Bacteria In Wastewater Treatment Research Articles

Elucidating the potential of nitrifying bacteria in mitigating nitrogen pollution and its industrial application

Nitrifying bacteria are specialized microorganisms that actively participate in the nitrification process, which involves the conversion of ammonia (NH3) into nitrite (NO2-) and subsequently into nitrate (NO3-). Extensive human activities such as agriculture, thermal power generation, and automobile exhaust have led to an increase in the amounts of greenhouse gases and nitrogen pollution in soil and water. This comprehensive review highlights the importance of nitrogen-related processes for environmental sustainability and the role of nitrifying bacteria in combating nitrogen pollution. The focus of the current work is a detailed exploration of the diverse classes of nitrifying bacteria and their respective roles in environmental processes. Furthermore, the study explores practical applications of different classes of nitrifying bacteria, extending beyond the nitrification process. This review explored the potential of nitrifying bacteria in wastewater treatment, biodegradation of micropollutants, and the treatment of municipal solid waste leachate, showcasing the versatility of these bacteria in addressing broader environmental challenges.

Material extrusion-based 3D printing for the fabrication of bacteria into functional biomaterials: The case study of ammonia removal application

3D printing provides a new way of microbial immobilization technology and creates innovative designed bioactive structures containing microorganisms for remediation of environmental pollution. However, the bio-ink design remains a critical challenge due to the difficulty in creating a durable and bio-friendly material. Here, a novel dual-crosslinking PEGDA-Alginate-PVA-Nanoclay (PAPN) bio-ink containing one heterotrophic bacterium is reported for 3D printing functional biomaterial with the capabilities of ammonia removal. The results showed that PAPN 3D printed bio-scaffolds could effectively remove 96.2±1.3% ammonia within 12 hours, and the removal rate increased within repeated use owing to the growth of bacteria inside the bio-scaffolds. Preservation of the bio-scaffolds under room temperature without a culture medium for 168 hours still maintained the microbial activity for ammonia removal. It is demonstrated that visible-light-based 3D printing procedures could maintain high cell viability for the majority of bacteria, and the porous structures of 3D bio-scaffolds could allow the permeability of nutrients for the growth of bacteria. This work demonstrates the potential of the dual crosslinked PAPN 3D bio-scaffold for the production and application of immobilized functional bacteria in wastewater treatment. • 3D printed bio-scaffolds are proposed for ammonia removal in wastewater treatment. • PEGDA-Alginate-PVA-Nanoclay (PAPN) bio-ink shows high printability. • Dual crosslinking enhances mechanical properties of PAPN 3D bio-scaffold. • PAPN 3D bio-scaffolds maintain viability and stability via mild dual crosslinking. • 3D bio-scaffolds were effective and reusable for ammonia removal in water.

The roles of microalgae and bacteria in wastewater treatment

Nature-based wastewater treatment employing microalgae and bacteria has gained serious attention due to its combination with valuable biomass production. In wastewater, microalgae serves as the primary source of dissolved oxygen (DO) production for bacterial organic matter degradation. In addition, microalgae can effectively remove nutrients, pathogens as well as various heavy metals. Bacteria, on the other hand, has been widely applied in biological wastewater treatment for stabilization of organic matter, nitrification, denitrification, and under some specific conditions, enhanced biological phosphorus removal. When cultured together, microalgae and bacteria can cooperate effectively for wastewater treatment as well as form big flocs which can be harvested easily via sedimentation. However, some natural antagonistic interactions between them should be expected. Various environmental and operational factors showed significant influences on microalgae and bacteria in wastewater. They can impact system performance individually or in combination with others. Therefore, those factors should be carefully monitored for improving performance of the system.

