Circular solution in Accra, Ghana

The challenge

At the Weija water treatment plant, Ghana Water (GWCL) produces appr. 165.000 m³/day of potable water for the greater Accra region. The treatment residual alum sludge, daily appr. 3.5 tonnes dry solids, is often discharged into their raw water reservoir. The challenge is to create an attractive alternative to the current practice of sludge disposal.

Solution and Impact

Areas of improvement of the water treatment process relate to the sludge management process, in particular to the collection and subsequent dewatering of the residual. Basically, the dewatered sludge can also be seen as a resource to create value, e.g. as a secondary raw material for the manufacturing of cement. In addition there are also non-thermal techniques to produce construction materials. Practical implementation will positively contribute to the environmental and social development of the fast-growing Accra region.

Status

Following a socio-technical feasibility study semi-industrial production of construction materials was practiced in a next phase. Allied Waters in a consortium led by Royal HaskoningDHV (NL); other partners were NETICS (NL), with support from GWCL, Safi Sana, Orange Corners and VEI (all Ghana).