ABSTRACT
Most wastewater treatment facilities are built using procedures from previous designs which are predominantly from sites and regions not located at high elevation. Recognizing this limitation, we assessed the effects of elevation above sea level on the suitability of process configurations and technologies as well as their associated energy costs. Using the International Water Association (IWA) benchmark simulation model No. 2 (modified Ludzack-Ettinger process layout) as a reference, we simulated scenarios including different activated sludge process configurations, operating under different environmental and process conditions. In order to include a wide sample of environmental conditions, data on atmospheric pressure, wastewater temperature, air temperature, and relative humidity (for average, warmest, and coldest months) were collected from municipal wastewater treatment plants located at different latitudes and elevations. The results confirm that elevation is a driver against the selection of diffused aeration technologies. Aeration costs for aerobic wastewater treatment are highly influenced by local project conditions, particularly by elevation and wastewater temperature, which together influence the driving force for oxygen transfer into water. When the driving force is low, operating costs are high. Recommendations for designing treatment processes effectively, including diffused aeration systems operating at high elevations above sea level, are proposed.
Subject(s)
Waste Disposal, Fluid , Water Purification , Bioreactors , Oxygen , Sewage , WastewaterABSTRACT
La pandemia del SARS-CoV 2 es uno de los eventos en salud pública más relevantes de los últimos años, sus efectos se han traducido en millones de casos de contagios, en más de 430.000 fallecimientos y en un aumento en la necesidad de camas de cuidados intensivos alrededor del mundo. En ese contexto, se ha presentado una reducción significativa de la actividad de donación y trasplantes en varios países, y Colombia no ha sido ajena a ese fenómeno. El presente artículo, pretende dar al lector una perspectiva del estado actual de la donación y trasplantes en el mundo y en Colombia, así como plantear algunos retos que genera la pandemia del SARS-CoV 2 para la ejecución segura del proceso de donación y trasplantes en países con recursos humanos, financieros y de infraestructura limitados.
The SARS-CoV 2 outbreak is one of the most important events of public health around the world; this disease has affected millions of people, has killed over 430.000 people and has increased the needed of intensive care unit beds around the world. During the pandemic the world has seen a decline in the organ donation and transplantation activities, Colombian transplant model has been affected too. This paper wants to show the current situation of organ donation and transplantation during SARS-CoV 2 pandemic and explore some dilemmas around organ donation and transplantation for emerging countries.
