Notas Técnicas de ECHO (TN)

Marango para Tratamiento de Auga en Emergencias - 1/3/2005

Se puede usar semillas de Moringa oleifera para tratar agua en una emergencia o situación de desastre. Estudios hechos desde los 1970 han encontrado que las semillas pueden ser altamente eficaces para remover partículas suspendidas en agua bastante a completamente turbia (las semillas tienen menos eficacia en agua poco turbia).

Las semillas de Moringa oleifera tratan agua en dos niveles. Primero, el marango funciona como coagulante. Contiene proteínas solubles en agua con carga positiva, que se amarran con partículas con carga negativa (sedimento, arcilla, bacterias, algunas toxinas, etc.). Los grumos resultantes o “flocs” se asientan (floculan) o se remueven con filtración. Segundo, el marango también parece funcionar como agente antimicrobial, aunque este aspecto sigue en estudio. Ciertas proteínas en la semilla parecen actuar como inhibidores de crecimiento de microorganismos. Los tratamientos con soluciones de marango han removido 90–99.9% de las impurezas en agua.

Polvo de Hoja de Marango - 20/1/2005

Las hojas del árbol de Moringa oleifera son muy nutritivas. Pueden consumirse frescas, cocinadas o secas. Debido a que las hojas secas del marango retienen su contenido de nutrientes, es posible convertirlas en polvo. Cuando existe una abundancia de hojas, este polvo se puede elaborar y almacenar fácilmente. El polvo de hoja de marango es un excelente suplemento nutricional y puede agregarse a cualquier platillo.

Statistical Analysis of Simple Agricultural Experiments - 1/4/2003

Use of a new crop variety or production technique may dramatically increase food production in a given area. Alternatively, an innovation successful in North America may utterly fail in the tropics. The goal of “adaptive research” is to evaluate a particular innovation for its usefulness under local conditions. This technical note is written for those who want to improve the quality of their experiments but who have little or no background in statistics. It supplements the 81st issue of ECHO Development Notes with step-by-step instructions on how to manually calculate statistics for the most commonly used experimental designs. A little persistence, very basic math skills, and perhaps a calculator are all you need to do the calculations. If you have a computer equipped with statistical software, doing a set of calculations by hand or with a calculator will help you to understand how to use the software and interpret the output. Examples are given for experiments in which only one factor (e.g. crop variety) is tested. A limited amount of statistical terminology is woven into the text for the benefit of those interested in further study.

Rope Maker - 1/1/2003

Rope can be made from cord or string or even discarded plastic bags using a simple spindle to twist the materials together. 

Acid Soils of the Tropics - 1/1/2002

Acidification of soil is a natural process with major ramifications on plant growth. As soils become more acid, particularly when the pH drops below 4.5, it becomes increasingly difficult to produce food crops. As soil pH declines, the supply of most plant nutrients decreases while aluminum and a few micronutrients become more soluble and toxic to plants. These problems are particularly acute in humid tropical regions that have been highly weathered. According to Sanchez and Logan (1992), for example, one third of the tropics, or 1.7 billion hectares, is acid enough for soluble aluminum to be toxic for most crop plants. We will look at some of the causes of acidification and list some of the expected results of both acidification and the practice of liming for acid neutralization.

What’s Inside:

• What Causes Soil to Become Acid?
• Soil pH and Aluminum
• Effects of Acidification
• Solution to the Problem
• What Happens When Soil is Limed
• Dangers of Over-Liming the Soil

Composting Toilets - 1/1/2002

A composting toilet is any system that converts human waste into compost through the natural breakdown of organic matter. The photo above shows a composting toilet from the late 1800’s. Composting toilets provide a sanitary method to recycle human waste while conserving water and protecting the environment. In addition, they produce a valuable fertilizer. Composting toilets can be divided into batch systems and continuous use systems. The models covered here are batch systems.

Papaya Leaf Tea as a Malaria Prophylactic? - 1/1/2002

ECHO does NOT recommend that anyone stop taking their antimalarial medicine in order to try this treatment. The only evidence for the effectiveness of papaya leaf tea in the prevention of malaria is anecdotal. No studies have been done to scientifically demonstrate its effectiveness.

Does papaya leaf tea prevent malaria? In ECHO Development Notes Issue 69 (September 2000), we asked if any of those in our network had heard of the use of papaya leaf tea for the treatment and/or prevention of malaria. We were prompted by a question from two development workers in Indonesia who wrote to ECHO inquiring whether papaya leaves contained quinine. They wondered because tea from the leaves is widely used there in the belief that it prevents malaria. Dr. Rolf Myhrman at Judson College analyzed the bitter leaves for quinine, but found none. That does not, of course, rule out the possibility that some other chemical in the leaves may be effective.

Should an Institution Grow its Own Food - 1/6/2001

Several times each year ECHO hears from someone (1) at an institution that is evaluating whether it should attempt to grow food for its [students, orphans, feeding program, staff, etc.] or (2) from someone contacted by such an institution and are asking ECHO's advice about whether/how to help them. Usually the institution has land that they could be farming or the government has promised to give it to them.

Digestores de Metano - 1/1/2001

Cuando el material orgánico se descompone bajo condiciones anaeróbicas, produce biogás, que es una mezcla de metano (CH4) y dióxido de carbono (CO2) con pequeñas cantidades de hidrógeno, nitrógeno, monóxido de carbono y otros componentes. El biogás puede utilizarse como fuente de combustible para cocinar, calentar, alumbrar o incluso surtir de combustible a un generador. Un digestor de metano es un dispositivo utilizado para producir y capturar este biogás. Existen muchos diseños para digestores de metano, que van desde modelos grandes y complejos hasta pequeños y sencillos. Este documento cubrirá 2 tipos principales de digestores: digestores de flujo discontinuo y digestores de flujo continuo; y 2 principales tipos de colectores de gas: colectores tubulares y colectores flotantes.

Filtro de Agua Bioarena - 1/1/2001

Los servicios inadecuados de agua potable y saneamiento resultan en un estimado de 4 mil millones de casos de
diarrea y 2.2 millones de muertes cada año (OMS/UNICEF 2000). En áreas donde no hay acceso a agua potable,
el tratamiento del agua en los hogares puede contribuir de manera significativa a reducir los problemas de salud
relacionados con el agua. Los métodos de tratamiento del agua más efectivos siguen un proceso de sedimentación,
filtración, y desinfección para eliminar bacterias, virus, helmintos y protozoarios.