RESUMO A epidemiologia baseada em esgotos é uma importante ferramenta de saúde pública com grande aplicabilidade no enfrentamento à pandemia de COVID-19, visto que indivíduos infectados são capazes de excretar partículas de SARS-CoV-2. Diante desse contexto, este estudo objetivou correlacionar o número de casos de COVID-19 com variáveis físicas e químicas e presença do vírus em amostras de esgoto bruto provenientes de uma estação de tratamento de esgoto (ETE) do município de Lavras (MG) coletadas entre as 19ª e 25ª semanas epidemiológicas. As amostras foram concentradas pelo método de adsorção em membrana eletronegativa, e o RNA de SARS-CoV-2 foi extraído, detectado e quantificado por reação da transcriptase reversa seguida pela reação em cadeia da polimerase (RT-qPCR) utilizando-se oligonucleotídeos e sondas para o gene N. Ademais, as variáveis pH, sólidos suspensos totais e demanda química de oxigênio foram avaliadas. Os casos de COVID-19 foram obtidos de boletins epidemiológicos disponibilizados pela prefeitura. Na 24ª semana epidemiológica, observou-se redução na concentração viral (cópias L-1) concomitantemente às medidas de enfrentamento à pandemia iniciadas pelo município. Correlação positiva forte e significativa (p < 0,05) entre carga viral e número de casos confirmados foi obtida por meio do teste de Spearman, entretanto não houve correlação entre a presença do vírus e as características físicas e químicas do esgoto. Sugere-se, portanto, que novas pesquisas sejam realizadas com a finalidade de rastrear a concentração de SARS-CoV-2 em águas residuárias, corroborando, desse modo, com o enfrentamento à pandemia e a obtenção de sistemas de vigilância epidemiológica por meio do monitoramento de esgotos.

ABSTRACT Wastewater-based epidemiology is an important public health tool with great applicability when facing the COVID-19 pandemic, since infected individuals are able to excrete SARS-CoV-2 particles. In this context, this study aimed to correlate the number of cases of COVID-19 with physical and chemical variables and the presence of the virus in raw sewage samples from a sewage treatment plant (STP) in the municipality of Lavras, Minas Gerais, Brazil, collected between the 19th and 25th epidemiological weeks. The samples were concentrated by electronegative membrane adsorption method and SARS-CoV-2 RNA was extracted, detected, and quantified by RT-qPCR using oligonucleotides and probes for the N gene. Moreover, the variables pH, total suspended solids, and chemical oxygen demand were evaluated. COVID-19 cases were obtained from epidemiological bulletins made available by the municipal government. From the 24th epidemiological week on, a reduction in viral concentration (copies L-1) was observed concomitantly with the pandemic response countermeasures initiated by the municipality. A strong and significant positive correlation (p<0.05) between viral load and number of confirmed cases was obtained through Spearman’s test. However, there was no correlation between the presence of the virus and the physical and chemical characteristics of the sewage. Therefore, it is suggested that further research be carried out in order to track SARS-CoV-2 concentrations in wastewater, thus corroborating with the fight against the pandemic and the achievement of epidemiological surveillance systems based on sewage monitoring.

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.

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.