Global insight into the occurrence, treatment technologies and ecological risk of emerging contaminants in sanitary sewers: Effects of the SARS-CoV-2 coronavirus pandemic.

The SARS-CoV-2 pandemic caused changes in the consumption of prescribed/non-prescribed drugs and the population's habits, influencing the detection and concentration of emerging contaminants (ECs) in sanitary sewage and harming environmental and health risks. Therefore, the present work sought to discuss current literature data on the effects of the "COVID-19 pandemic factor" on the quality of raw sewage produced over a five-year period (2018-2019: pre-pandemic; 2020-2022: during the pandemic) and biological, physical, chemical and hybrid treatment technologies, influencing factors in the removal of ECs and potential ecological risks (RQs). Seven hundred thirty-one publications correlating sewage and COVID-19 were identified: 184 pre-pandemic and 547 during the pandemic. Eight classes and 37 ECs were detected in sewage between 2018 and 2022, with the "COVID-19 pandemic factor" promoting an increase in estrogens (+31,775 %), antibiotics (+19,544 %), antiepileptics and antipsychotics (+722 %), pesticides (+200 %), analgesics, anti-inflammatories and anticoagulants (+173 %), and stimulant medications (+157 %) in sanitary sewage. Among the treatment systems, aerated reactors integrated into biomembranes removed >90 % of cephalexin, clarithromycin, ibuprofen, estrone, and 17ß-estradiol. The absorption, adsorption, and biodegradation mechanisms of planted wetland systems contributed to better cost-benefit in reducing the polluting load of sewage ECs in the COVID-19 pandemic, individually or integrated into the WWTP. The COVID-19 pandemic factor increased the potential ecological risks (RQs) for aquatic organisms by 40 %, with emphasis on clarithromycin and sulfamethoxazole, which changed from negligible risk and low risk to (very) high risk and caffeine with RQ > 2500. Therefore, it is possible to suggest that the COVID-19 pandemic intensified physiological, metabolic, and physical changes to different organisms in aquatic biota by ECs during 2020 and 2022.

COVID-19 cases, vaccination, and SARS-CoV-2 in wastewater: insights from a Brazilian municipality.

Vaccines combatting COVID-19 demonstrate the ability to protect against disease and hospitalization, and reduce the likelihood of death caused by SARS-CoV-2. In addition, monitoring viral loads in sewage emerges as another crucial strategy in the epidemiological context, enabling early and collective detection of outbreaks. The study aimed to monitor the viral concentration of SARS-CoV-2 in untreated sewage in a Brazilian municipality. Also, it attempted to correlate these measurements with the number of clinical cases and deaths resulting from COVID-19 between July 2021 and July 2022. SARS-CoV-2 viral RNA was quantified by RT-qPCR. Pearson's correlation was performed to analyze the variables' relationship using the number of cases, deaths, vaccinated individuals, and viral concentration of SARS-CoV-2. The results revealed a significant negative correlation (p < 0.05) between the number of vaccinated individuals and the viral concentration of SARS-CoV-2, suggesting that after vaccination, the RNA viral load concentration was reduced in the sample population by the circulating concentration of wastewater. Consequently, wastewater monitoring, in addition to functioning as an early warning system for the circulation of SARS-CoV-2 and other pathogens, can offer a novel perspective that enhances decision-making, strengthens vaccination campaigns, and contributes to authorities establishing systematic networks for monitoring SARS-CoV-2.

Organic stabilization and methane production under different organic loading rates in UASB treating swine wastewater.

This study proposes the was to evaluate the stability and methane production with organic load differents in an upflow anaerobic sludge blanket reactor (UASB) treating swine wastewater by methods of multivariate analysis. Four organic loads were used with average hydraulic holding times of one day. The methods of data analysis of linear regression, Pearson correlation, principal component analysis and hierarchical clustering analysis were used for understanding stability and methane production in the reactor. The highest concentrations of bicarbonate alkalinity of 683 mg L-1 CaCO3 and total volatile acids of 1418 mg L-1 HAc with maximum organic loading applied were obtained. The optimal stability conditions occurred at an intermediate and partial alkalinity ratio between 0.24 and 0.25 observed in initial phases with a chemical oxygen demand (COD) removal of 47-57%. Maximum methane production was 9.0 L CH4 d-1 observed with linear regression positive and occurred at the highest applied organic load, corresponding to the highest COD removal efficiency and increased microbial biomass. Positive and negative correlation between functional stability in anaerobic digestion showed regular activity between acids, alkalinity and organic matter removal. This fact was also proven by the analysis of principal components that showed three components responsible for explaining 83.2% of the data variability, and the alkalinity, organic matter influent and organic acids had the greatest effects on the stability of the UASB reactor. Hierarchical clusters detected the formation of five groupings with a similarity of 50.1%, indicating that temperature and pH were variables with unitary influences on data dimensionality.

