Research

14 pages, 12161 KiB

Open AccessArticle

Oxygen Uptake Rate as an Indicator of the Substrates Utilized by Candidatus Accumulibacter

by Alexander Dorofeev, Anna Pelevina, Yuri Nikolaev, Yulia Berestovskaya, Evgeny Gruzdev, Andrey Mardanov and Nikolai Pimenov

Water 2023, 15(20), 3657; https://doi.org/10.3390/w15203657 - 18 Oct 2023

Viewed by 1096

Abstract

Candidatus Accumulibacter belongs to phosphate-accumulating organisms (PAOs) which exhibit a cyclic metabolism and are capable of intracellular polyphosphate accumulation and their hydrolysis under feast-famine anaerobic-aerobic cycling. In consortia of activated sludge microorganisms, these bacteria are responsible for enhanced biological phosphorus removal (EBPR). The [...] Read more.

Candidatus Accumulibacter belongs to phosphate-accumulating organisms (PAOs) which exhibit a cyclic metabolism and are capable of intracellular polyphosphate accumulation and their hydrolysis under feast-famine anaerobic-aerobic cycling. In consortia of activated sludge microorganisms, these bacteria are responsible for enhanced biological phosphorus removal (EBPR). The spectrum of the substrates used by Ca. Accumulibacter remains insufficiently studied. It was investigated by measuring the oxygen uptake rates (OUR) of Ca. Accumulibacter-enriched culture supplemented with 17 different organic substrates. The highest oxygen uptake rate values were observed in the presence of tryptone, volatile fatty acids (acetate, propionate, and butyrate), succinate, pyruvate, and amino acids (aspartate and glutamate). Phosphate dynamics in the medium under shifts from anaerobic to aerobic cultivation in batch experiments were studied for these compounds (except for tryptone). All tested substrates were shown to cause phosphate cycling (release in the anaerobic phase and uptake in the aerobic one), with OURs for the substrates correlating with the number of phosphates consumed during the aerobic phase. It was concluded that OUR may be used as an indicator of the monosubstrates used by Ca. Accumulibacter in the anaerobic/aerobic cycle. The possible pathways for substrate transport and metabolism by Ca. Accumulibacter are discussed using stoichiometric data and the results of metagenomic analysis. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

18 pages, 2672 KiB

Open AccessArticle

Fault Detection of Wastewater Treatment Plants Based on an Improved Kernel Extreme Learning Machine Method

by Meng Zhou, Yinyue Zhang, Jing Wang, Tonglai Xue, Zhe Dong and Weifeng Zhai

Water 2023, 15(11), 2079; https://doi.org/10.3390/w15112079 - 30 May 2023

Cited by 3 | Viewed by 1306

Abstract

In order to ensure the stable operation, improve efficiency, and enhance sustainability of wastewater treatment systems, this paper investigates the fault detection problem in wastewater treatment process based on an improved kernel extreme learning machine method. Firstly, a kernel extreme learning machine (KELM) [...] Read more.

In order to ensure the stable operation, improve efficiency, and enhance sustainability of wastewater treatment systems, this paper investigates the fault detection problem in wastewater treatment process based on an improved kernel extreme learning machine method. Firstly, a kernel extreme learning machine (KELM) model optimized by an improved mutation bald eagle search (IMBES) optimizer is proposed to generate point predictions of effluent quality parameters. Then, based on the point prediction results, the confidence interval of effluent quality parameters is calculated using kernel density estimation (KDE) method. This interval represents the bounds of system uncertainty and unknown disturbance at normal conditions and can be treated as the threshold for fault diagnosis. Finally, the effectiveness of the proposed method is illustrated by two datasets obtained from the BSM1 wastewater simulation platform and an actual water platform. Experimental results show that compared with other methods such as CNN, LSTM, and IBES-LSSVM, this method has a significant improvement in prediction accuracy, and at the same confidence level, it ensures fault detection rate while generating smaller confidence intervals. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

20 pages, 7749 KiB

Open AccessArticle

Knowledge Mapping of High-Rate Algal Ponds Research

by Ming Li, Yang Wang, Jukui Zhang, Binshuo Liu, Honghai Xue, Lei Wu and Zhonghe Li

Water 2023, 15(10), 1916; https://doi.org/10.3390/w15101916 - 18 May 2023

Viewed by 1623

Abstract

High-rate algal ponds (HRAPs) are a highly promoted wastewater treatment system that uses sunlight as an energy source to provide the oxygen needed in the system through photosynthesis and has a high nutrient and organic matter removal capacity. In addition, the microalgae in [...] Read more.

