The functional dominance and metabolic diversity of comammox Nitrospira in recirculating aquaculture systems.

As a newly discovered group of ammonia-oxidizing microorganisms, complete ammonia oxidizing (comammox) Nitrospira has been widely found in various oligotrophic ecosystems. However, their activity and ecological niche is still unclear in recirculating aquaculture systems (RAS). This study aimed to compare the abundance and activity of comammox Nitrospira, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and elucidate metabolic versatility of comammox Nitrospira in RAS.

The superiority of hydrophilic polyurethane in comammox-dominant ammonia oxidation during low-strength wastewater treatment.

Carriers have been extensively employed to enhance nitrification performance during low-strength wastewater treatment by retaining slow-growing ammonia oxidizing microorganisms (AOMs). Still, there is a dearth of systematic understanding of biofilm properties and microbial community structure formed on different carriers. In this study, hydrophilic polyurethane foam (PUF) carriers were prepared and compared with five widely used commercial carriers, namely Kaldness 3, Biochip, activated carbon, volcanic rock, and zeolite.

Effect of chlorine disinfectant influx on biological sewage treatment process under the COVID-19 pandemic: Performance, mechanisms and implications.

Since the onset of the COVID-19 Pandemic, large amounts of chlorine-containing disinfectants have been used to interrupt the spread of SARS-CoV-2 and residual chlorine eventually entered the hospital or municipal sewage treatment facilities. However, little is known about the effect of chlorine influx on the biological sewage treatment process. Here we investigated the effect of chlorine on the microbiome and the mechanism of microbial chlorine resistance in the activated sludge of the aerobic treatment process, using metagenomic and metatranscriptomic sequencing.

Advanced Treatment of Coking Wastewater by Polyaluminum Silicate Sulfate for Organic Compounds Removal.

Coking wastewater is a typical high-strength organic wastewater, for which it is difficult to meet discharging standards with a single biological treatment. In this study, effective advanced treatment of coking wastewater was achieved by coagulation with freshly prepared polyaluminum silicate sulfate (PASS). The performance advantage was determined through comparison with commercial coagulants including ferric chloride, polyferric sulfate, aluminum sulfate and polyaluminum chloride.

Ubiquitous occurrence and functional dominance of comammox Nitrospira in full-scale wastewater treatment plants.

The recent discovery of complete ammonia oxidation (comammox) bacteria has fundamentally upended the traditional two-step nitrification conception, but their functional importance in wastewater treatment plants (WWTPs) is still poorly understood. This study investigated distributions of comammox Nitrospira, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in activated sludge samples collected from 25 full-scale WWTPs. Using quantitative PCR (qPCR) and 16S rRNA gene amplicon sequencing, our results revealed that comammox Nitrospira ubiquitously occurred in all of 25 WWTPs and even outnumbered AOB and AOA with an average abundance of 1∼183 orders of magnitude higher in 19 WWTPs.

EasyAmplicon: An easy-to-use, open-source, reproducible, and community-based pipeline for amplicon data analysis in microbiome research.

It is difficult for beginners to learn and use amplicon analysis software because there are so many software tools to choose from, and all of them need multiple steps of operation. Herein, we provide a cross-platform, open-source, and community-supported analysis pipeline EasyAmplicon. EasyAmplicon has most of the modules needed for an amplicon analysis, including data quality control, merging of paired-end reads, dereplication, clustering or denoising, chimera detection, generation of feature tables, taxonomic diversity analysis, compositional analysis, biomarker discovery, and publication-quality visualization.

Predominance of comammox bacteria among ammonia oxidizers under low dissolved oxygen condition.

Although low-oxygen nitrification can significantly cut down the aeration demand in wastewater treatment plants, little is known about the community dynamics of relevant microorganisms under different oxygen concentrations. Here, by conducting a series of bioreactors with oxygen concentrations of 0%, 2%, 5%, 10%, 20%, 40%, and 70%, we provided a comprehensive investigation on the behaviors and performances of comammox bacteria (CMX), ammonia-oxidizing bacteria (AOB) and archaea (AOA) during the nitrification process. Quantitative PCR analysis demonstrated that CMX was the dominant ammonia-oxidizer under low oxygen condition (10%) after the four-month operation with the abundance increased by 8.

