A strategic framework for managing wastewater – A case study of harare, Zimbabwe

Water quality is an urgent problem in Harare's main water supply source, Lake Chivero, while water scarcity will be a problem soon. This study focuses on sustainable ways of urban water and nutrient (nitrogen and phosphorus) management in Harare, part of the Lake Chivero catchment. The Dublin Principles on water conservation, environmental protection, reuse, and economic utilization of water were used as a basis for formulating innovative and responsive solutions. External and internal drivers for future evolution of wastewater approaches are identified. Water conservation, treatment, and reuse strategies are developed including water saving devices, regulation, leak detection and repair, and including wastewater treatment and reuse. The three levels where wastewater can be handled – onsite, decentralized and centralized – are discussed and solutions formulated. Based on this, a strategic framework, the so called “3-Step Strategic Approach” is then developed aimed at the sustainable use of water, nutrients, and other resources in the urban environment. This 3-Step Strategic Approach consists of pollution prevention and minimization (Step 1), reuse after treatment (Step 2), and discharge into the environment with stimulation of self-purification capacity of the receiving environment (Step 3). The 3-Step Strategic Approach was subsequently applied to the Lake Chivero catchment, which demonstrated that these strategies could substantially reduce current water pollution and future water scarcity problems in Harare.