COVID-19 is currently the most critical disease in the world. Thus, several tools have been used in the last two years to contain the spread of SARS-CoV-2. In this perspective, Wastewater-Based Epidemiology (WBE) provides valuable data by including symptomatic, pre-symptomatic, and asymptomatic individuals and anticipating clinical cases. For 37 weeks, the SARS-CoV-2 viral load was monitored in sanitary sewage samples from Goiânia-Brazil. Through pre-concentration, extraction, and purification of viral RNA, followed by RT-qPCR, it was detected in 83.78% (31/37) of the weeks the presence of fragments of the genetic material SARS-CoV-2 with viral loads ranging from 105 to 108 genome copies L-1. The viral load in the wastewater samples was related to the clinical data of the municipality, demonstrating its ability to promote an Early Warning System (EWS). In early 2022, it was possible to predict the increase in clinical cases 3 weeks in advance and issue an alert note to the health authorities. Prevalence estimates ranged from 0.003 to 0.5% and showed good agreement with observed values. Thus, monitoring effluents become another essential tool that can help combat the pandemic’s advance, especially in countries with scarce resources.

RESUMO A vigilância da qualidade dos esgotos sanitários pode representar uma ferramenta complementar para monitoramento de doenças infecciosas e prevenção de surtos epidêmicos, especialmente quando a capacidade para testes clínicos é limitada. Dessa maneira, o presente estudo descreve o detalhamento técnico de um método de baixo custo para a concentração e extração de ácidos nucleicos de amostras de esgoto sanitário como etapa prévia para a detecção de vírus e outros agentes patogênicos. Para validar a metodologia proposta, após as etapas de concentração e extração, analisaram-se a presença do ácido ribonucleico do SARS-CoV-2 (COVID-19) nas amostras, por meio de reação em cadeia da polimerase em tempo real. O ácido ribonucleico do vírus foi detectado em 80% das amostras de esgoto sanitário analisadas, comprovando o êxito do procedimento metodológico adotado. A detecção precoce de um patógeno associado ao trabalho de equipes multidisciplinares possibilita a prática da vigilância epidemiológica, que auxilia na tomada de decisões na Saúde Única — união indissociável entre a saúde animal, humana e ambiental.

ABSTRACT Sewage quality surveillance can represent a complementary tool for monitoring infectious diseases and preventing epidemic outbreaks, especially when the capacity for clinical testing is limited. Thus, the present study describes the technical details of a low-cost method for concentrating and extracting nucleic acids from sewage samples, as a preliminary step for the detection of viruses and other pathogens. To validate the proposed methodology, after the concentration and extraction steps, the presence of the SARS coronavirus-2 (COVID-19) in the samples was analyzed using real-time polymerase chain reaction. The virus’ ribonucleic acid was detected in 80% of the sewage samples analyzed, proving the success of the methodological procedure adopted. The early detection of a pathogen associated with the work of multidisciplinary teams allows the practice of epidemiological surveillance, which assists in making decisions about One Health — an inseparable union between animal, human, and environmental health.

Abstract This study assessed the performance of two pilot units, a conventional activated sludge (CAS) and an Integrated Fixed-Film Activated Sludge (IAS), in the treatment of leachate from sanitary landfill combined with domestic sewage, with the aim of removing organic substances. In order to assess the possible impacts on treatment, three experimental phases were designed using influent leachate contributions of 5%, 10%, and 20% of the total BOD load. Overall, the results showed that no significant changes in the behavior of biological processes. The IAS unit presented average BOD removal efficiencies of above 88%, 87% and 80% for the three leachate load contributions of 5%, 10% and 20% studied. The CAS unit presented lower average efficiency with a 5% leachate contribution (64%), but displayed a similar performance to the IAS unit in the other phases (82% and 80%); similar quantitative aspects were observed for both treatment processes with regards to biomass composition analysis. The kinetic coefficients related to heterotrophic metabolism did not indicate negative effects on treatment efficiency as a result of the increase in leachate addition, with values of 2.8; 2.8 and 2.7 d-1 obtained respectively for each phase with the CAS unit, and 2.0; 1.5 and 1.6 d-1 with the IAS unit, representing similar values to those found in the literature (1.5 a 5.0 d-1). The results reinforced the conclusion that the leachate load introduced did not cause inhibition or significant alterations to heterotrophic metabolism, and, therefore, to the removal of organic matter.