Mutagenesis of high-efficiency heterotrophic nitrifying-aerobic denitrifying bacterium Rhodococcus sp. strain CPZ 24

Breeding high-efficiency heterotrophic nitrifying–aerobic denitrifying (SND) bacteria is important for the removal of biological nitrogen in wastewater treatment. In this study, a high-efficiency SND mutant strain, ΔRhodococcus sp. CPZ 24, was obtained by ultraviolet–diethyl sulfate compound mutagenesis. The maximum nitrification and denitrification rates were 3.77 and 1.37 mg·L−1·h−1, respectively 30.30 % and 17.10 % higher than those of wild bacteria. Biolog technology and network model analysis revealed that ΔCPZ 24 significantly improved the utilisation ability and metabolic activity of organic carbon sources. Furthermore, the expression levels of the nitrogen removal function genes nxrA, nosZ, amoA, and norB in strain ΔCPZ 24 increased significantly. In actual sewage, mutant bacteria ΔCPZ 24 have a 95.05 % ammonia–nitrogen degradation rate and a 96.67 % nitrate-nitrogen degradation rate. These results suggested that UV-DES compound mutation was a successful strategy to improve the nitrogen removal performance of SND bacteria in wastewater treatment.

Advances in the use of microalgal-bacterial consortia for wastewater treatment: Community structures, interactions, economic resource reclamation, and study techniques.

The rise in living standards has generated a demand for higher aquatic environmental quality. The microalgal community and the surrounding organic molecules, environmental factors, and microorganisms, such as bacteria, are together defined as the phycosphere. The bacteria in the phycosphere can form consortia with microalgae through various forms of interaction. The study of the species in these consortia and their relative proportions is of great significance in determining the species and strains of stable algae that can be used in sewage treatment. This article summarizes the following topics: the interactions between microalgae and bacteria that are required to establish consortia; how symbiosis between algae and bacteria is established; microalgal competition with bacteria through inhibition and anti-inhibition strategies; the influence of environmental factors on microalgal-bacterial aggregates, such as illumination conditions, pH, dissolved oxygen, temperature, and nutrient levels; the application of algal-bacterial aggregates to enhance biomass production and nutrient reuse; and techniques for studying the community structure and interactions of algal-bacterial consortia, such as microscopy, flow cytometry, and omics. PRACTITIONER POINTS: Community structures in microalgal-bacterial consortia in wastewater treatment. Interactions between algae and bacteria in wastewater treatment. Effects of ecological factors on the algal-bacterial community in wastewater treatment. Economically recycling resources from algal-bacterial consortia based on wastewater. Technologies for studying microalgal-bacterial consortia in wastewater treatment.

Metagenomics combined with DNA-based stable isotope probing provide comprehensive insights of active triclosan-degrading bacteria in wastewater treatment

The biotransformation of triclosan (TCS) during wastewater treatment occurred frequently, while little researches are known the identity of microorganisms involved in the biodegradation process. In this work, DNA-based stable isotope probing (DNA-SIP) was occupied to investigate the TCS assimilation microbes originated from a full-scale cyclic activated sludge system in Beijing. Results of TCS removal pathway showed that the TCS removal in nitrification process was mainly contributed by the metabolism of heterotrophic bacteria, accounting for about 18.54%. DNA-SIP assay indicated that Sphingobium dominated the degradation of TCS. Oligotyping analysis further indicated that oligotype GCTAAT and ATGTTA of Sphingobium played important roles in degrading TCS. Furthermore, the Kyoto Encyclopedia of Genes and Genomes functional abundance statistics based on PICRUSt2 showed that glutathione transferase was the most prevalent enzyme involved in TCS metabolism, and TCS might be removed through microbial carbon metabolism. Metagenomics made clear that Sphingobium might play irrelevant role on the propagation of antibiotics resistance genes (ARGs), even though, it could degrade TCS. Thauera and Dechloromonas were identified as the key hosts of most ARGs. This study revealed the potential metabolic pathway and microbial ecology of TCS biodegradation in nitrification process of wastewater treatment system.