Diversity and dynamics of bacterial communities in the drinking water distribution network of a mid-sized city in Brazil.

This study assessed the bacterial community composition of a drinking water system (DWS) serving a mid-sized city (120,000 inhabitants) in Brazil. Water samples, including raw and treated water, were collected at seven points throughout the DWS. DNA was extracted and analysed using high-throughput sequencing (Ion Torrent). Free chlorine and turbidity were measured in situ. Results showed that the highest relative abundance of 16S rRNA genes was from phyla Proteobacteria, followed by Bacteroidetes and Actinobacteria. The next most abundant phylum was Cyanobacteria, represented by Arthronema, Calothrix, and Synechococcus. An interesting observation was that the DNA-based analysis suggested a bacterial community change in the distribution network, with treated reservoir water being very different from the network samples. This suggests active microbiology within the distribution network and a tendency for bacterial diversity to decrease after chlorine disinfection but increase after pipeline distribution. In raw water, a predominance of Proteobacteria was observed with reduced Cyanobacteria, showing a negative correlation. In treated water, Proteobacteria were negatively correlated with Bacteroidetes. Finally, 16S rRNA genes from Firmicutes (especially Staphylococcus) had a high abundance in the chlorinated water, which may indicate the phylum's resistance to chlorine residuals. Opportunistic pathogens, e.g., Mycobacteria, Legionella, and Staphylococcus, were also observed.

Microbial dynamics and methanogenic potential of co-digestion of sugarcane vinasse and dairy secondary effluent in an upflow anaerobic sludge blanket reactor.

Co-digestion is a strategy that may prevent microbial inhibition during the anaerobic treatment of sugarcane vinasse, a substrate with highly biodegradable organic load, acidity, and toxic compound levels (e.g., sulfates, phenols). In this context, this study evaluated the microbial dynamics and methanogenic potential throughout the co-digestion of sugarcane vinasse and secondary effluent from the dairy industry in a mesophilic lab-scale upflow anaerobic sludge blanket (UASB) reactor. Periodic next-generation sequencing (NGS) analyses revealed an increase in the relative abundance of the phylum Euryarchaeota (+8.6 % after inoculation), predominating hydrogenotrophic methanogens (Methanobacterium and Methanobrevibacter) at the end of the operation. Moreover, the average methane yield was 221 mLCH4 gCODrem-1, with 69 % of organic matter removal. These results evidenced a progressive acclimation of the anaerobic microbial community to the substrate and a stable operation. Therefore, the proposed experiment demonstrates energy advantages for the agro-industrial sector by implementing a similar but full-scale treatment plant.

Nitratation in pilot-scale bioreactors fed with effluent from a submerged biological aerated filter used in the treatment of dog wastewater.

Nitrification is a biochemical process that allows oxidation of ammonium ion to nitrite, and nitrite to nitrate in a system. Aerobic processes, such as use of submerged biological aerated filter (SBAF), enable nitrification. However, some variables that are entirely unavailable or not available at the required concentration range may hamper the process. In this study, nitratation under high dissolved oxygen (DO) concentrations was evaluated in laboratory-scale bioreactors containing 10% inoculum (0.5 kg kg-1) fed with affluent from a SBAF that receive the sewage generated from washing the bays of a dog kennel. The following variables were monitored over time: ammoniacal nitrogen (12.44-29.62 mg L-1), nitrite (0.28-0.54 mg L-1), nitrate (1.75-3.55 mg L-1), pH (8.11 ± 0.62), temperature (21.61 ± 1.24°C) and DO (9.69 ± 0.36 mg L-1). Quantification of nitrifying bacteria by the multiple tube technique showed the value of 1.4 × 1012 MPN mL-1for ammonia-oxidizing bacteria (AOB) and 9.2 × 1014 MPN mL-1 for nitrite-oxidizing bacteria. These values were higher than those found in a synthetic medium, which can be explained by the greater availability of ammonium and nitrite in the effluent. By the extraction of genomic DNA, and PCR, with specific primers, the presence of the AmoA (Ammonia monooxygenase) gene for AOB and of the Nitrobacter was detected in the bioreactor samples. By PCR-DGGE, the sequenced bands showed high similarity with denitrifying bacteria, such as Pseudomonas, Limnobacter, Thauera, Rhodococcus, and Thiobacillus. Thus, the saturation of dissolved oxygen in the system resulted in improvement in the nitratation step and allowed detection of bacterial genera involved in the process.

