Low voltage iron electrocoagulation as a tertiary treatment of municipal wastewater: removal of enteric pathogen indicators and antibiotic-resistant bacteria.

In this paper we analyse the feasibility of low voltage iron electrocoagulation as a means of municipal secondary effluent treatment with a focus on removal of microbial indicators, Antibiotic Resistant Bacteria (ARB) and nutrients. A laboratory scale batch unit equipped with iron electrodes was used on synthetic and real secondary effluent from a municipal wastewater treatment plant. Synthetic secondary effluent was separately assayed with spiked Escherichia coli WR1 and with bacteriophage ΦX174, while real effluent samples were screened before and after treatment for E. coli, Extended Spectrum Betalactamase-producing E. coli, Enterococci, Vancomycin Resistant Enterococci, Clostridium perfringens spores and somatic coliphages. Charge dosage (CD) and charge dosage rate (CDR) were used as the main process control parameters. Experiments with synthetic secondary effluent showed >4log10 and >5log10 removal for phage ΦX174 and for E. coli WR1, respectively. In real effluents, bacterial indicator removal exceeded 3.5log10, ARB were removed below detection limit (≥2.5log10), virus removal reached 2.3log10 and C. perfringens spore removal exceeded 2.5log10. Experiments in both real and synthetic wastewater showed that bacterial removal increased with increasing CD and decreasing CDR. Virus removal increased with increasing CD but was irresponsive to CDR. C. perfringens spore removal increased with increasing CD yet reached a removal plateau, being also irresponsive to CDR. Phosphate removal exceeded 99%, while total nitrogen and chemical oxygen demand removal were below 15% and 58%, respectively. Operational cost estimates were made for power and iron plate consumption, and were found to be in the range of 0.01 to 0.24€/m3 for the different assayed configurations. In conclusion, low voltage Fe-EC is a promising technology for pathogen reduction of secondary municipal effluents, with log10 removals comparable to those achieved by conventional disinfection methods such as chlorination, UV or ozonation.

Fat Mass Ratio in Brazilian HIV-infected Patients Under Antiretroviral Therapy and Its Relationship With Anthropometric Measurents.

INTRODUCTION: Human immunodeficiency virus-related lipodystrophy is characterized by a variety of phenotypes and metabolic changes; however, consensus has not yet been reached on its diagnostic criteria. Different cutoff values for fat mass ratio have been proposed for this specific population as an objective diagnostic criterion for lipodystrophy. This study aimed to establish sex-specific reference values for fat mass ratio and to correlate them with anthropometric measurements for the diagnosis of human immunodeficiency virus-related lipodystrophy. METHODOLOGY: A cross-sectional study was performed on 189 human immunodeficiency virus-infected patients under antiretroviral therapy. Anthropometric measurements were evaluated, and body composition was determined using dual-energy X-ray absorptiometry. Fat mass ratio was calculated as the ratio of the percentage of the trunk fat mass and the percentage of the lower limb fat mass. RESULTS: One hundred and thirty-two patients (69%) presented lipodystrophy by objective criteria. In men, the cutoff for the fat mass ratio was 1.55 (area under the receiver operating characteristic curve: 0.73 [95% confidence interval: 0.62-0.83], p = 0.000008), with a sensitivity of 62.5%, a specificity of 70.5%, a positive predictive value of 77.8%, and a negative predictive value of 53.4%. In women, the cutoff for the fat mass ratio was 0.959 (area under the receiver operating characteristic curve: 0.70 [95% confidence interval: 0.56-0.85], p = 0.03), with a sensitivity of 83.60%, a specificity of 61.5%, a positive predictive value of 90.2%, and a negative predictive value of 47.1%. Fat mass ratio was positively correlated with waist circumference (men: r = 0.246, p = 0.019; women: r = 0.302, p = 0.014) and neck circumference (men: r = 0.304, p = 0.004; women: r = 0.366, p = 0.003) in both sexes; and body mass index (r = 0.288, p = 0.006) and waist-hip ratio (r = 0.288, p = 0.006) in men. CONCLUSION: The fat mass ratio evaluated using dual-energy X-ray absorptiometry with the sex-specific cutoffs is an objective tool to define human immunodeficiency virus-related lipodystrophy.