High-rate algal ponds (HRAPs) are a highly promoted wastewater treatment system that uses sunlight as an energy source to provide the oxygen needed in the system through photosynthesis and has a high nutrient and organic matter removal capacity. In addition, the microalgae in the system can use wastewater as a growth substrate to produce valuable bioproducts, biomaterials, and bioenergy, so it is receiving more and more attention. This review uses bibliometric analysis to explore current research hotspots and future research trends in this emerging technology. By analyzing research papers related to HRAPs published in the Web of Science (WOS) from 1987 to 2021 based on the co-occurrence and clustering of keywords, it shows that the research hotspots of HRAPs are mainly focused on wastewater treatment, nutrient removal, microalgal biomass, biofuel, and biogas upgrading. In the future, in-depth research will continue to be added on the contribution of HRAPs to environmental sustainability, including E. coli removal, biogas upgrading and oxygen removal, treatment of aquaculture wastewater, purple phototrophic bacteria, aqueous biorefineries, and biorefineries. The results assist scholars in systematically understanding the current research status, research frontiers, and future trends of HRAPs from a macro perspective. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

11 pages, 1432 KiB

Open AccessArticle

How to Form Aggregates of Free Anammox Bacteria to Improve Sedimentation Performance

by Ni An, Yufeng Zheng, Yan Wei and Bin Ma

Water 2023, 15(10), 1836; https://doi.org/10.3390/w15101836 - 11 May 2023

Viewed by 1194

Abstract

Free anammox bacteria are superior in growth rate, but poor sedimentation performance limits their application in sewage treatment. In this study, we investigated how to form aggregates of free anammox bacteria to improve sedimentation performance. Calcium addition tests proved that free anammox bacteria [...] Read more.

Free anammox bacteria are superior in growth rate, but poor sedimentation performance limits their application in sewage treatment. In this study, we investigated how to form aggregates of free anammox bacteria to improve sedimentation performance. Calcium addition tests proved that free anammox bacteria could aggregate and form a larger entirety with better sedimentation performance through calcium cross-linking with alginate-like exopolysaccharides (ALEs). This was indicated by the particle size increasing by 411.45% and sedimentation performance (measured with supernatant transmittance) increasing by 195.35% after adding calcium for 12 h. Soluble extracellular polymeric substance (S-EPS) extraction and freeze–thaw testing elucidated that providing more cross-linking sites can strengthen the cross-linking, as indicated by the sedimentation performance increasing by 158.57% and 394.80%, respectively. Static experiments showed that cross-linking time was equally important. The sedimentation performance improved with longer static times under no severe external disturbances, with a 324.61% improvement after 84 h. However, the bacteria burst and the anammox activity disappeared after freeze–thaw treatment. Based on the above test results, a potential method for forming aggregates of free anammox bacteria to improve sedimentation performance was proposed: extract S-EPS with centrifugation first, add calcium, and keep the sludge free from external hydraulic interference. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

12 pages, 1843 KiB

Open AccessArticle

Partial Nitrification Characteristics of an Immobilized Carrier in Municipal Wastewater under Low-Temperature Shock: The Role of the Nitrifying Bacterial Community Structure

by Jiawei Wang, Lixinrui Yang, Yan Zhang, Haiping Zhang and Jiaju Liu

Water 2023, 15(9), 1714; https://doi.org/10.3390/w15091714 - 28 Apr 2023

Cited by 1 | Viewed by 1214

Abstract

To analyze the effects of the nitrifying bacterial community structure on the partial nitrification (PN) characteristics in a PN-immobilized carrier in municipal wastewater under low-temperature shock, two PN-immobilized carriers with different nitrifying bacterial communities were investigated. The E1-immobilized carrier contained a high abundance [...] Read more.