Evaluation of nitrogen removal and the microbial community in a submerged aerated biological filter (SABF), secondary decanters (SD), and horizontal subsurface flow constructed wetlands (HSSF-CW) for the treatment of kennel effluent.

To ensure microbial activity and a reaction equilibrium with efficiency and energy saving, it is important to know the factors that influence microbiological nitrogen removal in wastewater. Thus, it was investigated the microorganisms and their products involved in the treatment of kennel effluents operated with different aeration times, phase 1 (7 h of continuous daily aeration), phase 2 (5 h of continuous daily aeration), and phase 3 (intermittent aeration every 2 h), monitoring chemical and physical parameters weekly, monthly microbiological, and qualitative and quantitative microbiological analyzes at the end of each applied aeration phase. The results showed a higher mean growth of nitrifying bacteria (NB) (106) and denitrifying bacteria (DB) (1022) in phase with intermittent aeration, in which better total nitrogen (TN) removal performance, with 33%, was achieved, against 21% in phase 1 and 17% in phase 2, due to the longer aeration time and lower carbon/nitrogen ratio (15.7), compared with the other phases. The presence of ammonia-oxidizing bacteria (AOB), the genus Nitrobacter nitrite-oxidizing bacteria (NOB), and DB were detected by PCR with specific primers at all phases. The analysis performed by 16S-rRNA DGGE revealed the genres Thauera at all phases; Betaproteobacteria and Acidovorax in phase 3; Azoarcus in phases 2 and 3; Clostridium, Bacillus, Lactobacillus, Turicibacter, Rhodopseudomonas, and Saccharibacteria in phase 1, which are related to the nitrogen removal, most of them by denitrifying. It is concluded that, with the characterization of the microbial community and the analysis of nitrogen compounds, it was determined, consistently, that the studied treatment system has microbiological capacity to remove TN, with the phase 3 aeration strategy, by simultaneous nitrification and denitrification (SND). Due to the high density of DB, most of the nitrification occurred by heterotrophic nitrification-aerobic. And denitrification occurred by heterotrophic and autotrophic forms, since the higher rate of oxygen application did not harm the DB. Therefore, the aeration and carbon conditions in phase 3 favored the activity of the microorganisms involved in these different routes. It is considered that, in order to increase autotrophic nitrification-aerobic, it is necessary to exhaust the volume of sludge in the secondary settlers (SD), further reducing the carbon/nitrogen ratio, through more frequent cleaning, whose periodicity should be the object of further studies. Graphical abstract.

Quantification, removal and potential ecological risk of emerging contaminants in different organic loads of swine wastewater treated by integrated biological reactors.

This study aims to evaluate the dynamics and their ecological risks for aquatic species of lipid regulator, nervous stimulant, anti-inflammatory and endocrine disrupters in an upflow anaerobic sludge blanket (UASB), submerged aerated biological filters (SABF) and horizontal subsurface flow constructed wetland (HSSF-CW) reactors that treat swine wastewater. Four organic loads of swine wastewater (SW) were used according to changing the chemical oxygen demand. 13 contaminants were quantified, standing out the endocrine disruptors, lipid regulator and anti-inflammatory. In phase III, 8318.4 ng L-1 of 4-ocylphenol was found at the influent of the UASB reactor and removal from 1877.1 to 13.7 ng L-1 in the bisphenol A system. With the maximum organic load, there was a reduction among all the treatment units, with concentrations between 1877.1 and 13.7 ng L-1 of bisphenol A and had naproxen removal of 94.5% and 2,7 ng L-1 after treating phases II and III. It was found that 24.6% of the contaminants presented a high ecological risk, with maximum values of 27.4 (4-nonylphenol, phase II), 24.6 and 5.9 (17ß-estradiol, phase IV and I, respectively), 13.4 (4-ocylphenol, phase III) and 4.4 (estrone, phase IV) in the influent system. The reduction of ecological risk potentials was optimized by SABF and HSSF-CW. The effect oxygen availability and microbiological activities optimized the reduction of ecological risks on zebrafish (Danio rerio) and cnidarian (Hydra attenuata) species, moreover, the reduction of mass flows and ecological risks of the emerging contaminants are associated with the use of biological reactors in series and organic stabilizations.

