Enhanced amount and quality of alginate-like exopolysaccharides in aerobic granular sludge for the treatment of salty wastewater

Abstract

Osmotic pressure provided by salty wastewaters is an important influencing factor for alginate-like exopolysaccharides (ALE) in aerobic granular sludge (AGS). Therefore, research on the influence of salinity (NaCl 0 R1, 10 g/L R2, 30 g/L R3) on AGS and its ALE formation was conducted. A salinity of 1% induced larger particle size with smooth spheroidal shape and enhanced granular strength in R2. The TOC and ammonia removal were unaffected in both R2 and R3, but the P removal was greatly enhanced. ALE was much enriched at moderate salinity (1% NaCl). The amount of ALE reached 49.8 mg/g VSS at 140 d in R2, which was much higher than in R1 (26.8 mg/g VSS) and R3 (28.9 mg/g VSS), possibly due to the activation of gene algC expression in AGS of R2. ALE also showed the largest GG block fractionation and MW in R2, which indicated the greatest enhancement of mechanical properties. Moreover, enrichment of glucosamine, lipid content, and octadecanamide derivative in ALE of R2 endowed it with medicinal potential, stronger water-barrier property, and reduction of the products’ friction coefficients, respectively. Therefore, AGS based on ALE is a potential technology for treatment of salty wastewater.

Extraction, recovery and characterization of structural extracellular polymeric substances from anammox granular sludge

“…For practical industrial application, extraction and recovery of enough amount of EPS from sludge samples is the prerequisite. Aerobic granules yield a high ALE content of up to 330 mg/g VSS (Felz et al, 2016;Meng et al, 2019). As calculated, in the Netherlands, the recovered AGS-based ALE is anticipated to achieve 85 kton in the coming decade (Pronk et al, 2015;van Leeuwen et al, 2018).…”

Microbial Ecology of Granular Biofilm Technologies for Wastewater Treatment: A Review

“…In addition, they can be applied in soils for water retention. Algae , Pseudomonas , and Azotobacter are the main microorganisms implicated in ALE production [ 74 ]. On the other hand, PHA is a polyester used in the biofuels, packaging, and ink industries and the biomedicine sectors.…”

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

“…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.…”