Improving environmental sanitation, health, and well-being: a conceptual framework for integral interventions.

We introduce a conceptual framework for improving health and environmental sanitation in urban and peri-urban areas using an approach combining health, ecological, and socioeconomic and cultural assessments. The framework takes into account the three main components: i) health status, ii) physical environment, and iii) socioeconomic and cultural environment. Information on each of these three components can be obtained by using standard disciplinary methods and an innovative combination of these methods. In this way, analyses lead to extended characterization of health, ecological, and social risks while allowing the comprehensive identification of critical control points (CCPs) in relation to biomedical, epidemiological, ecological, and socioeconomic and cultural factors. The proposed concept complements the conventional CCP approach by including an actor perspective that considers vulnerability to risk and patterns of resilience. Interventions deriving from the comprehensive analysis consider biomedical, engineering, and social science perspectives, or a combination of them. By this way, the proposed framework jointly addresses health and environmental sanitation improvements, and recovery and reuse of natural resources. Moreover, interventions encompass not only technical solutions but also behavioral, social, and institutional changes which are derived from the identified resilience patterns. The interventions are assessed with regards to their potential to eliminate or reduce specific risk factors and vulnerability, enhance health status, and assure equity. The framework is conceptualized and validated for the context of urban and peri-urban settings in developing countries focusing on waste, such as excreta, wastewater, and solid waste, their influence on food quality, and their related pathogens, nutrients, and chemical pollutants.

An approach to optimise nutrient management in environmental sanitation systems despite limited data.

The material flow analysis method can be used to assess the impact of environmental sanitation systems on resource consumption and environmental pollution. However, given the limited access to reliable data, application of this data-intensive method in developing countries may be difficult. This paper presents an approach allowing to develop material flow models despite limited data availability. Application of an iterative procedure is of key importance: model parameter values should first be assessed on the basis of a literature review and by eliciting expert judgement. If model outputs are not plausible, sensitive input parameters should be reassessed more accurately. Moreover, model parameters can be expressed as probability distributions and variable uncertainty estimated by using Monte Carlo simulation. The impact of environmental sanitation systems on the phosphorus load discharged into surface water in Hanoi, Vietnam, is simulated by applying the proposed approach.

Optimising water and phosphorus management in the urban environmental sanitation system of Hanoi, Vietnam.

Many areas in the world face clean water scarcity problems and phosphorus reserves are likely to be depleted in the near future. Still, a large amount of clean water is used to transport excreta through sewer systems. Most of the wastewater generated worldwide is discharged untreated into aquatic systems and leads to water pollution and loss of valuable nutrients. In Hanoi, Vietnam's capital city, high population and economic growth as well as industrialisation have led to a decrease in groundwater level and to serious river and lake pollution. A probabilistic model, simulating the impact of measures on groundwater abstraction and nutrient recovery, was used to determine the impact of policy changes in Hanoi. The results obtained reveal that harmonising environmental sanitation and agricultural systems with one another will considerably increase nutrient recovery for food production, lower expenditure for artificial fertilisers and reduce the nutrient load into the environment. The model can be applied in urban areas of developing countries to assist in the design of environmental sanitation concepts.

Assessing nutrient flows in septic tanks by eliciting expert judgement: a promising method in the context of developing countries.

Simple models based on the physical and biochemical processes occurring in septic tanks, pit and urine diversion latrines were developed to determine the nutrient flows in these systems. Nitrogen and phosphorus separation in different output materials from these on-site sanitation installations were thus determined. Moreover, nutrient separation in septic tanks was also assessed through literature values and by eliciting expert judgement. Use of formal expert elicitation technique proved to be effective, particularly in the context of developing countries where data is often scarce but expert judgement readily available. In Vietnam, only 5-14% and 11-27% of the nitrogen and phosphorus input, respectively, are removed from septic tanks with the faecal sludge. The remaining fraction leaves the tank via the liquid effluent. Unlike septic tanks, urine diversion latrines allow to immobilize most of the nutrients either in form of stored urine or dehydrated faecal matter. These latrines thus contribute to reducing the nutrient load in the environment and lowering consumption of energy and non-renewable resources for fertiliser production.

Cuando los tanques sépticos estan llenos: el desafío del manejo y tratamiento de lodos fecales

En los centros urbanos de países industrializados, la mayoría de las casas dispone de sistemas de saneamiento in situ, tales como tanques sépticos y excusados sin drenaje. Los lodos fecales recogidos generalmente son descargados sin tratamiento. Al contrario del manejo de aguas residuales, el desarrollo de estrategias para el tratamiento de lodos fecales en las condiciones prevalecuentes en países en desarrollo, ha sido muy descuidado. Los autores describen la situación al respecto, discuten los puntos clave y presentan opciones de tratamiento que resultarían sostenibles en los países de industrialización intermedia

Lagunas de estabilización para descarga de líquidos de camiones atmosféricos

El objetivo del trabajo es estudiar la factibilidad del uso de lagunas como tratamiento previo en un sistema en el que se tratan en forma conjunta líquidos cloacales y descargas de camiones atmosféricos y determinar la posibilidad de usar las lagunas del tratamiento previo como lagunas de evaporación de lodos. Los objetivos más específicos son, determinar la calidad de los lodos generados en las lagunas para descarga de camiones, encontrar tiempos y profundidades óptimas de secado, y determinar la eficiencia en remoción de bacterias coliformes y huevos de helmintos

Cuando los tanques sépticos estan llenos: el desafío del manejo y tratamiento de lodos fecales

En los centros urbanos de países industrializados, la mayoría de las casas dispone de sistemas de saneamiento in situ, tales como tanques sépticos y excusados sin drenaje. Los lodos fecales recogidos generalmente son descargados sin tratamiento. Al contrario del manejo de aguas residuales, el desarrollo de estrategias para el tratamiento de lodos fecales en las condiciones prevalecientes en países en desarrollo, ha sido muy descuidado. Los autores describen la situación al respecto, discuten los puntos clave y presentan opciones de tratamiento que resultarían sostenibles en los países de industrialización intermedia

Lagunas de estabilización para descarga de líquidos de camiones atmosféricos

El objetivo del trabajo es estudiar la factibilidad del uso de lagunas como tratamiento previo en un sistema en el que se tratan en forma conjunta líquidos cloacales y descargas de camiones atmosféricos y determinar la posibilidad de usar las lagunas del tratamiento previo como lagunas de evaporación de lodos. Los objetivos más específicos son, determinar la calidad de los lodos generados en las lagunas para descarga de camiones, encontrar tiempos y profundidades óptimas de secado, y determinar la eficiencia en remoción de bacterias coliformes y huevos de helmintos