• Energy Research

Rainwater is conventionally perceived as an alternative drinking water source, mostly needed to meet water demand under particular circumstances, including under semi-arid conditions and on small islands. More recently, rainwater has been identified as a potential source of clean drinking water in cases where groundwater sources contain high concentrations of toxic geogenic contaminants. Specifically, this approach motivated the introduction of the Kilimanjaro Concept (KC) to supply fluoride-free water to the population of the East African Rift Valley (EARV). Clean harvested rainwater can either be used directly as a source of drinking water or blended with polluted natural water to meet drinking water guidelines. Current efforts towards the implementation of the KC in the EARV are demonstrating that harvesting rainwater is a potential universal solution to cover ever-increasing water demands while limiting adverse environmental impacts such as groundwater depletion and flooding. Indeed, all surface and subsurface water resources are replenished by precipitation (dew, hail, rain, and snow), with rainfall being the main source and major component of the hydrological cycle. Thus, rainwater harvesting systems entailing carefully harvesting, storing, and transporting rainwater are suitable solutions for water supply as long as rain falls on earth. Besides its direct use, rainwater can be infiltrating into the subsurface when and where it falls, thereby increasing aquifer recharge while minimizing soil erosion and limiting floods. The present paper presents an extension of the original KC by incorporating Chinese experience to demonstrate the universal applicability of the KC for water management, including the provision of clean water for decentralized communities.

Rainwater is conventionally perceived as an alternative drinking water source, mostly needed to meet water demand under particular circumstances, including under semi-arid conditions and on small islands. More recently, rainwater has been identified as a potential source of clean drinking water in cases where groundwater sources contain high concentrations of toxic geogenic contaminants. Specifically, this approach motivated the introduction of the Kilimanjaro Concept (KC) to supply fluoride-free water to the population of the East African Rift Valley (EARV). Clean harvested rainwater can either be used directly as a source of drinking water or blended with polluted natural water to meet drinking water guidelines. Current efforts towards the implementation of the KC in the EARV are demonstrating that harvesting rainwater is a potential universal solution to cover ever-increasing water demands while limiting adverse environmental impacts such as groundwater depletion and flooding. Indeed, all surface and subsurface water resources are replenished by precipitation (dew, hail, rain, and snow), with rainfall being the main source and major component of the hydrological cycle. Thus, rainwater harvesting systems entailing carefully harvesting, storing, and transporting rainwater are suitable solutions for water supply as long as rain falls on earth. Besides its direct use, rainwater can be infiltrating into the subsurface when and where it falls, thereby increasing aquifer recharge while minimizing soil erosion and limiting floods. The present paper presents an extension of the original KC by incorporating Chinese experience to demonstrate the universal applicability of the KC for water management, including the provision of clean water for decentralized communities.

Rainwater harvesting (RWH) is generally perceived as a promising cost-effective alternative water resource for potable and non-potable uses (water augmentation) and for reducing flood risks. The performance of RWH systems has been evaluated for various purposes over the past few decades. These systems certainly provide economic, environmental, and technological benefits of water uses. However, regarding RWH just as an effective alternative water supply to deal with the water scarcity is a mistake. The present communication advocates for a systematic RWH and partial infiltration wherever and whenever rain falls. By doing so, the detrimental effects of flooding are reduced, groundwater is recharged, water for agriculture and livestock is stored, and conventional water sources are saved. In other words, RWH should be at the heart of water management worldwide. The realization of this goal is easy even under low-resource situations, as infiltration pits and small dams can be constructed with local skills and materials.

Rainwater harvesting (RWH) is generally perceived as a promising cost-effective alternative water resource for potable and non-potable uses (water augmentation) and for reducing flood risks. The performance of RWH systems has been evaluated for various purposes over the past few decades. These systems certainly provide economic, environmental, and technological benefits of water uses. However, regarding RWH just as an effective alternative water supply to deal with the water scarcity is a mistake. The present communication advocates for a systematic RWH and partial infiltration wherever and whenever rain falls. By doing so, the detrimental effects of flooding are reduced, groundwater is recharged, water for agriculture and livestock is stored, and conventional water sources are saved. In other words, RWH should be at the heart of water management worldwide. The realization of this goal is easy even under low-resource situations, as infiltration pits and small dams can be constructed with local skills and materials.

In this study, a fuzzy-based indexing approach (FIA) is developed based on a conceptual framework regarding social, environmental, economic, and technical dimensions to evaluate the overall sustainability potential of existing septic systems (SSs) of around 200 Tanzanian residential buildings in Mwanza city. FIA required the following six steps: selecting, measuring, normalizing, weighting, and aggregating the sustainability indicators (SIs) or dimensions, as well as interpretation of the indices similarly to conventional sustainability indices to aggregate the four sustainability dimensions. In total, 18 SIs were selected based on a literature review. Input data obtained for each indicator were from the social survey and laboratory analysis. The results showed that the entire SSs in the city had a general sustainability index (GSI) of 0.42. The index fell on the verge of the “danger” category, indicating that corrective measures are needed. In conclusion, FIA is simple and transparent, it provides a both theoretical and practical basis for sustainability evaluation, does not require vast quantities of data, and does not demand an advanced computer software package. Moreover, FIA is a proper method to evaluate and improve SS sustainability in the city or provide the information to decision makers, designers, and researchers to scrutinize the decision possibilities in a multidimensional manner.

In this study, a fuzzy-based indexing approach (FIA) is developed based on a conceptual framework regarding social, environmental, economic, and technical dimensions to evaluate the overall sustainability potential of existing septic systems (SSs) of around 200 Tanzanian residential buildings in Mwanza city. FIA required the following six steps: selecting, measuring, normalizing, weighting, and aggregating the sustainability indicators (SIs) or dimensions, as well as interpretation of the indices similarly to conventional sustainability indices to aggregate the four sustainability dimensions. In total, 18 SIs were selected based on a literature review. Input data obtained for each indicator were from the social survey and laboratory analysis. The results showed that the entire SSs in the city had a general sustainability index (GSI) of 0.42. The index fell on the verge of the “danger” category, indicating that corrective measures are needed. In conclusion, FIA is simple and transparent, it provides a both theoretical and practical basis for sustainability evaluation, does not require vast quantities of data, and does not demand an advanced computer software package. Moreover, FIA is a proper method to evaluate and improve SS sustainability in the city or provide the information to decision makers, designers, and researchers to scrutinize the decision possibilities in a multidimensional manner.