To analyze the effects of the nitrifying bacterial community structure on the partial nitrification (PN) characteristics in a PN-immobilized carrier in municipal wastewater under low-temperature shock, two PN-immobilized carriers with different nitrifying bacterial communities were investigated. The E1-immobilized carrier contained a high abundance of ammonia-oxidizing bacteria (AOB; 38.59%), and the E2-immobilized carrier had a low AOB abundance of 4.78%. The results of experiments with different dissolved oxygen (DO) concentrations showed that the oxygen-limited environment inside the immobilized carrier, generated by the high AOB abundance, was critical for achieving PN. The nitrite accumulation rate (NAR) decreased from 90.0–93.9% to 84.2–88.3% for the E1-immobilized carrier and from 86.0–90.4% to 81.7–85.8% for the E2-immobilized carrier under low-temperature shock (the temperature suddenly decreased from 25 ± 1 °C to 15 ± 1 °C). The decrease in the ammonia oxidation rate due to the decreased AOB activity led to a decrease in NAR. Moreover, NOB abundance in the E2-immobilized carrier increased because of the destruction of the oxygen-limiting region in the immobilized carrier due to the low AOB abundance. Increasing the abundance of AOB in the PN-immobilized carrier could reduce the adverse effects from the low-temperature shock. The results of this study can be used to further develop immobilization technology for efficient PN in mainstream wastewater treatment. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

13 pages, 2632 KiB

Open AccessArticle

Distribution of Antibiotic Resistance Genes and Their Association with Microbes in Wastewater Treatment Plants: A Metagenomics Analysis

by Mengnan Shen, Xiaowei Hu, Ming Li, Chen Lyu, Yi Hu, Xiaodan Bu, Tao Chen, Hang Cai, Chenyang Li, Jiahong Liu and Kai Fan

Water 2023, 15(8), 1587; https://doi.org/10.3390/w15081587 - 19 Apr 2023

Cited by 1 | Viewed by 1768

Abstract

The extensive use of antibiotics has resulted in the generation and accumulation of antibiotic resistance genes (ARGs) in the environment, and domestic wastewater is one of the main reservoirs of ARGs and resistant bacteria. In this study, Illumina high-throughput sequencing and network analysis [...] Read more.

The extensive use of antibiotics has resulted in the generation and accumulation of antibiotic resistance genes (ARGs) in the environment, and domestic wastewater is one of the main reservoirs of ARGs and resistant bacteria. In this study, Illumina high-throughput sequencing and network analysis were used to study the microbial community characteristics, ARGs’ occurrence status, and resistance mechanism in the influent and effluent of a domestic sewage treatment plant in Changchun, China. A total of 29 phyla were found in the influent and effluent, including 23 bacterial phyla, 3 archaeal phyla, and 3 eukaryotic phyla. In total, 112 ARG subtypes were detected in the samples, and the dominant ARG subtypes were Erm(35) and tet(W/N/W). In this study, ARGs related to tetracycline and macrolide accounted for a high proportion, and the resistance mechanisms of ARGs detected in the samples were mainly antibiotic inactivation and antibiotic efflux pumps. Co-occurrence maps of ARGs and microbes demonstrated by network analysis indicated that the resistance genes kdpE, GES-5, and tetX may easily bind to microbes, potentially making them antibiotic-resistant bacteria. Fifty-seven bacteria in the genera Cupriavidus, Escherichia, and Collinsell are potential hosts of multiple ARGs. The findings can increase our understanding of the distribution of ARGs and their association with microbes in wastewater treatment plants, and also provide a research foundation for controlling the diffusion of ARGs in the environment. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

12 pages, 1609 KiB

Open AccessArticle

Effect of Anammox Granular Sludge Type on the CANON Process with Immobilized Fillers Treating Domestic Wastewater

by Jiawei Wang, Shiliang Liu, Yan Zhang, Si Zhang and Jiaju Liu

Water 2023, 15(7), 1354; https://doi.org/10.3390/w15071354 - 01 Apr 2023

Cited by 2 | Viewed by 1382

Abstract

Immobilized fillers were prepared using intact and crushed ammonia oxidation granular sludge (AnGS) to compare their effects on the completely autotrophic N-removal over nitrite (CANON) process in domestic sewage. Using pre-aerated domestic sewage as an influent, the effect of granular type on nitrogen [...] Read more.