Efficiency of Thermophilic Bacteria in Wastewater Treatment

The present work was carried out to assess the efficiency of thermophilic bacteria in wastewater treatment. A consortium of four thermophilic bacterial strains was used in this study. At 50 °C, the thermophilic consortium showed a very high efficiency in removing total organic carbon (TOC), which reached around 79% in 60 h. Removal of phosphorous was relatively low at 15.4%, while removal of nitrogen was about 83% in 60 h of incubation time. Dissolved oxygen was significantly decreased from 3.43 ppm down to 0.13 ppm in the same period. The consortium of mesophilic bacteria grown at 37 °C showed a substantially different performance from the thermophilic consortium incubated at 50 °C. For example, after 60 h of incubation at 37 °C, only 58.5% of TOC, 13.2% of phosphorous and 75.9% of nitrogen were removed, respectively. Dissolved oxygen was decreased from 3.43 ppm down to 0.28 ppm in the same period. Efficiency of removal rate by thermophilic conditions is higher than the mesophilic conditions. Properties such as fast growth of thermophiles (compared to mesophiles) may explain the exceptional ability of these thermophilic organisms in waste removal.

Microbial Fuel Cell for Electrical Power Generation from Waste Water

In the last decades, the microbial fuel cell (MFC) has increased great opportunity as an alternative energy source through electrochemical process for producing bio-energy. MFC has been involved in anode and cathode for electric energy generation from organic ingredients such as bacteria in waste water treatment. In this review, we discussed the different types of MFC (anode and cathode) materials with various integrations. In addition, it includes the gainful, biocompatible and exceedingly constant electrode materials with enhanced microbial fuel cell performance. Following this review, expansion in membrane materials such as hydrocarbon polymer, perfluorinated polymer, organic-organic hybrid polymer, ceramics, organic-inorganic hybrid composite, and biopolymer membranes are clarified in detail. In this paper, also highlighted the application of MFC technology and the methods used in the MFC in electricity production.

A Review on purple sulphur bacteria for waste Water treatment

A Review on purple sulphur bacteria for waste Water treatment

Nitrogen Removal by Co-Immobilized Anammox and Ammonia-Oxidizing Bacteria in Wastewater Treatment

In wastewater treatment, an alternative to the widely used aerobic nitrification with subsequent anoxic denitrification method is the combination of nitration and anammox (AMX) in one system. This study focuses on the co-immobilization of AMX and ammonia-oxidizing bacteria into a polyvinyl alcohol (PVA) hydrogel, and its effective use in nitrogen removal (NR). The NR process was performed in nine consecutive, repeated batches. By optimizing the conditions of the biotransformations, there was equal utilization of nitrogen in both sources, N–NH4+ and N–NO2−, at 100% NR during the sixth repetition. A significant increase in the immobilized co-culture activity was also detected per cycle. The maximum value of the NR rate was 3.46 mg N (L h)−1, and 100% NR efficiency was achieved with an initial concentration of 100.3 mg N L−1 for N–NH4+ and 60.1 mg N L−1 for N–NO2−, during the eighth batch biotransformation.

Metagenomics Study of the Microbes in Constructed Wetland System Treating Sewage

Constructed wetlands are ecofriendly, cost effective technology involved in treatment of wastewaters. The goal of this study is focused on characterization of microbial community existing in constructed wetland system planted with Cyperusalternifolius treating sewage contaminated with heavy metals. The characteristics of effluent met the standards of discharge for inland use and irrigation. Microbes in constructed wetland apparently play a pivotal role in the efficiency of system for removal of organics, nutrients, suspended solids and heavy metal. To expose the active players in the lime light, a representative soil sample from the reed bed was collected and characterized for microbial community analysis. Metagenomic studies of the bacterial and fungal flora were identified. Results revealed that the phylum Proteobacteria (38.27%) and Ascomycota (77.47%) dominated in the bacterial and fungal kingdom respectively. However, in the bacterial kingdom at species level major portion remain unclassified except Pseudomonasalcaligenes but in the fungal kingdom at species level only 3.1% remain unclassified. The role of bacteria in wastewater treatment is exemplified in previous reports but the role of fungi in wastewater system needs exploration. However, the findings reveal that the identified microbes might have definitely played a vital role in wastewater treatment. The database available for the identification of bacterial species remain undiscovered for a major portion and requires up gradation. Next generation sequence being a high end technology in microbial ecology decodes the entire community in environmental samples but lack of database limits the identification. Implementation of improvements in the paucity of data bases is essential.

