Simplicispira sedimenti sp. nov., isolated from a sediment of drainage ditch in winery

A Gram-stain-negative, motile (by single polar flagellum) and rod-shaped bacterium, designated W1-6T, was isolated from a sediment of drainage ditch in winery in Guiyang, south-western China. Strain W1-6T showed the highest 16S rRNA gene sequence similarities with the type strain of Acidovorax wautersii (98.1%) and Simplicispira lacusdiani (97.9%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain W1-6T was placed adjacent to the members of the genus Simplicispira and formed a separat subclade. Cells showed oxidase and catalase negative reactions. The only respiratory quinone detected was ubiquinone-8 (Q-8). Summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0 and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) were predominant cellular fatty acids (> 10%) of strain W1-6T. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and five unidentified phospholipids were found in the polar lipid extraction. The genomic DNA G + C content was 65.6%. Strain W1-6T shared the highest digital DNA-DNA hybridization [dDDH, (27.6%)] and average nucleotide identity [ANI (84.3%)] values with the type strain of S. lacusdiani. The dDDH and ANI values were below the cutoff level (dDDH 70%; ANI 95-96%) for species delineation. The polyphasic characteristics indicated that the strain W1-6T represents a novel species of the genus Simplicispira, for which the name Simplicispira sedimenti sp. nov. is proposed. The type strain is W1-6T (= CGMCC 1.16274T = NBRC 115624T).

Microbial community origin and fate through a rural wastewater treatment plant

Conventional wastewater treatment relies on a complex microbiota; however, much of this community is still to be characterised. To better understand the origin, dynamics and fate of bacteria within a wastewater treatment plant: untreated primary wastewater, activated sludge, and post-treatment effluent were characterised. From 3,163 Exact Sequence Variants (ESVs), 860 were annotated to species-level. In primary wastewater, 28% of ESVs were putative bacterial species previously associated with humans, 14% with animals and 5% as common to the environment. Differential abundance analysis revealed significant relative reductions in ESVs from potentially humans-associated species from primary wastewater to activated sludge, and significant increases in ESVs from species associated with nutrient cycling. Between primary wastewater and effluent, 51% of ESVs from human-associated species did not significantly differ, and species such as Bacteroides massiliensis and Bacteroides dorei increased. These findings illustrate that activated sludge increased extracellular protease and urease-producing species, ammonia and nitrite oxidizers, denitrifiers and specific phosphorus accumulators. Although many human-associated species declined, some persisted in effluent, including strains of potential health or environmental concern. Species-level microbial assessment may be useful for understanding variation in wastewater treatment efficiency as well as for monitoring the release of microbes into surface water and the wider ecosystem. This article is protected by copyright. All rights reserved.

Biological recovery of phosphorus from waste activated sludge via alkaline fermentation and struvite biomineralization by Brevibacterium antiquum

Struvite biomineralization is a promising method for phosphorus recovery from wastewater treatment plant streams, and the growth of responsible microorganisms in mixed cultures is one of the most critical points for applying this process in pilot and full-scale. This study aimed to investigate the growth and bio-struvite production of Brevibacterium antiquum in mixed sludge culture. Alkaline fermentation was applied at different pH conditions to enhance the phosphorus content of sludge for an efficient recovery, and pH 8 was determined as the most feasible considering the phosphorus release and sludge characteristics. Growth optimization studies showed that NaCl's presence decreases the growth rate of Brevibacterium antiquum and bio-struvite production. At the same time, pH in the range of 6.8-8.2 did not alter the growth significantly. In addition, studies showed the ability of Brevibacterium antiquum in unsterilized fermented sludge centrate to grow and recover the phosphorus as struvite. Thus, our results indicated the potential of struvite biomineralization in full-scale wastewater treatment plants.

Enhanced nitrogen removal in an electrochemically coupled biochar-amended constructed wetland microcosms: The interactive effects of biochar and electrochemistry

The interactive effects of both biochar (BC) and electrochemistry (EC) can affect nitrogen (N) removal process. However, little is known about how this function in constructed wetland (CW) systems. In this study, an electrochemically (EC) coupled BC-amended saturated subsurface vertical flow constructed wetland (BECW) systems were established to enhance nitrogen (N) removal. Other three CW systems: without BC and EC (CW); with EC only (ECW); and with BC only (BCW) were performed as controls. Results indicated that the total nitrogen (59.88%-93.03%) and nitrate‑nitrogen (83.14%-100%) of the BECW system were significantly enhanced (p < 0.05) compared with the control systems. Treated WWTP tail-water could meet Class-IV of the Surface Water Quality Standard (GB3838-2002) in China by the BECW system. The enhanced N removal in the BECW system could be attributed to (1) the autotrophic denitrification process in which H₂ and Fe²⁺ provided by the cathode and anode acted as electron donors; and (2) BC addition acting as substrate could improve the activity, diversity and richness of microorganisms. Microbial community analysis further indicated that high N removal in the BECW system was significantly dependent on the synergy between the heterotrophic and autotrophic denitrifiers, facilitated by BC and EC interaction. Results illustrate that the BECW system is a feasible and eco-sustainable technology for treating low C/N tail-water from WWTPs. This work provides a novel and fundamental understanding of the electrochemically coupled biochar-amended CW system. These results could serve as a theoretical basis for the engineered applications in the deep purification of WWTPs' tail-water.

Treatment of low-strength ammonia wastewater by single-stage partial nitritation and anammox using upflow dual-bed gel-carrier reactor (UDGR)

This study investigated the single-stage partial nitritation and anammox (S-PNA) treatment of low-strength ammonia wastewater (≤140 mg NH₄⁺-N/L). Upflow dual-bed gel-carrier reactor (UDGR) with polyvinyl alcohol cryogel biocarriers, developed in this study, was employed for the anammox biomass enrichment from conventional activated sludge and subsequent S-PNA experiments. Anammox biomass was successfully enriched from conventional activated sludge. The enriched anammox carriers were inoculated together with gel carriers containing nitrifying sludge into the S-PNA reactors. S-PNA activity developed rapidly, and the nitrogen removal efficiency and rate reached up to 90.1% (with complete ammonia removal) and 0.15 kg N/m³⋅d, respectively, under low nitrogen loading conditions (0.10-0.17 kg N/m³⋅d). The microbial community structure changed significantly while adapting to anammox and S-PNA conditions. Anammox was likely driven solely by a Candidatus Jettenia population accounting for ≤49.4% of bacterial 16S rRNA genes. The results demonstrate that the UDGR-based S-PNA is suitable for treating low-strength wastewater.