Principal component analysis as a criterion for monitoring variable organic load of swine wastewater in integrated biological reactors UASB, SABF and HSSF-CW.

The multivariate analysis to optimize the parameters of wastewater is essential to reduce costs. The aim of this study was to evaluate the use of multivariate and conventional analysis in biological system composed by upflow anaerobic sludge blanket (UASB), submerged aerated biological filters (SABF) and horizontal subsurface flow constructed wetland (HSSF-CW) reactors in the organic stabilization of swine wastewater (SW). Four loads were used in the system with alteration by COD concentration of untreated SW, and the data were evaluated by principal components (PCA). The average efficiency of COD and BOD removal increased from 45% in phase I to 67% in phase IV in the UASB, SABF and HSSF-CW reactors. The principal component analysis promoted the reduction of 13 original variables to 5, 8 and 5 principal components in the UASB, SABF and HSSF-CW reactors, respectively, optimizing the dynamics of interpretation of the data that influenced the most the stability of the wastewater system across the four phases. There was a strong negative effect of oxygen concentrations in the SABF reactor in relation to organic variables, optimizing the biological mechanisms of the HSSF-CW and, therefore, enabling better decision making and cost reduction with analysis at treatment plants.

Use of Coffee Capsules as Support Material in Upflow Anaerobic Fixed Bed Reactors

Abstract The aim of this work is to evaluate the performance of upflow anaerobic fixed bed reactors filled with espresso coffee capsules to treat sanitary sewage. Three reactors (R1, R2 and R3) were constructed in blue PVC pipes measuring 30 cm height and 150 mm diameter and filled with coffee capsules made of aluminum and plastic. The sewage from the pre-treatment phase of the wastewater treatment plant of the Federal University of Lavras fed the system. Temperature, pH, alkalinity and volatile acids concentration, COD, TS, TVS and TSS of the influent and effluent were analyzed to evaluate the reactors performances. Statistics tests were run in the software Statistica 10. Changes occurred in the organic loading rates caused two different operating phases, one at an OLR of 2.1 kg COD m-3d-1 and another at 4.0 kg COD m-3d-1. The average temperature during the monitoring period was 18°C. In spite of the operating conditions variations, the reactors showed satisfactory performances, presenting COD efficiency removals up to 80% in both phases. The capsules characteristics were similar to other materials used as support. Hence, it is possible to utilize coffee capsules as support material in anaerobic reactors, providing satisfactory pollutants removal efficiencies.

Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs.

Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.

Enriquecimento de microrganismos metanotróficos a partir de lodo de reator UASB tratando esgotos domésticos / Enrichment of methanotrophic microorganisms from sludge of UASB reactor treating domestic sewage