Metagenomics Study of the Microbes in Constructed Wetland System Treating Sewage

Constructed wetlands are ecofriendly, cost effective technology involved in treatment of wastewaters. The goal of this study is focused on characterization of microbial community existing in constructed wetland system planted withCyperusalternifoliustreating sewage contaminated with heavy metals. The characteristics of effluent met the standards of discharge for inland use and irrigation. Microbes in constructed wetland apparently play a pivotal role in the efficiency of system for removal of organics, nutrients, suspended solids and heavy metal. To expose the active players in the lime light, a representative soil sample from the reed bed was collected and characterized for microbial community analysis. Metagenomic studies of the bacterial and fungal flora were identified. Results revealed that the phylum Proteobacteria (38.27%) and Ascomycota (77.47%) dominated in the bacterial and fungal kingdom respectively. However, in the bacterial kingdom at species level major portion remain unclassified exceptPseudomonasalcaligenesbut in the fungal kingdom at species level only 3.1% remain unclassified. The role of bacteria in wastewater treatment is exemplified in previous reports but the role of fungi in wastewater system needs exploration. However, the findings reveal that the identified microbes might have definitely played a vital role in wastewater treatment. The database available for the identification of bacterial species remain undiscovered for a major portion and requires up gradation. Next generation sequence being a high end technology in microbial ecology decodes the entire community in environmental samples but lack of database limits the identification. Implementation of improvements in the paucity of data bases is essential.

Identification of ceftazidime interaction with bacteria in wastewater treatment by Raman spectroscopic mapping.

Raman spectroscopy yields a fingerprint spectrum and is of great importance in medical and biological sciences as it is non-destructive, non-invasive, and available in the aqueous environment. In this study, Raman spectroscopy and Raman mapping were used to explore the dynamic biochemical processes in screened bacteria under ceftazidime stress. The Raman spectral difference between bacteria with and without antibiotic stress was analyzed by principal component analysis and characteristic peaks were obtained. The results showed that amino acids changed first and lipids were reduced when bacteria were exposed to ceftazidime stress. Furthermore, in Raman mapping, when bacteria were subjected to antibiotic stress, the peak at 1002 cm−1 (phenylalanine) increased, while the peak at 1172 cm−1 (lipids) weakened. This indicates that when bacteria were stimulated by antibiotics, the intracellular lipids decreased and the content of specific amino acids increased. The reduction of intracellular lipids may suggest a change of membrane permeability. The increase of specific amino acids suggests that bacteria resist external stimuli of antibiotics by regulating the activities of related enzymes. This study explored the processes of the action between bacteria and antibiotics by Raman spectroscopy, and provides a foundation for the further study of the dynamics of microbial biochemical processes in the future.

Discrepant effects of metal and metal oxide nanoparticles on anammox sludge properties: A comparison between Cu and CuO nanoparticles

Metal and metal oxide nanoparticles (NPs) show differences in antimicrobial activity due to different chemical and physical properties. Using copper as a representative example, this study compared the NP effects on anaerobic ammonium oxidation (anammox) bacteria in wastewater treatment. Long-term exposure to 5 mgCu L−1 CuNPs reduced the physiological activity and abundance of anammox bacteria, thereby causing deterioration of reactor performance. However, anammox granules exhibited stronger resistance and resilience to perturbation by 1–160 mgCu L−1 CuONPs, and no adverse effects on performance were observed. Moreover, the level of Cu(II) released from NPs in the influent exhibited good correlations with variations of the community structure and sludge properties. Therefore, the effects of Cu-based NPs on anammox sludge properties are dependent on their forms and levels, and their discrepant effects are partially attributed to their ability to release ionic copper.