Three Gorges Dam: friend or foe of riverine greenhouse gases?

Dams are often regarded as greenhouse gas (GHG) emitters. However, our study indicated that the world's largest dam, the Three Gorges Dam (TGD), has caused significant drops in annual average emissions of CO, CH and NO over 4300 km along the Yangtze River, accompanied by remarkable reductions in the annual export of CO (79%), CH (50%) and NO (9%) to the sea. Since the commencement of its operation in 2003, the TGD has altered the carbonate equilibrium in the reservoir area, enhanced methanogenesis in the upstream, and restrained methanogenesis and denitrification via modifying anoxic habitats through long-distance scouring in the downstream.

Coupling strategies for ecotoxicological assessment of neonicotinoid insecticides based on their selective lethal effects: Design, screening, and regulation.

The recently recognized adverse environmental and toxic effects of neonicotinoid insecticides (NNIs) on non-target organisms are alarming. A comprehensive design, screening, and regulatory system was developed to generate NNI derivatives and mutant receptors with selective-ecotoxicological effects to overcome such adverse effects. For ligand design, taking ACE-09 derivative as an example, the toxicity on non-target animals (aboveground: bees; underground: earthworms), plant absorption, and soil absorption decreased by 4.

Comammox bacteria predominate among ammonia-oxidizing microorganisms in municipal but not in refinery wastewater treatment plants.

Comammox bacteria have proved to be one dominant and significant ammonia-oxidizing microorganisms (AOMs) in municipal wastewater treatment plants (WWTPs), however, it still remains unknown about their abundance and diversity in industrial WWTPs. In this study, activated sludge samples from 8 municipal WWTPs and 6 industrial WWTPs treating refinery wastewater were taken and analyzed using qPCR and amoA gene sequencing. Intriguingly, quantitative real-time PCR (qPCR) results suggested that comammox bacteria had a higher numerical abundance compared with ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in municipal WWTPs but did not in refinery WWTPs.

Effect of Sonochemical Treatment on Thermal Stability, Elemental Mercury (Hg) Removal, and Regenerable Performance of Magnetic Tea Biochar.

Elemental mercury (Hg) removal from a hot gas is still challenging since high temperature influences the Hg removal and regenerable performance of the sorbent. In this work, a facile yet innovative sonochemical method was developed to synthesize a thermally stable magnetic tea biochar to capture the Hg from syngas. A sonochemically synthesized magnetic sorbent (TUF) exhibited a more prodigious surface area with developed pore structures, ultra-paramagnetic properties, and high dispersion of FeO/γ-FeO particles than a simply synthesized magnetic sorbent (TF).

Mitigating NO and NO emissions from a pilot-scale oxidation ditch using bioaugmentation of immobilized aerobic denitrifying bacteria.

Nitrous oxide (NO) emission from wastewater treatment plants (WWTPs) requires urgent mitigation because of its significant contribution to the greenhouse effect. In this study, bioaugmentation was applied in a pilot-scale oxidation ditch with the aerobic denitrifying bacteria strain PCN-1 immobilized on polyurethane biocarriers, which demonstrated effective NO mitigation. Microbial community analysis suggested that the bioaugmentation facilitated a symbiotic relationship of the bacterial populations between the activated sludge and the biocarriers.

Uranium bioremediation with U(VI)-reducing bacteria.

Uranium (U) pollution is an environmental hazard caused by the development of the nuclear industry. Microbial reduction of hexavalent uranium (U(VI)) to tetravalent uranium (U(IV)) reduces U solubility and mobility and has been proposed as an effective method to remediate uranium contamination. In this review, U(VI) remediation with respect to U(VI)-reducing bacteria, mechanisms, influencing factors, products, and reoxidation are systematically summarized.

