Enhancing anaerobic digestion using free nitrous acid: Identifying the optimal pre-treatment condition in continuous operation.

Free Nitrous Acid (FNA) pre-treatment is a promising technology demonstrated effective in improving waste activated sludge degradability and anaerobic digestion (AD) performance. Pre-treatment conditions including FNA concentration and treatment duration determine operational and capital cost of full-scale implementation, which have not been studied in long-term experiments. The knowledge of FNA pre-treatment conditions improving the AD performance is urgently required to determine suitable conditions for the technology implementation. In this work, five different FNA concentrations (2.2, 4.4, 7.2, 12 mgN/L and nitrite only without pH adjustment) and three treatment durations (8, 24 and 48 h) were studied in four lab-scale semi-continuous AD reactors for over 300 days. FNA pre-treatment was shown under all tested conditions effective in enhancing AD performances, while its effectiveness and resulted benefits varied substantially amongst different pre-treatment conditions. The long-term experiment demonstrated that the methane production, sludge reduction and digested sludge viscosity of AD are positively correlated with the FNA concentration and durations, until an optimal condition is reached, which was identified in this work to be FNA concentration of 7.2 mgN/L and treatment duration of 24 h. Microbial community changes supported the apparent observation of enhanced sludge degradation at elevating FNA concentrations applied during pre-treatment. The short-term sludge solubilization results were inconsistent with the long-term AD performance, which was potentially caused by inhibitions from stringent FNA pre-treatment conditions applied (FNA = 12 mgN/L with 24-hour treatment & FNA = 7.2 mgN/L with 48-hour treatment). Overall, results suggested FNA pre-treatment at the optimized condition is highly beneficial to WWTPs and competitive with other pre-treatment technologies, e.g., thermal hydrolysis pre-treatment. This work comprehensively evaluated the key design parameters of FNA pre-treatment process, reached a major milestone in the development and applications of FNA technologies.

The origin of waste activated sludge affects the enhancement of anaerobic digestion by free nitrous acid pre-treatment.

Anaerobic digestion is a common stabilization method for treating primary sludge (PS) and waste activated sludge (WAS). However, its application is often limited by the degradation of WAS. Recent studies have demonstrated FNA to be an effective pre-treatment for enhancing WAS degradability, while having limited effect on PS degradability. WAS characteristics are impacted by wastewater treatment plant (WWTP) configuration and this study is the first to compare the effectiveness of FNA pre-treatment on WAS from WWTP with and without primary treatment. In this study, WAS samples were collected from four full-scale WWTPs with or without primary treatment. Sludge characterization, biomethane potential tests and mathematical modeling were conducted to assess the impacts of FNA pre-treatment on anaerobic digestion. The results showed that FNA pre-treatment was consistently effective for WAS from different WWTPs, while the extent of enhancement varied between WWTPs. For WAS from WWTPs without primary treatment, FNA pretreatment increased the rate of hydrolysis by 54-66% compared to 22-33% increase for WAS without primary treatment. In contrast, WAS from WWTPs with primary treatment experienced greater increases in methane potential (22-24%) compared to WAS from WWTPs without primary treatment (14-16%). These variances could be associated with primary treatment impacting the wastewater COD/N ratio and thus portion of extracellular polymetric substances (EPS) and cells in WAS. FNA pre-treatment targets the destruction of polymetric substances and cells, therefore WAS with a higher proportion of cells (i.e., WAS with primary treatment) experienced greater improvements in methane yield. Similarly, greater improvements in hydrolysis rate were observed for WAS from WWTP without primary sedimentation which contain higher proportions of large EPS molecules. Despite its consistent effectiveness on WAS samples, FNA pre-treatment was ineffective for improving the digestibility of high-rate activated sludge (HRAS).

An integrated strategy to enhance performance of anaerobic digestion of waste activated sludge.