Anammox granules show strong resistance to engineered silver nanoparticles during long-term exposure

The increasing use of engineered Ag nanoparticles (NPs) in consumer products raises great concerns about their environmental impacts, but their potential impact on anaerobic ammonium oxidation (anammox) bacteria in wastewater treatment remains unclear. In this study, the response of anammox consortia inhabiting in granules to long-term exposure of AgNPs was investigated. The gradually increased stress of AgNPs (1, 10, 50 mg L−1) showed no adverse effects on the nitrogen removal performance and on the relative abundance of Ca. Kuenenia inhabiting in granules. Notably, in response to the escalating burden of AgNPs, anammox consortia tended to secrete more protein but less polysaccharide, and meanwhile increase the relative abundances of Ag+ efflux protein SilA and regulatory protein SilR. Overall, these results suggested that the strong resistance of anammox granules to AgNPs might be mainly attributed to the defense role of extracellular polymeric substances and gene-based regulation of ion transport.

A novel flocculant prepared by lignin nanoparticles-gelatin complex from switchgrass for the capture of Staphylococcus aureus and Escherichia coli

Lignin nanoparticles (L-NPs) were firstly prepared from switchgrass lignin by using ultrasonic-assisted alkali method, after which L-NPs were assembled with gelatin to constitute L-NPs-gelatin complex as a novel flocculant. Both Gram-positive (Staphylococcus aureus, S.aureus) and Gram-negative (Escherichia coli, E.coli) strains were used to investigate the flocculation property of L-NPs and L-NPs-gelatin complex. It was found that L-NPs-gelatin complex exhibited relatively better flocculation capacity than L-NPs, in which the flocculation efficiency was greatly affected by pH and dosage. For both indicator strains, flocculation efficiency (>95%) was achieved within 30 min at pH 4.5, while the flocculation efficiency of 90% costed 60 min at pH 5. The L-NPs-gelatin complex was promising to be applied for flocculating bacteria in wastewater treatment, enrichment and detection of microorganism, etc.

The Zeolite-Anammox Treatment Process for Nitrogen Removal from Wastewater—A Review

Water quality in San Francisco Bay has been adversely affected by nitrogen loading from wastewater treatment plants (WWTPs) discharging around the periphery of the Bay. While there is documented use of zeolites and anammox bacteria in removing ammonia and possibly nitrate during wastewater treatment, there is little information available about the combined process. Though relatively large, zeolite beds have a finite ammonium adsorption potential and require periodic re-generation depending on the wastewater nitrogen loading. Use of anammox bacteria reactors for wastewater treatment have shown that ammonium (and to some degree, nitrate) can be successfully removed from the wastewater, but the reactors require careful attention to loading rates and internal redox conditions. Generally, their application has been limited to treatment of high-ammonia strength wastewater at relatively warm temperatures. Moreover, few studies are available describing commercial or full-scale application of these reactors. We briefly review the literature considering use of zeolites or anammox bacteria in wastewater treatment to set the stage for description of an integrated zeolite-anammox process used to remove both ammonium and nitrate without substrate regeneration from mainstream WWTP effluent or anaerobic digester filtrate at ambient temperatures.

Effects of ultraviolet disinfection on antibiotic-resistant Escherichia coli from wastewater: inactivation, antibiotic resistance profiles and antibiotic resistance genes.