RESUMO Este trabalho teve como objetivo a determinação dos parâmetros cinéticos que descrevem o crescimento das bactérias heterotróficas e autotróficas nitrificantes em três sistemas de lodos ativados com aeração prolongada, operados com baixa aeração, a fim de se obter a remoção de nitrogênio de esgoto sanitário pelo processo de nitrificação e desnitrificação simultâneas (NDS). Em relação às remoções de matéria orgânica e nitrogênio, aplicando-se idade do lodo na faixa de 12 a 20 dias e concentrações de oxigênio dissolvido (OD) nos reatores em torno de 0,5 mg O2.L-1, foi possível obter eficiências superiores a 90% e um esgoto tratado com concentrações de nitrato inferiores a 7,0 mg N.L-1. Os experimentos realizados comprovam que, nas condições operacionais adotadas durante os testes respirométricos, as bactérias heterotróficas e autotróficas presentes nos lodos ativados estavam ativos e, ainda que baixa, a concentração de OD não foi limitante para o desenvolvimento da cinética dos processos envolvidos na remoção de materiais orgânico e nitrogenado.

ABSTRACT The objective of this work was to determine the kinetic parameters that describe the growth of heterotrophic and autotrophic nitrifying bacteria in three systems of activated sludge with prolonged aeration, operated with low aeration, with the objective of obtaining nitrogen removal of sanitary sewage by simultaneous nitrification and denitrification (SND). In relation to the removal of organic matter and nitrogen, by using sludge ages ranging from 12 to 20 days and OD concentrations in the reactors around 0.5 mgO2.L-1, it was possible to obtain efficiencies higher than 90% and a sewer treated with nitrate concentrations below 7.0 mgN.L-1. The experiments carried out prove that, under the operating conditions adopted during the respirometric tests, heterotrophic and autotrophic bacteria present in activated sludge were active and, although the low concentration of OD was not limiting for the development of the kinetics of the processes involved in the removal of organic and nitrogenous material.

RESUMO Neste estudo, foi avaliado o desempenho de um reator em bateladas sequenciais com biofilme de leito móvel operado pelo processo anaeróbio-anóxico-óxico (A2O), aplicado à remoção simultânea de material orgânico, nitrogênio e fósforo de esgoto sanitário. Utilizaram-se dois reatores com volume útil de 36 L cada, sendo que um deles recebeu anéis plásticos móveis do tipo Kaldnes®, com área superficial específica estimada em 310 m2/m3 que ocuparam 50% do volume útil do reator (denominado aqui de MBSBBR). O estudo foi conduzido com tempo de retenção de sólidos (TRS) de 12 dias, tempo de retenção hidráulico (TRH) de 6 horas, taxa de alimento/microrganismo (A/M) de 0,4 a 0,5 gDQO/SSV.d, oxigênio dissolvido (OD) na faixa de 0,3-0,8 mgO2/L e taxas de aplicação de carga orgânica, nitrogênio e fósforo de 47,2 gDQO/L.d, 5,4 gNTK/L.d e 0,4 gP/L.d, respectivamente. Os resultados de eficiência de remoção de demanda química de oxigênio (DQO), N-NH3 e fósforo foram de 91,1, 90,5 e 85,4% para o reator MBSBBR e de 89,5, 91,6 e 84,4% para o reator RBS, respectivamente. Os resultados do teste estatístico de ANOVA foram aplicados às principais variáveis estudadas, e os valores convergiram para valores de f observado < f crítico . Dessa forma, considera-se que houve similaridade de desempenho nos reatores MBSBBR e RBS. Conclui-se que a introdução do meio suporte não trouxe benefícios ao tratamento em termos de remoção de nutrientes. No entanto, o estudo mostrou que é possível de se obter elevada remoção de nitrogênio, em baixas concentrações de OD, o que se torna vantajoso para o tratamento de esgoto com elevada concentração de nitrogênio.

ABSTRACT In this study, the performance of a reactor in sequential batch with mobile bed biofilm operated by the anaerobic-anoxic-oxic (A2O) process, applied to the simultaneous removal of organic material, nitrogen and phosphorus from sanitary sewage was evaluated. Two reactors with a useful volume of 36 liters each were used, one of them receiving Kaldnes® type mobile plastic rings, with a specific surface area estimated at 310 m2/m3, which occupied 50% of the reactor’s useful volume (MBSBBR). The study was conducted with 12-day solid retention time (SRT), 6 hour hydraulic retention time (HRT), food/microorganism (F/M) ratio of 0.4 to 0.5 gCOD/VSS.d, dissolved oxygen (DO) in the range of 0.3-0.8 mgO2/L and application rates of organic load, nitrogen and phosphorus of 47.2 gCOD/L.d, 5.4 gTNK/L.d and 0.4 gP/L.d, respectively. The efficiency of chemical oxygen demand (COD), N-NH3 and Phosphorus removal was of 91.1%, 90.5% and 85.4% for the MBSBBR reactor and 89.5%, 91.6% and 84.4% for the RBS reactor, respectively. The results of the statistical ANOVA test were applied to the main variables studied and the values converged to values of f observed < f critical . In this way, it is considered that there was a similarity of performance between the MBSBBR and RBS reactors. It is concluded that the introduction of the support medium did not bring benefits to the treatment in terms of nutrient removal. However, the study showed that it is possible to obtain high nitrogen removal at low concentrations of DO, which is advantageous for the sewage treatment with high nitrogen concentration.