Anaerobic digestion (AD) is an essential process in wastewater treatment plants as it can reduce the amount of waste activated sludge (WAS) for disposal, and also enables the recovery of bioenergy (i.e. methane). Here, a new pretreatment method to enhance anaerobic digestion was achieved by treating thickened WAS (TWAS) with ferric (as FeCl3) and nitrite simultaneously for 24-hour at room temperature. Biochemical methane potential tests showed markedly improved degradability in the pretreated TWAS, with a relative increase in hydrolysis rate by 30%. A comparative experiment with the operation of two continuous-flow anaerobic digesters further demonstrated the improvement in biogas quantity and quality, digestate disposal, and phosphorus recovery in the experimental digester. The dosed FeCl3 (i.e. ~6 mM) decreased the pH of TWAS to ~5, which led to the formation of free nitrous acid (FNA, HNO2) at parts per million levels (i.e. ~6 mg N/L), after dosing nitrite at 250 mg NO2--N/L. This FNA treatment caused a 26% increase in methane yield and volatile solids destruction, 55% reduction in the viscosity of sludge in digester, and 24% less polymer required in further digestate dewatering. In addition, the dosed Fe(III) was reduced to Fe(II) which precipitated sulfide and phosphorus, leading to decreased hydrogen sulfide concentration in biogas, and increased percentage of vivianite in the total crystalline iron species in digested sludge. Our study experimentally demonstrated that combined dosing of FeCl3 and nitrite is a useful pretreatment strategy for improving anaerobic digestion of WAS.

Robust Nitritation Sustained by Acid-Tolerant Ammonia-Oxidizing Bacteria.

Oxidation of ammonium to nitrite rather than nitrate, i.e., nitritation, is critical for autotrophic nitrogen removal. This study demonstrates a robust nitritation process in treating low-strength wastewater, obtained from a mixture of real mainstream sewage with sidestream anaerobic digestion liquor. This is achieved through cultivating acid-tolerant ammonia-oxidizing bacteria (AOB) in a laboratory nitrifying bioreactor at pH 4.5-5.0. It was shown that nitrite accumulation with a high NO2-/(NO2- + NO3-) ratio of 95 ± 5% was stably maintained for more than 300 days, and the obtained volumetric NH4+ removal rate (i.e., 188 ± 14 mg N L-1 d-1) was practically useful. 16S rRNA gene sequencing analyses indicated the dominance of new AOB, "Candidatus Nitrosoglobus," in the nitrifying guild (i.e., 1.90 ± 0.08% in the total community), with the disappearance of typical activated sludge nitrifying microorganisms, including Nitrosomonas, Nitrospira, and Nitrobacter. This is the first identification of Ca. Nitrosoglobus as key ammonia oxidizers in a wastewater treatment system. It was found that Ca. Nitrosoglobus can tolerate low pH (<5.0), and free nitrous acid (FNA) at levels that inhibit AOB and nitrite-oxidizing bacteria (NOB) commonly found in wastewater treatment processes. The in situ inhibition of NOB leads to accumulation of nitrite (NO2-), which along with protons (H+) also produced in ammonium oxidation generates and sustains FNA at 3.0 ± 1.4 mg HNO2-N L-1. As such, robust PN was achieved under acidic conditions, with a complete absence of NOB. Compared to previous nitritation systems, this acidic nitritation process is featured by a higher nitric oxide (NO) but a lower nitrous oxide (N2O) emission level, with the emission factors estimated at 1.57 ± 0.08 and 0.57 ± 0.03%, respectively, of influent ammonium nitrogen load.

Consenso colombiano de expertos sobre recomendaciones informadas en la evidencia para la prevención, el diagnóstico y el manejo de la lesión renal aguda por SARS-CoV-2/COVID-19 / Colombian consensus of experts on recommendations informed in the evidence for the prevention, diagnosis and management of acute kidney injury by SARS-CoV-2/COVID-19

