Background

A major impact of climate change in SSA countries is on the water resources. Adoption of effective adaptation technologies in the water sector is essential to ensure resilience of the water resources systems and a better protection of cities against floods. 

ALGAE: Nutrient Harvesting for Improved Wastewater Effluent Quality “A low cost, green solution for wastewater treatment”

Overview

Research Partners: The Council of Scientific and Industrial Research (CSIR) (South Africa), together with the University of Malawi and the University of Botswana

A low-cost green technology exists that has proven to achieve greater treatment efficacy with established wastewater treatment infrastructure.

Waste stabilisation pond systems are still being used in most rural communities and towns and are ideally suited for sewage treatment because they are simple and economical to operate and maintain. The algae-based treatment process uses a specific consortium of algal species to remove nutrients and create conditions for effective solar disinfection to reduce pathogens in such pond systems. The self-sustaining system operates independent of electricity or expensive chemicals and can be effectively managed within financial and capacity constraints.

Governance and technical constraints often hamper or prevent successful implementation of people’s constitutional rights and provisions. This approach provides a technical solution for improved wastewater effluent quality, combined with governance guidance and ownership; thereby supporting effective policy implementation.

Key Findings

  • The sustainable design and operation of a waste water treatment plant is inextricably linked to its environmental and economical footprint. High treatment efficiency and low energy consumption are key to sustainability. The current study showed that the proposed algae technology is low cost and environmentally friendly and can easily be sustained.
  • There was significant reduction of total phosphorus, nitrogen and chemical oxygen demand in the unfiltered water of the tested waste water treatment plant after algae treatment. Total nitrogen and phosphorus varied from one pond to another before treatment, but decreased along the treatment system after the algae treatment.
  • This consortium of specific algae were selected on the basis of robustness, maximum nutrient absorption, survival in different temperature ranges and effectively inhibit coliforms and pathogens. Other algae and conventional treatment technologies currently on the market require high cost investment, electricity for mixing of algae, need skilled labours to maintain the system, and do not use a specific consortium of algae for maximum absorption. Conventional waste water treatment plants use non-environmentally friendly chemicals and depend on mechanical mixing, which requires constant electricity supply.
  • Treatment technology can serve as adaptation measure for climate change at WWTW in rural areas under different climate conditions.
  • This approach brings significant opportunities for municipalities to address the backlogs in wastewater treatment, since it uses existing infrastructure with a more effective treatment process to address the risks of untreated to partially treated wastewater. 

Economic assessment of large power photovoltaic irrigation systems in the ECOWAS region

Overview

Research Partners: ECOWAS Centre for Renewable Energy and Energy Efficiency (ECREEE), in collaboration with the Solar Energy Institute of the Universidad Politécnica de Madrid (IES-UPM).

Irrigation for agricultural applications is a very high water and electricity-consuming activity, as most of the water demanded must be pumped from underground reservoirs. Traditionally, water pumps are powered by the local electric grid, if accessible, or by diesel generators in isolated regions or in regions where the grid service is unreliable. In any case, diesel or electricity consumption represents a significant share of the economic cost required in any agricultural plantation. 

This paper presents an economic assessment of large power (from tens to hundreds kWp) PV irrigation systems in the ECOWAS region, evaluating the economic feasibility of substituting diesel-powered and grid-powered systems with PV ones. Seven countries from the ECOWAS region were considered and two irrigation operating modes were compared (pumping to a water tank or at constant pressure).

Key Findings

  • Net present cost values are all positive and in the range $33,000 - $4,150,000
  • Net present costs present a linear correlation with diesel prices and electricity prices.
  • Internal rate of return values are all higher than the local real discount rate and in the 8 - 47% range. 
  • Internal rate of return presents a linear correlation with diesel prices and electricity prices.
  • Payback periods are far below the lifetime of the systems (25 years), in the 2.1 - 10 years range. The payback period presents an exponential correlation with diesel prices and electricity prices.
  • Levelized Cost of Energy values are the lowest for PV irrigation systems and in the 4.5 - 17.4 $cents/kWh range, representing very high percentage savings in the range 30 - 84% if compared to diesel-powered and grid-powered systems.
  • In general terms, substituting diesel-powered and grid-powered systems with PV irrigation systems in the region of ECOWAS seems very promising from the economic point of view. Profitabilities are higher when the irrigation system is pumping to a water tank than at constant working pressure, and they present little sensitiveness to variations in DP or EP and to the size of the system.

AWAKE: African Water Adaptation through Knowledge Empowerment

Overview

Research partners: ICLEI - Local Governments for Sustainability - Africa Secretariat (ICLEI Africa), together with the Climate Systems Analysis Group of the University of Cape Town (UCT).

This explorative qualitative study utilised the IPCC categories of adaptation opportunities and constraints as a framework to understand the barriers and enablers to the development and uptake of contextually relevant climateresilient water management technology in three sub-Saharan African cities. In-depth interviews were undertaken with interviewees from the research, government and civil society sectors to gain insight into perceived opportunities and constraints to the development, uptake and market dissemination of such technology in Blantyre, Harare and Gaborone. Results indicated that the nuances of the Global South context are often not well-considered in the design of climate-resilient water management technology, and that a number of constraints detract from the development, uptake and dissemination thereof. There are however opportunities inherent to sub-Saharan African cities which could be capitalised on to stimulate the development, uptake and dissemination of locally designed or modified water technology. New frontiers for exploration of this topic are discussed by way of conclusion.

Key Findings

  • Knowledge, awareness and technology constraints are significant barriers to the development and uptake of climate-resilient water management technology.
  • It is proposed that the following three steps are important in overcoming constraints to the development and uptake of climate-resilient water technology:(1) Up-skilling, encouraging behaviour change and capacitating all sectors of society to engage in the climate change and water management space, which links to awareness raising, capacity building and tools opportunities; (2) once this capacitation has occurred, mechanisms need to be in place where innovative ideas (linked to innovation opportunities) can be brought, developed and tested, in a safe and trusted environment; and (3) that the economic and financial environment is such, that these ideas can be taken to scale. 

The design and development of technology to harvest, treat, and supply water should first and foremost consider the context within which its intended recipients are situated.

Opportunities exist in southern African countries for:

  • Off-grid or renewable energy powered technology options.
  • Development of partnerships that allow for community involvement in technology development to ensure uptake and acceptance.
  • Economic or financial incentives for small-scale entrepreneurs to develop home-grown technology, which has the potential to increase technology uptake, dissemination and local economic development.
  • Non-electrified or manual technologies to supply and treat water.
  • Wastewater reuse.
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