[en] Swine production generates large volumes of wastewater, rich in organic matter, nutrients and pathogens. Electrodisinfection is used to remove organic matter and nutrients from animal wastewater, but its effectiveness on pathogens inactivation has not been studied using real swine wastewater. Therefore, we evaluated the efficiency of electrodisinfection on pathogens reduction using real swine wastewater. For that, we tested the effect of pH and current density, using iron and aluminum electrodes. Results show a 99.99% reduction of Escherichia coli when electrodisinfection was performed during 60 min at pH 3.0 and current density of 44 mA cm⁻² using iron or aluminum electrodes. The liquid fraction obtained after electrodisinfection can be reused for cleaning swine buildings, thus avoiding the use of potable water.

[en] The 2015 rupture of the Fundão dam near the district of Bento Rodrigues in Mariana, Minas Gerais, Brazil, released around 50 million m³ of iron ore tailings. The first tributary of the Rio Doceto receive this waste was the Gualaxo do Norte River. Many groups in Brazil and from around the world have studied the environmental and social impacts of this disaster. However, relationships between the introduction of mining waste, the geological complexity of the area, and the presence of pathogenic organisms have not yet been investigated. The present study aimed to measure the concentrations of enteric pathogens along the Gualaxo do Norte River after the environmental disaster and to correlate their abundance with the presence of metals and semimetals coming from both mining tailings and geological sources. For this purpose, we collected water samples from 27 stations along the entire basin during a hydrological year. The concentrations of metals and semimetals measured in this study were generally within limits established by national and international legislation, except for those of iron and manganese. Positive correlations between the human adenovirus (HAdV) and arsenic, barium, iron, lead, manganese, and nickel were confirmed, allowing us to observe that there is an abundance of the potentially infectious virus present in the studied sites containing metal/semimetal concentrations. These studies indicate the importance of investigations that consider viral enteric pathogens complexed with metals and may favor the stability and prolongation of the infectivity of such pathogens in water destined for human and animal usage.

[en] Phycoremediation of swine wastewater is an attractive treatment to remove contaminants and simultaneously produce valuable feedstock biomass. However, there is a lack of information about the application of phycoremediation on veterinary antibiotic removal. Thus, this research investigated the degradation of tetracycline, oxytetracycline, chlortetracycline and doxycycline in swine wastewater treated with phycoremediation. The tetracyclines degradation kinetics was adjusted to the pseudo-first-order kinetics model, with kinetic constant k₁ in the following: 0.36 > 0.27>0.19 > 0.18 (d⁻¹) for tetracycline, doxycycline, oxytetracycline and chlortetracycline, respectively. The maximum concentration of microalgae biomass (342.4 ± 20.3 mg L⁻¹) was obtained after 11 days of cultivation, when tetracycline was completely removed. Chlortetracycline concentration decreased, generating iso-chlortetracycline and 4-epi-iso-chlortetracycline. Microalgae biomass harvested after antibiotics removal presented a carbohydrate-rich content of 52.7 ± 8.1, 50.1 ± 3.3, 51.4 ± 5.4 and 57.4 ± 10.4 (%) when cultured with tetracycline, oxytetracycline, chlortetracycline and doxycycline, respectively, while the control culture without antibiotics presented a carbohydrate content of 40 ± 6.5%. These results indicate that could be a valuable source for bioenergy conversion.

[en] The safe recycling of organic wastes such as the nutrients obtained from agriculture activities is a relevant aspect of the “One Health” strategy, a worldwide initiative including all aspects of health care for humans and animals, as well as aspects related to the conservation and development of the environment. It represents an important opportunity to mitigate the potential impact of microbial pathogens likely present in nutrient natural sources, as digestate, when applied to land as fertilizers. The objectives of the current study were to determine the inactivation of enteric microorganisms in swine digestate (effluent and sludge) during storage in anaerobic conditions and at different ambient temperatures of tropical zones (16, 22, and 37 °C). Human adenovirus 2 (HAdV-2), bacteriophage PhiX-174, and Salmonella enterica serovar typhimurium (S. typhimurium) were used as enteric microbial models to determine the minimum storage time required to reduce at least 3log of enteric microorganisms load in both matrices at the mentioned temperatures. The minimum storage time required for S. typhimurium was shorter than those observed for viruses at 37 °C, while reduction of at least 3log for S. typhimurium was observed after just 1 day; 20 and 90 days were needed for similar reductions for HAdV-2 and PhiX-174, respectively. Similar results were also observed at lower temperatures: 30 and 45 days were needed for S. typhimurium at 22 and 16 °C, respectively, but 30 and 90 days were needed at 22 °C for HAdV-2 PhiX-174, respectively, or 90 and 120 days at 16 °C for HAdV-2 PhiX-174, respectively. This is a pioneering study on the evaluation of inactivation of enteric viruses in swine digestate in usual tropical ambient temperatures; it demonstrates that the time for a considerable inactivation is longer than that observed for a enteric microorganisms (S. typhimurium), and shows that the storage of swine digestate at the referred temperatures can be used as a low-cost post-treatment to inactivate enteric microorganisms, allowing a further use as safer fertilizer.