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Abstract Introduction: Acute kidney injury is a frequent complication in patients with COVID-19 and its occurrence is a potential indicator of multi-organ dysfunction and disease severity. Objective: Develop, through an expert consensus, evidence-based recommendations for the prevention, diagnosis, and management of acute kidney injury in patients with SARS CoV2 / COVID-19 infection. Materials and methods: Based on a rapid systematic review in Embase and Pubmed databases and documents from scientific societies, we made preliminary recommendations and consulted with an expert group through an online tool. Then we defined agreement after at least 70 % consensus approval. Quality evidence was evaluated according to the type of document included. The strength of the recommendations was graded as strong or weak. Results: Fifty clinical experts declared their conflict of interest; the consultation took place between May 2 and 29, 2020. The range of agreement ranged from 75.5 % to 100 %. Recommendations for prevention, diagnosis and management of acute kidney injury in patients with SARS CoV2 infection are presented. Conclusions: Although the good quality information available regarding acute kidney injury in patients with COVID-19 is scarce, the recommendations of clinical experts will guide clinical decision-making and strategies around patients with this complication, guaranteeing care focused on the people, with high quality standards, and the generation of safety, health and wellness policies for multidisciplinary care teams.

Consenso colombiano de expertos sobre recomendaciones informadas en la evidencia para la prevención, el diagnóstico y el manejo de la infección por SARS-CoV-2/COVID-19 en pacientes con Enfermedad Renal Crónica en diálisis / Colombian Expert Consensus on Evidence-Informed Recommendations for the Prevention, Diagnosis, and Management of SARS-CoV-2 / COVID-19 Infection in Patients with Chronic Kidney Disease on Dialysis

Resumen Introducción: Las personas con diálisis de mantenimiento se consideran una población en alto riesgo de infección por SARS-CoV-2, complicaciones y muerte. La periodicidad de la diálisis, la organización y la demanda en las unidades de diálisis y las limitaciones de alfabetización en salud poblacional limitan el cumplimiento del aislamiento y el distanciamiento social. Objetivo: Desarrollar, mediante un consenso de expertos, recomendaciones informadas en evidencia para la prevención, el diagnóstico y el manejo de la infección por SARS-CoV-2/COVID-19 en pacientes con enfermedad renal crónica. Materiales y métodos: Se realizó una revisión rápida de literatura en Pubmed, Embase y sociedades científicas. La calidad de evidencia fue evaluada según el tipo de estudio incluido. El acuerdo se definió para cada recomendación con umbral de al menos 70% de aprobación. La fuerza de las recomendaciones fue graduada como fuerte o débil. Resultados: El colectivo fue consultado entre el 17 y 19 de mayo de 2020. Se obtuvo respuesta de 44 expertos clínicos que declararon conflicto de interés previo a la consulta. El acuerdo de las recomendaciones estuvo entre 70,5 y 100%. Se presentan las recomendaciones de un colectivo experto para la prevención, el diagnóstico y el manejo de infección por SARS-CoV-2/COVID-19 en pacientes con enfermedad renal crónica. Conclusión: Debido a la reciente aparición de la infección por SARS-CoV-2 y las incertidumbres respecto a la prevención, el diagnóstico y el manejo, las recomendaciones presentadas se conciben como un estándar colombiano que permita garantizar un cuidado centrado en las personas con enfermedad renal crónica y la protección de los profesionales de la salud.

Abstract Introduction: People with chronic dialysis are considered a population at high risk of SARS CoV2 infection and its derived complications and death. The need to go to strict dialysis schedules, the high demand in the kidney facilities and the difficulties derived from the time and space organization in the rooms in the face to the pandemic added to the difficult learning, teaching and adapting new protocols manifest the needed of standard recommendation according to this problem in people who couldn't have an ideal isolation. Objective: Develop through an expert consensus, evidence-informed recommendations for the prevention, diagnosis, and management of SARS-CoV-2/COVID-19 infection in patients with chronic kidney disease on Dialysis. Materials and methods: We carried out a quick literature review, PubMed, Embase and scientific societies were consulted. The quality of the evidence was considered according to the type of study included. The agreement threshold defined for each recommendation was > 70% approval among experts. The strength of the recommendations was rated as strong or weak. Results: Between May 17 and 19, 2020, was conformed a team of 44 clinical experts who declared their interest conflict prior to the consultation. The agreement of the recommendations was between 70.5% and 100%. The recommendations were separated in prevention, early identification, and diagnostic, isolation in hemodialysis facilities and peritoneal dialysis, and team protection. Ethical considerations also were included. Conclusion: Due to the recent appearance of SARS-CoV-2 infection and the uncertainties regarding prevention, diagnosis and management, the recommendations presented are conceived as a Colombian standard that allows guaranteeing focused care for people with chronic kidney disease and the protection of health team.

