Greywater tower Arba Minch, Ethiopia - Case study of sustainable sanitation projects

Content - Summary

This case study shows the use of greywater towers as a tool for household sanitation in peri-urban areas in Arba Minch, Ethiopia. The project built 9 greywater towers in private compounds that serve 47 inhabitants and coasted 180 euros. The project has been realized within the ROSA project (Resource-Oriented Sanitation concepts for peri-urban areas in Africa), which aims to develop adaptable, affordable and replicable sanitation solutions in Africa, and was executed by the Arba Minch Town Water Supply, and Sewerage Enterprise (ARB), the Arba Minch University (AMU), Jupiter construction micro and small enterprise and Daylight construction micro and small enterprise.

A greywater tower was selected as one of the methods that can be adopted to treat and safely reuse greywater, in which the grey water can be used for growing vegetables successfully. The construction of the units does not require skilled labor. The aim was to raise awareness about the unit in the community of Arba Minch and promising demand has been created.

The greywater tower is a circular bag which has got soil, ash and compost mixture in it and a gravel column at the center. It is used to treat and reuse greywater, water that has been used for bathing, washing clothes and utensils. Leafy plants or vegetables are planted in holes cut in the sides of the bag itself and each day the available greywater from a household is poured directly on the gravel column. The material required to construct one greywater tower included: bucket without bottom, five poles 2m in height, 1m x 2.5m shade cloth. 0.05 m3 soil, 0.2m3 compost, 0.14 m3 ash and 0.085 m3 gravel.

The absence of sufficient finance for households interested to construct the demonstrated innovative option has constrained efforts to further scale-up implementation. The project team has recently acquired additional funding from other sources. The SPA–Programme (Sanitation Programme Africa) offers 50 % grant from the Dutch government and 50 % loan arrangements to facilitate credit access to households who would like to construct sanitation facilities including greywater. Two of the greywater towers were built for demonstration purposes. These units were considered as first testing units and the construction costs were covered fully from ROSA project budget. The other seven units were built with cost sharing whereby 75% of the total construction cost was covered by the households and the remaining 25% was covered from ROSA project budget.

The units can be operated and managed by the users. There is not any waste emission caused by the unit. The unit can serve for more than one year without any problem. After one year strengthening the unit and planting new leafy plant seedlings may be required. This can all be done by the household. The system is successfully adopted in Arba Minch town.

Bibliographic information

Shewa, W., Geleta, B. (2010). Greywater tower Arba Minch, Ethiopia - Case study of sustainable sanitation projects. Sustainable Sanitation Alliance (SuSanA)

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Case studies in SuSanA template Constructed wetlands English Greywater or wastewater Peri-urban Sub-Saharan Africa

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