Reuse of wastewater for urban agriculture in Accra, Ghana

Ghana’s population has been growing rapidly since independence in 1957. This rapid growth has been accompanied by rapid urbanisation. Despite the increasing urbanisation, there has not been a national discourse on water-smart solutions for the nation nor for urban areas that face perennial water shortages.

Against this background, the EU-project WIDER UPTAKE will demonstrate the use of treated wastewater for urban farming and produce biochar from faecal sludge as replacement for wood-based charcoal. A new report presents four baseline studies conducted to prepare towards the demonstration of water-smart solutions:

• a socioeconomic study of urban vegetable farmers in the city of Accra
• a study of the quality of water presently being used by farmers
• an assessment of the wood fuel needs of selected SMEs in Accra
• a study to establish baseline characteristics of the feedstock and laboratory-produced biochar.

The studies have produced very pertinent information useful for the demonstration of the innovation solutions in the Accra Case of WIDER UPTAKE. The socioeconomic baseline findings show that the patronage of vegetables produced in the city of Accra, albeit with wastewater, is high.

Most of the farmers, who were male and aged about 40 years old, sold their produce onsite (at farm gate). The farmers did not convey their produce to market centres for sale — a sign of ready market. Furthermore, most of the farmers were solely engaged in urban farming as their main economic activity for livelihood. However, the fact that the land they cultivate does not belong to them gives cause for concern because landowners may request for custody of the land at any given time without prior information. Also, some farmers are ‘squatters’ on public land which use may change anytime there is need for such land.

The major sources of water apart from pipe-borne or dugout well were drains and streams in the city. Since most of the streams in the city are fed with water from the city’s drains, especially in the inner-city areas, it is proper to conclude that most of the stream water has been mixed with drain water carrying municipal wastewater. It is therefore gratifying to note that farmers were willing to pay for treated wastewater to be delivered to them even though they would not pay an amount that was up to the amount they presently pay for treated piped water.

The main characteristics farmers desired of treated wastewater include consistent availability, absence of bacterial/pathogen (safety), nutrients availability in the water. In view of the concern for safety and nutrient levels of water for irrigation among farmers and also the fact that there is recognition for such needs, the second baseline study presented in this report looked at the characteristics of water currently being used for urban farming at two selected sites (these are the sites that would be considered for selection in the demonstration). Also, the study looked at the characteristics of vegetables produced as well as that of the soil.

Based on FAO/WHO standards, the results of this study show that generally, the water presently being used for urban agriculture meets national standards. It is important to underscore the fact that there are no national standards but for the FAO/WHO standards. This means that as Ghana embarks on the journey for resource recovery from wastewater treatment, there would be needed to develop standards for wastewater use in the country.

It is important to note that charcoal plays a very significant role in the energy mix in Ghana, even for urban small and medium sized enterprises (SMEs), as the fourth baselines study shows. Hence, the interest of SMEs to adopt charcoal produced with alternative feedstock, such as faecal sludge is a key factor in pushing for the development of biochar that is readily available, burns well, and is safe to human and ecological health. Thus, in the delivery of sustainable energy, clean efficient burning characteristics of fuels are imperative.

The last baseline study presented in this report highlights burning characteristics of typical biomass fuels in Ghana and how it compared with biochar produced at different temperatures using faecal sludge from the Mudor Treatment Plant. Also, the elemental composition of the faecal sludge and biochar produced from the sludge is presented to serve as a guideline for the future development of a standard to produce an environmentally friendly and energy dense biochar from biomass waste.

Download the report: Baseline studies towards demonstration of water-smart solutions in Accra