Comunicación intercultural en la transmisión de conocimientos, saberes y prácticas culturales de la medicina tradicional en el pueblo mestizo costeño de Siuna / Intercultural communication in the knowledge transmission, traditional medicine knowigns and cultural practices in the coastal mestizo people from Siuna

El Cultivo y Crianza de Sabidurías y conocimientos "Comunicación Intercultural en la transmisión de Conocimientos, saberes y prácticas culturales de la medicina tradicional en el pueblo mestizo costeño de Siuna, RACCN", se realizó bajo el paradigma cualitativo, con enfoque etnometodológico e interaccionismo simbólico. Cada uno de los datos obtenidos son el resultado del proceso de convivencia y conversaciones con abuelos, abuelas, curanderos, curanderas, parteras y sobadores, se visibilizan conocimientos, saberes y prácticas culturales de la medicina tradicional del pueblo mestizo para el cuido de la salud durante las etapas más importantes de la vida del ser humano. Asimismo, se describen las prácticas de comunicación propia en la transmisión de esta herencia cultural, se evidencia la oralidad a través del diálogo intergeneracional, se reconoce el papel de la mujer en estos procesos dinámicos de comunicación y conocimientos, desde el roll que desempeña en la comunidad y la familia, donde abuelas y madres son las guardianas del bienestar familiar.

Organizational Wellness Program Implementation and Evaluation: A Holistic Approach to Improve the Wellbeing of Middle Managers.

: Employee wellness programs can provide benefits to institutions as well as employees and their families. Despite the attempts of some organizations to implement programs that take a holistic approach to improve physical, mental, and social wellness, the most common programs are exclusively comprised of physical and nutritional components. In this study, we implemented a wellness program intervention, including training using a holistic approach to improve the wellbeing of middle managers in several multinational organizations. We included control and experimental groups to measure wellness and teamwork with two repeated measures. Our results indicated that employees receiving the intervention had improved measures of wellness and teamwork. A positive relationship was found between wellness and teamwork in the experimental group when compared with the control group. Taken together, the data suggest that implementation of these programs would provide valuable outcomes for both employees and organizations.

Reacción de los padres ante la comunicación del diagnóstico de un hijo con síndrome de down / Parent’s reaction to the communication of the diagnosis of a child with down syndrome

El síndrome de Down es una entidad clínico-genética cuyo impacto familiar tiene su origen desde la notificación del diagnóstico. La manera como se imparta esta noticia y el afrontamiento por parte de los padres pueden definir la aceptación del niño con esta condición. Objetivo: Evaluar las circunstancias de notificación del diagnóstico del síndrome de Down y precisar las actitudes, reacciones, conocimiento y preocupaciones de los padres, en relación a la condición de su hijo. Pacientes y Métodos: Se realizó un estudio observacional, descriptivo y transversal, en el cual se aplicó una encuesta validada previamente por expertos, a 30 padres cuyos hijos presentan el diagnóstico de síndrome de Down. Resultados: El diagnóstico de síndrome de Down se realizó en etapa postnatal en 93,33% de los casos. El escenario de comunicación del diagnóstico fue en un ambiente tranquilo y privado en 86,67%, con participación de las madres con bebé en brazos en 76,67%. Ante la noticia, se identificó 60% de apoyo de la pareja y 66,67% del grupo familiar. Discusión y conclusión: La notificación del diagnóstico del síndrome de Down a los padres cumple en la mayoría de los casos con las condiciones ideales descritas en la literatura. Se debe promover el diagnóstico prenatal en aquellas embarazadas con riesgo de tener hijos con síndrome de Down, para que se promueva una aceptación temprana y lograr el apoyo familiar y médico adecuado.