RESUMO Nesse estudo, microrganismos metanotróficos foram enriquecidos a partir de lodo proveniente de um reator UASB tratando esgotos domésticos em reator em batelada sequencial (RBS) com meio autotrófico contendo nitrito e nitrato. As eficiências médias de remoção de nitrito e nitrato foram de 68% e 53%, respectivamente, provavelmente devido à atividade heterotrófica desnitrificante. A detecção de arquéias dos grupos ANME-I e ANME-II foram realizadas por PCR durante todo período de cultivo. A estrutura da comunidade microbiana presente no inóculo e enriquecida no RBS após 100 dias de operação foi estudada por pirosequenciamento. Os resultados das análises demonstraram que a comunidade enriquecida no reator foi diferente à inoculada. Os filos dominantes no inóculo foram Synergistestes , Firmicutes e Euryarchaeota , ao passo que na biomassa enriquecida Planctomycetes, Verrucomicrobia, Chloroflexi e Proteobacteria predominaram. As condições de cultivo do RBS reduziram a abundância de Methanobacterium (8% para 1%) e selecionaram bactérias metanotróficas como Methylocaldum , Methylocistis e Methylosinus . As sequências de Methylocaldum sp. apresentaram abundância relativa de 2.5%. A presença e elevada predominância do filo Verrucomicrobia na biomassa enriquecida do RBS sugere que outras espécies de metanotróficas, ainda pouco conhecidas, relacionadas a este filo podem estar presentes no reator. O potencial de oxidação anaeróbia do metano foi determinado para ambas amostras e revelaram que a atividade metanotrófica da biomassa foi aproximadamente três vezes maior que a do inóculo. Em suma, estes resultados sugerem que o inóculo usado e as condições de cultivo aplicadas foram adequados para o enriquecimento de metanotróficas.

ABSTRACT In this study, methanotrophic microorganisms were enriched from sludge derived from a UASB reactor treating domestic sewage. The enrichment was performed in a sequencing batch reactor (RBS) with an autotrophic medium containing nitrite and nitrate. The nitrite and nitrate removal efficiencies were 68% and 53%, respectively, probably due to heterotrophic denitrification. Archaeal cells of the ANME-I and ANME-II groups were detected by PCR throughout the whole cultivation period. The microbial community composition of the biomass present in the inoculum and enriched in RBS after 100 days of operation was investigated and compared with the help of data obtained from pyrosequencing analyses. Pyrosequencing analysis demonstrated that the community enriched in the reactor had differing composition from the inoculum. The dominant phyla detected in the inoculum were Synergistestes , Firmicutes and Euryarchaeota while in the enriched biomass Planctomycetes, Verrucomicrobia, Chloroflexi and Proteobacteria predominated. The cultivation conditions applied decreased the abundance of Methanobacterium (from 8 to 1%) and selected for methanotrophic bacteria such as Methylocaldum , Methylocistis and Methylosinus . Sequences of Methylocaldum sp. accounted for 2.5% of the total reads. The presence and high predominance of Verrucomicrobia in the enriched biomass suggest that other unknown methanotrophic species related to this phylum might also have occurred in the reactor. The potential for anaerobic oxidation of methane was determined for both samples and revealed that the methanotrophic activity of the enriched biomass was almost three times greater than in the inoculum. Taken together these results indicated that the inoculum used and the cultivation conditions applied were adequate for the methanotrophic enrichment.

Enrichment and activity of methanotrophic microorganisms from municipal wastewater sludge.

In this study, methanotrophic microorganisms were enriched from a municipal wastewater sludge taken from an Upflow Anaerobic Sludge Blanket reactor. The enrichment was performed in a sequencing batch reactor (SBR) with an autotrophic medium containing nitrite and nitrate. The microbial community composition of the inoculum and of the enrichment culture after 100 days of SBR operation was investigated and compared with the help of data obtained from 454 pyrosequencing analyses. The nitrite and nitrate removal efficiencies were 68% and 53%, respectively, probably due to heterotrophic denitrification. Archaeal cells of the anaerobic methanotrophic Archaic (ANME)-I and ANME-II groups were detected by polymerase chain reaction throughout the whole cultivation period. Pyrosequencing analysis showed that community composition was different among the two samples analysed. The dominant phyla found in the inoculum were Synergistestes, Firmicutes and Euryarchaeota, while Planctomycetes, Verrucomicrobia, Chloroflexi and Proteobacteria prevailed in the enriched biomass. The cultivation conditions decreased Methanobacterium abundance from 8% to 1%, and enriched for methanotrophic bacteria such as Methylocaldum, Methylocistis and Methylosinus. Sequences of Methylocaldum sp. accounted for 2.5% of the total reads. The presence and high predominance of Verrucomicrobia in the enriched biomass suggested that other unknown methanotrophic species related to that phylum might also have occurred in the reactor. Anaerobic methane oxidation activity was measured for both samples, and showed that the activity of the enrichment culture was nearly three times higher than the activity of the inoculum. Taken together, these results showed that the inoculum type and cultivation conditions were properly suited for methanotrophic enrichment.