Abstract SARS-CoV-2 is a new type of coronavirus capable to infect humans and cause the severe acute respiratory syndrome COVID-19, a disease that has been causing huge impacts across the Earth. COVID-19 patients, including mild, pre-symptomatic and asymptomatic cases, were often seen to contain infectious fragments of SARS-CoV-2 in feces and urine samples. Therefore, studies to detect the new coronavirus in wastewater, which collect and concentrate human excreta, have been extremely useful as a viral tracking tool in communities. This type of monitoring, in addition to serve as a non-invasive early warning of COVID-19 outbreaks, would provide better predictions about the SARS-CoV-2 spread and strongly contribute to maintenance the global health. Although current methods to detect viruses in wastewater, based on molecular RT-PCR and RT-qPCR techniques, were considered as reliable and provided accurate qualitative and quantitative results, they have been facing considerable challenges concerning the SARS-CoV-2 surveillance. In this review, the methods used to detect the SARS-CoV-2 in wastewater and the challenges to implement an international viral monitoring network were described. The article also addressed the emerging perspectives associated with the SARS-CoV-2 epidemiological surveillance in this environment and the importance of a worldwide collaboration to generate and disseminate the detection results.

Vegetable oils and their derivatives, like biodiesel, are used extensively throughout the world, thus posing an environmental risk when disposed. Toxicity testing using test organisms shows how these residues affect ecosystems. Toxicity tests using earthworms (Eisenia foetida. are widespread because they are a practical resource for analyzing terrestrial organisms. For phytotoxicological analysis, we used seeds of arugula (Eruca sativa and lettuce (Lactuca sativa. to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with four different periods of biodegradation in soil: zero days, 60 days, 120 days and 180 days. The studied contaminants were soybean oil (new and used) and biodiesel (B100). An evaluation of the germination of both seeds showed an increased toxicity for all contaminants as the biodegradation occurred, biodiesel being the most toxic among the contaminants. On the other hand, for the tests using earthworms, the biodiesel was the only contaminant that proved to be toxic. Therefore, the higher toxicity of the sample containing these hydrocarbons over time can be attributed to the secondary compounds formed by microbial action. Thus, we conclude that the biodegradation in soil of the studied compounds requires longer periods for the sample toxicity to be decreased with the action of microorganisms.

Uma célula eletroquímica de camada delgada foi utilizada e desenvolvida para a desinfecção de água contaminada artificialmente com Staphylococcus aureus. A eletrólise foi executada com uma fonte de corrente direta utilizando 75 mA cm-2 (3 A) ou 25 mA cm-2 (1 A). Um anodo dimensionalmente estável (DSA) de titânio revestido com uma camada do óxido de 70%TiO2 e 30%RuO2 (w/w) e distanciado por 3 milímetros de um catodo de aço inoxidável 304 foi utilizado para gerar uma camada delgada de suspensão bacteriana passando pela célula de camada delgada. As suspensões utilizadas eram feitas apenas com Na2SO4 0,08 M e livre de íons cloretos de forma a inativar as células bacterianas no tratamento eletroquímico sem a geração de cloro, este pode promover a formação dos trialometanos (THM). As taxas de fluxo em recirculação foram 200 ou 500 L h-1. A inativação do S. aureus aumentou com o tempo de eletrólise e a uma taxa de fluxo menor. Assim, a inativação de 100% para o S. aureus foi observada após 30 min a 5,6 V e 75 mA cm-2. Em 500 L h-1 e 75 mA cm-2 a inativação decresceu em três logs de unidades formadoras de colônias por mL após 60 min. O tratamento eletroquímico utilizando uma camada delgada promove a desinfecção completa de S. aureus sem a necessidade de adicionar substâncias oxidantes ou a geração de cloro.

A thin layer electrochemical cell was tested and developed for disinfection treatment of water artificially contaminated with Staphylococcus aureus. Electrolysis was performed with a low-voltage DC power source applying current densities of 75 mA cm-2(3 A) or 25 mA cm-2 (1 A). A dimensionally stable anode (DSA) of titanium coated with an oxide layer of 70%TiO2 plus 30%RuO2 (w/w) and a 3 mm from a stainless-steel 304 cathode was used in the thin layer cell. The experiments were carried out using a bacteria suspension containing 0.08 M sodium sulphate with chloridefree to determine the bacterial inactivation efficacy of the thin layer cell without the generation of chlorine. The chlorine can promote the formation of trihalomethanes (THM) that are carcinogenic. S. aureus inactivation increased with electrolysis time and lower flow rate. The flow rates used were 200 or 500 L h-1. At 500 L h-1 and 75 mA cm -2 the inactivation after 60 min was about three logs of decreasing for colony forming units by mL. However, 100% inactivation for S. aureus was observed at 5.6 V and 75 mA cm-2 after 30 min. Thus, significant disinfection levels can be achieved without adding oxidant substances or generation of chlorine in the water.

Processos convencionais de desinfecção de águas podem gerar compostos tóxicos. Esse é o caso dos trialometanos formados na reação do cloro com compostos orgânicos presentes na água. O tratamento eletrolítico pode ser um substituto à cloração com vantagem de não requer a adição de nenhum composto na água. O efeito do tratamento eletrolítico, utilizando eletrodos de carbono, na viabilidade de Bacillus subtilis foi testado para se determinar o mecanismo de morte. Através de microscopia eletrônica, foi possível evidenciar que a morte do microrganismo se deu pela lise celular, provavelmente provocada pela eletroporação irreversível da membrana celular.

Conventional processes of water disinfection can generate toxic composites. It is the case of the trihalomethanes (carcinogenic) formed in the contact of chlorine with organic substances present in the water. The electrolytic treatment can be a substitute for the chlorination process without the need for addition of chemical substances to the process. The effect of the electrolytic treatment using carbon cathode on the viability of the microorganism Bacillus subtilis was tested to determine the death process. By means of electronic microscopy, it was observed that the main cause of the microorganism's death was the cellular lysis due to the electroporation in the cell membrane.

Wastewater from a seasoning freeze-drying industry was electrolysed to increase its biodegradability. Stainless-steel electrodes were used at 9.09 A/m², for up to 80 min. Conductivity, pH, biochemical (BOD) and chemical (COD) oxygen demands, Daphnia similis acute toxicity bioassays, and bacteria counting through the plate count agar method were determined after different times of electrolysis. The results (e.g. higher BOD and lower COD) showed that the biodegradability of the wastewater was significantly increased; furthermore, Fe2+ ions liberated by the electrodes cause microorganisms to die and, when oxidised to Fe3+, contribute for the flocculation and sedimentation of solid residues.