Down syndrome is a clinical and genetic entity whose family impact originates from the notification of the diagnosis. The way in which this notice takes place and coping by parents can define the acceptance of children with this condition. Objective: To evaluate the circumstances of notify the diagnosis of Down syndrome and clarify the attitudes, reactions, knowledge and concerns of parents regarding their child's condition. Patients and Methods: A descriptive, observational and transversal study, in which a poll previously validated by experts was, applied 30 parents whose children have diagnosis of Down syndrome. Results: The diagnosis of Down syndrome was performed in postnatal stage in 93,33% of cases. The communication scenario of diagnosis was in a quiet and private environment in 86,67%, with participation of mothers with baby in arms in 76,67%. At the notice were identified 60% of partner support and 66,67% of the group family. Discussion and conclusion: Notification diagnosis of Down syndrome to parents comply in most cases with the ideal conditions described in the literature. Should promote prenatal diagnosis in those pregnancies at risk of having children with Down syndrome, early acceptance to be promoted and achieve family support and adequate medical.

Efecto de la frecuencia léxica y silábica en afasia anómica / Effect of lexical and syllable frequency in anomic aphasia / Efeito da frequência lexical e silábica em afasia anómica

Objetivo: este estudio compara el desempeño de dos grupos de participantes con y sin afasia anómica en tareas de decisión léxica (TDL) y de deletreo en relación con el efecto de las variables de frecuencia léxica y silábica. Materiales y métodos: se realizó un estudio prospectivo con un diseño 2x2x2, donde se administraron la TDL, en la cual cada participante debía decidir si el estímulo presentado correspondía a palabra o pseudopalabra y la tarea de deletreo, donde los participantes debían deletrear de forma oral cada una de las palabras presentadas auditivamente. Resultados: para la TDL, el grupo experimental presentó mayor porcentaje de error en los estímulos de alta frecuencia silábica, mientras que el control tuvo más errores en aquellos de baja frecuencia silábica. En cuanto a los tiempos de reacción, el grupo experimental tardó más que los controles en resolver la tarea. La tarea de deletreo no mostró diferencia de ejecución por grupos ni condiciones (frecuencia léxica y silábica). Conclusiones: los resultados del presente estudio demuestran el efecto de facilitación de la frecuencia léxica y la inhibición que genera la frecuencia silábica alta, ampliamente soportada por la investigación en población normatizada mediante diferentes lenguajes.

Objective: this study compares the performance of two groups of participants with and without aphasia anomic in a lexical decision tasks (LDT) and spelling, in relation to the effect of the variables of word frequency and syllable. Materials and methods: a prospective study with a 2x2x2 design, which administered the LDT, in which each she/he had to decide if it was a real Spanish word or not, pressing one of two keys. To the task of spelling, they had to spell orally each of words presented auditorily. Results: It was found that in the LTD, the experimental group made more errors in the high-frequency stimuli syllable while the control group had more errors in the low-frequency syllables. In terms of reaction times was evident that the experimental group took longer to solve the task than the control group. The spelling task performance showed no difference in groups or conditions (lexical frequency and syllable). Conclusions: similar than other researches in normalized population, the results of this study demonstrate the effect of lexical frequency facilitation and inhibition that generates high syllable frequency.

Objetivo: este estudo compara o desempenho de dois grupos de participantes com e sem afasia anómica em tarefas de decisão lexical (TDL) e de soletração em relação com o efeito das variáveis de frequência lexical e silábica. Materiais e métodos: realizou-se um estudo prospectivo com um plano 2x2x2, onde se administraram a TDL, e cada participante devia decidir se o estímulo apresentado correspondia a palavra ou pseudopalavra e a tarefa de soletração, onde os participantes deviam soletrar de forma oral cada uma das palavras apresentadas auditivamente. Resultados: para a TDL, o grupo experimental apresentou maior porcentagem de erro nos estímulos de alta frequência silábica, enquanto o controle teve mais erros naqueles de baixa frequência silábica. Com relação aos tempos de reação, o grupo experimental tardou mais que os controles em resolver a tarefa. A tarefa de soletração não mostrou diferença de execução por grupos nem condições (frequência lexical e silábica). Conclusões: os resultados do presente estudo demonstram o efeito de facilitação da frequência lexical e a inibição que gera a frequência silábica alta, amplamente suportada pela pesquisa em população normatizada mediante diferentes linguagens.