Immobilized fillers were prepared using intact and crushed ammonia oxidation granular sludge (AnGS) to compare their effects on the completely autotrophic N-removal over nitrite (CANON) process in domestic sewage. Using pre-aerated domestic sewage as an influent, the effect of granular type on nitrogen removal was investigated under intermittent aeration. The results show that the total nitrogen removal (TNR) of the crushed AnGS immobilized filler was 75.8–80.0% at a dissolved oxygen (DO) concentration of 3 mg/L, while the intact AnGS immobilized filler required a DO of 4 mg/L to achieve the same TNR level. The DO concentration is the key factor affecting the nitrogen removal efficiency, because partial nitrification was affected by the DO concentration. Candidatus Kuenenia was the dominant genus of anaerobic ammonium oxidation (anammox) bacteria, and its relative abundance was higher in the crushed AnGS immobilized filler (21.11%) than in the intact AnGS immobilized filler (9.60%). Furthermore, the immobilized filler could inhibit the growth of nitrite-oxidizing bacteria (NOB), and the relative abundance of Nitrospira, the major NOB genus, decreased after operation. The results of this study indicate that the use of AnGS immobilized filler is a promising strategy to strengthen the CANON process in municipal wastewater treatment. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

16 pages, 4725 KiB

Open AccessArticle

Study on Genomics of the Bisphenol A-Degrading Bacterium Pseudomonas sp. P1

by Shuaiguo Li, Kejian Tian, Qing Qiu, Yue Yu, Han Li, Menghan Chang, Xuejian Sun, Jinming Gu, Fenglin Zhang, Yibing Wang and Hongliang Huo

Water 2023, 15(4), 830; https://doi.org/10.3390/w15040830 - 20 Feb 2023

Cited by 2 | Viewed by 2214

Abstract

As a widespread pollutant, bisphenol A (BPA) has created a serious threat to ecosystem and human health. Therefore, expanding the available microbial resources used to screen highly efficient BPA-degrading bacteria with BPA as the sole carbon source is very important for the removal [...] Read more.

As a widespread pollutant, bisphenol A (BPA) has created a serious threat to ecosystem and human health. Therefore, expanding the available microbial resources used to screen highly efficient BPA-degrading bacteria with BPA as the sole carbon source is very important for the removal of this pollutant from the environment. In this study, the BPA degradation rate of Pseudomonas sp. P1 to 30 mg/L was 96.89% within 120 h. Whole genome sequencing showed that the genome of strain P1 was composed of a single circular chromosome with a full length of 6.17 Mb, which contained 5636 predicted coding genes. Comparative genomic analysis showed that strain P1 contained 210 functional genes related to BPA degradation. It was confirmed that BPA degradation genes ferredoxin (bisdA), P450 (bisdB), CotA and Lac in strain P1 were highly expressed under the induction of BPA. Combined with the identification of metabolites, the route of BPA degradation by Pseudomonas was proposed. A new metabolite, 4-vinylphenol, was detected for the first time in pathway Ⅰ. In pathway Ⅱ, BPA is directly oxidized to phenol and 4-isopropenyl phenol in the presence of laccase, which is rarely reported in the process of bacterial degradation of BPA. This study confirmed that strain P1 had good tolerance to various environmental factors at the gene level and enriched the degradation mechanism of BPA. Full article

(This article belongs to the Special Issue Functional Microorganisms in Wastewater Treatment)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Functional Microorganisms in Wastewater Treatment

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI