removal by aerobic granular sludge development with propionate as carbon source

Sarvajith,

Reddy,

Nancharaiah

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…These positive effects contributed to enhanced solid−liquid separation (Figure 1). Because alginate in St-EPS can be considered a gel-forming polysaccharide in WAS flocs, 15 the degradation of both ABF and St-EPS by enriched ADC may be crucial for breaking down the WAS structure and promoting dewatering. The WAS treated with ABF and enriched ADC exhibited a lower final St-EPS content than the control group, resulting in reduced viscosity and shear stress (Figure 4).…”

Section: Benefits Of Abf Utilization In Was Dewateringmentioning

confidence: 99%

“…(St-EPS), has been extracted from WAS flocs, typically comprising 10−30% of the total composition. 14,15 Owing to its nontoxicity and minimal secondary pollution, alginate has been used as a flocculant in wastewater treatment. 17 Alginate, a linear natural polymer, exhibits a strong affinity for multivalent metal ions (e.g., Ca 2+ and Mg 2+ ).…”

Section: Introductionmentioning

confidence: 99%

Deciphering the Dual Roles of an Alginate-Based Biodegradable Flocculant in Anaerobic Fermentation of Waste Activated Sludge: Dewaterability and Degradability

Wang,

Tang,

Ran

et al. 2024

Environ. Sci. Technol.

View full text Add to dashboard Cite

Biodegradable flocculants are rarely used in waste activated sludge (WAS) fermentation. This study introduces an alginate-based biodegradable flocculant (ABF) to enhance both the dewatering and degradation of WAS during its fermentation. Alginate was identified in structural extracellular polymeric substances (St-EPS) of WAS, with alginate-producing bacteria comprising ∼4.2% of the total bacterial population in WAS. Owing to its larger floc size, higher contact angle, and lower free energy resulting from the Lewis acid-base interaction, the addition of the prepared ABF with a network structure significantly improved the dewaterability of WAS and reduced capillary suction time (CST) by 72%. The utilization of ABF by an enriched alginate-degrading consortium (ADC) resulted in a 35.5% increase in the WAS methane yield owing to its higher hydrolytic activity on both ABF and St-EPS. Additionally, after a 30 day fermentation, CST decreased by 62% owing to the enhanced degradation of St-EPS (74.4%) and lower viscosity in the WAS + ABF + ADC group. The genus Bacteroides, comprising 12% of ADC, used alginate lyase (EC 4.2.2.3) and pectate lyase (EC 4.2.2.2 and EC 4.2.2.9) to degrade alginate and polygalacturonate in St-EPS, respectively. Therefore, this study introduces a new flocculant and elucidates its dual roles in enhancing both the dewaterability and degradability of WAS. These advancements improve WAS fermentation, resulting in higher methane production and lower CSTs.

show abstract

“…As of 2024, there are about 70 studies associating the EPS investigation with ALE extraction and characterization (search in Web of Science with keywords, sludge and alginate-like-). These studies covered a broad range of fields, including the production and functions of ALE in sludge, − as well as their chemical/physical properties and potential applications. ,− Among them, over 40 papers directly considered the ALE as exactly the same as alginates in the chemical composition.…”

Section: Introductionmentioning

confidence: 99%

“…Although ALE was frequently considered as alginates, until now there was hardly any direct evidence showing the presence of the two sugar monomers in the literature. Instead, analytical methods, such as colorimetric assays for total carbohydrates and proteins, spectroscopic techniques like Fourier transform infrared (FTIR), , and nuclear magnetic resonance (NMR) related to functional groups, along with fractionation by partial acid hydrolysis , and the hydrogel formation tests, ,, have been employed to characterize the ALE. Based on the results from these indirect analyses, conclusions about the resemblance to alginates were drawn.…”

Section: Introductionmentioning

confidence: 99%

Reinvestigating the Composition of Alginate-Like Exopolymers Extracted from Activated Sludge

Li,

Hao,

Persiani

et al. 2024

ACS EST Water

View full text Add to dashboard Cite

Over the past decade, a significant amount of research work on extracellular polymeric substances has been done on the "alginate-like exopolysaccharides" (ALE, also called "alginate-like exopolymers"). The term was used based on the FAO (Food and Agriculture Organization) biopolymer identification test. Although various chemical analyses have been conducted to characterize extracted ALE, it remained unclear whether ALE contains the two sugar monomers of alginates. Aiming to obtain a direct answer to the question: are there alginates in the ALE extracted from sludge, activated sludge was collected from two wastewater treatment plants in two different countries, where the ALE was previously extracted, characterized, and reported in the literature. The extracellular polymers were extracted from these sludges and fractionated according to the standard protocol. The sugar monomer composition of each fraction was analyzed, with special attention to the presence of mannuronic acid (M) and guluronic acid (G), which compose alginate biopolymers. None of these monomers were found in the extracted EPS, indicating there are no alginates resembling polymers extracted from the sludges. The possibility of the presence of other glycan components, such as lipopolysaccharides in EPS, was investigated and confirmed.

show abstract

Properties of alginate-like exopolymers recovered from flocculent and granular microbial sludges of different biological treatment systems treating real municipal wastewater

Cited by 14 publications

References 45 publications

Using granular activated carbon for enhanced phosphate removal by aerobic granular sludge development with propionate as carbon source

Using granular activated carbon for enhanced phosphate removal by aerobic granular sludge development with propionate as carbon source

Deciphering the Dual Roles of an Alginate-Based Biodegradable Flocculant in Anaerobic Fermentation of Waste Activated Sludge: Dewaterability and Degradability

Reinvestigating the Composition of Alginate-Like Exopolymers Extracted from Activated Sludge

Contact Info

Product

Resources

About