To evaluate the effect of ultraviolet (UV) disinfection on antibiotic-resistant Escherichia coli. Antibiotic-resistant E.coli strains were isolated from a wastewater treatment plant and subjected to UV disinfection. The effect of UV disinfection on the antibiotic resistance profiles and the antibiotic resistance genes (ARGs) of antibiotic-resistant E.coli was evaluated by a combination of antibiotic susceptibility analysis and molecular methods. Results indicated that multiple-antibiotic-resistant (MAR) E.coli were more resistant at low UV doses and required a higher UV dose (20mJcm-2 ) to enter the tailing phase compared with those of antibiotic-sensitive E.coli (8mJcm-2 ). UV disinfection caused a selective change in the inhibition zone diameters of surviving antibiotic-resistant E.coli and a slight damage to ARGs. The inhibition zone diameters of the strains resistant to antibiotics were more difficult to alter than those susceptible to antibiotics because of the existence and persistence of corresponding ARGs. The resistance of MAR bacteria to UV disinfection at low UV doses and the changes in inhibition zone diameters could potentially contribute to the selection of antibiotic-resistant bacteria in wastewater treatment after UV disinfection. The risk of spread of antibiotic resistance still exists owing to the persistence of ARGs. Our study highlights the acquisition of other methods to control the spread of ARGs.

Copper Nanoparticle Induced Cytotoxicity to Nitrifying Bacteria in Wastewater Treatment: A Mechanistic Copper Speciation Study by X-ray Absorption Spectroscopy.

With the inclusion of engineered nanomaterials in industrial processes and consumer products, wastewater treatment plants (WWTPs) could serve as a major sink for these emerging contaminants. Previous research has demonstrated that nanomaterials are potentially toxic to microbial communities utilized in biological wastewater treatment (BWT). Copper-based nanoparticles (CuNPs) are of particular interest based on their increasing use in wood treatment, paints, household products, coatings, and byproducts of semiconductor manufacturing. A critical step in BWT is nutrient removal through nitrification. This study examined the potential toxicity of uncoated and polyvinylpyrrolidone (PVP)-coated CuO, and Cu2O nanoparticles, as well as Cu ions to microbial communities responsible for nitrification in BWT. Inhibition was inferred from changes to the specific oxygen uptake rate (sOUR) in the absence and presence of Cu ions and CuNPs. X-ray absorption fine structure spectroscopy, with linear combination fitting (LCF), was utilized to track changes to Cu speciation throughout exposure. Results indicate that the dissolution of Cu ions from CuNPs drive microbial inhibition. The presence of a PVP coating on CuNPs has little effect on inhibition. LCF analysis of the biomass combined with metal partitioning analysis supports the current hypothesis that Cu-induced cytotoxicity is primarily caused by reactive oxygen species formed from ionic Cu in solution via catalytic reaction intermediated by reduced Cu(I) species.

Application of deep-sea psychrotolerant bacteria in wastewater treatment by aerobic dynamic membrane bioreactors at low temperature

Wastewater treatment by biological processes was greatly hindered at low temperature. To improve the performance, screened deep-sea psychrotolerant strains were inoculated into an aerobic dynamic membrane bioreactor (ADMBR). The effect of bioaugmentation on reactor start-up, wastewater treatment performance, dynamic membrane formation, and membrane fouling under different temperature conditions was studied. Compared to the control reactor, the bioaugmented reactor showed a shorter start-up period, and better wastewater treatment performance at ≤15°C for a sudden decrease, and ≤7°C for a gradual decrease in temperature. Dehydrogenase activity in the bioaugmented reactor was enhanced at low temperature. Severe membrane fouling was not observed with bioaugmentation and the nonwoven fabric module we used was convenient to clean with tap water. Insoluble extracellular polymeric substances, especially insoluble protein were found to be responsible for membrane fouling. Fluorescence in situ hybridization (FISH) analysis displayed the dominance of two inoculated strains at the low temperature of 5°C. This study gave evidence that bioaugmentation with psychrotolerant strains was a feasible strategy to shorten the start-up time and to improve the wastewater treatment for ADMBR at low temperature.