Determinants and implications of environmental practices for waste management and the minimization in the construction industry: a case study of Pakistan.

The construction projects and activities generate waste materials, which impose negative impacts on the environment and contribute towards environmental degradation. In this regard, the implementation of environmental practices (EPs) can play a vital role in reducing the environmental risks associated with waste materials from construction projects. Based on this hypothesis, the present survey study was conducted to assess the effectiveness of different EPs in reducing environmental risks associated with waste materials from construction firms (n = 159) operating in Pakistan.

Active ammonia-oxidizing bacteria and archaea in wastewater treatment systems.

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are two microbial groups mediating nitrification, yet little is presently known about their abundances and community structures at the transcriptional level in wastewater treatment systems (WWTSs). This is a significant issue, as the numerical abundance of AOA or AOB at the gene level may not necessarily represent their functional role in ammonia oxidation. Using amoA genes as molecular markers, this study investigated the transcriptional abundance and community structure of active AOA and AOB in 14 WWTSs.

Preparation of water-soluble chitosan/poly-gama-glutamic acid-tanshinone IIA encapsulation composite and its in vitro/in vivo drug release properties.

Some diseases could be treated by Tanshinone IIA (TA), which is an isolated component from the Chinese medicinal herb Tanshen (Salvia miltiorrhiza). However, the poor water solubility and low oral bioavailability of TA limited its clinical application. In this paper, TA was encapsulated by water - soluble chitosan/poly - γ - glutamic acid (WCS-γ-PGA) to improve its dissolution and oral bioavailability.

Nitrous oxide (NO) emissions from a pilot-scale oxidation ditch under different COD/N ratios, aeration rates and two shock-load conditions.

Nitrous oxide (NO) generated from wastewater treatment plants (WWTPs) has drawn attention due to its high emission load and significant greenhouse effect. In the present study, NO emissions from a pilot-scale Carrousel oxidation ditch under various chemical oxygen demand (COD) to nitrogen ratio (COD/N) and aeration rates were systematically investigated. The highest NO emission factor was 0.

Combined remediation of polychlorinated naphthalene-contaminated soil under multiple scenarios: An integrated method of genetic engineering and environmental remediation technology.

This study explored the types of polychlorinated naphthalene (PCN)-contaminated soil and determined the practicable scheme of combined remediation using an integrated method of genetic engineering and environmental remediation technology. A multi-scenario comprehensive evaluation system of a plant-microbial combined bioremediation of PCN-contaminated soil was established using the intelligent integration of analytic hierarchy process and formula evaluation methods based on the current situation of PCN contamination in China, which showed the bioremediation of PCN-contaminated soil by the plant-microbial system could be divided into four scenarios. QSAR models were constructed to quantify the remediation mechanism that electronic parameter ∆E was the key factor changing the efficiency of combined bioremediation.

Comammox Nitrospira within the Yangtze River continuum: community, biogeography, and ecological drivers.

The recent discovery of comammox Nitrospira as complete nitrifiers has fundamentally renewed perceptions of nitrogen cycling in natural and engineered systems, yet little is known about the environmental controls on these newly recognized bacteria. Based on improved phylogenetic resolution through successful assembly of ten novel genomes (71-96% completeness), we provided the first biogeographic patterns for planktonic and benthic comammox Nitrospira in the Yangtze River over a 6030 km continuum. Our study revealed the widespread distributions and relative abundance of comammox Nitrospira in this large freshwater system, constituting 30 and 46% of ammonia-oxidizing prokaryotes (AOPs) and displaying 30.

Efficient adsorption of europium (III) and uranium (VI) by titanate nanorings: Insights into radioactive metal species.

Radioactive wastewater containing high concentration of radionuclides poses severe threats to ecosystem and human health, so efficient removal of these toxic heavy metals is urgently needed. Titanate nanomaterials have been demonstrated good adsorbents for heavy metals due to ion exchange property. In this study, titanate nanorings (TNRs) were synthesized using the facile hydrothermal-cooling method.