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Building on an earlier feasibility study, the A-RAS-2 (A-RAS®) pilot in Nyeri County is taking Affordable Recirculating Aquaculture Systems to the next stage of scaling. The project combines water recirculation, locally produced components, solar energy and smart monitoring to develop a practical system that can increase fish production while drastically reducing freshwater use.

Facts

  • Project type PfW Pilot Project
  • Countries Kenya (Nyeri County)
  • Partners FOSPA-Africa · FOSPA-Kenya · Systemick Consultancy Limited
  • Themes Aquaculture · Water efficiency · Food security · Circular water use
  • Duration 05.12.2024 – TBC by Partners for Water
  • SDGs SDG 2 · SDG 6 · contribution to SDG 13

More fish with less water

Recurring drought and water scarcity make traditional pond-based fish farming increasingly challenging in Nyeri County. At the same time, domestic fish production falls well short of demand. According to figures supplied by the project partners, demand in Kenya was about 500,000 MT compared with domestic production of 180,000 MT in 2019.

A-RAS® builds on the first feasibility study to develop an affordable alternative that uses water, energy and nutrients more efficiently while remaining accessible to small-scale farmers. The FOSPA-Aqua-Hub, located on the border between Nyeri and Laikipia counties in Kenya’s arid and semi-arid lands (ASAL), provided the logistics for the pilot and hosted trials using three A-RAS® systems with a total of 18 fish tanks.

The pilot also considers the wider food system: local manufacturing, farmer incomes, feed, fingerlings, processing, marketing and access to nutritious food.

The objectives

The pilot aims to demonstrate an improved generation of A-RAS® under practical conditions.

The ambition is to produce up to 20 times more fish per square metre of land than conventional fish ponds, using less land (120 m² instead of 300 m²) while requiring only 2–5% of the water used by conventional ponds. Compared with existing A-RAS® systems used by farmers, the aim is to reduce water consumption to 5–10% of current levels. These are pilot targets rather than results already achieved. Current production is approximately ten times higher per square metre than in conventional ponds.

The project also aims to develop an economically viable model that can eventually be adopted by small-scale farmers across Kenya.

The approach

A-RAS® combines relatively basic, locally produced infrastructure with carefully selected higher-quality components.

The tanks are manufactured locally. A settling tank removes solid waste, which is subsequently reused as fertiliser. A nitrification tank uses microorganisms to remove nitrogen, while different oxygenation technologies – including nano- and microbubbles – are being tested. Water and air pumps are used for water recirculation and to ensure sufficient oxygenation. The system operates on solar energy.

The latest configuration being tested at the FOSPA-Aqua-Hub contains six tanks per system, with fish at different stages of growth. This will allow farmers to harvest at different times and potentially generate a more continuous income throughout the year once the configuration is adopted on farms.

A-RAS® translates high-tech into a sustainable, practical and affordable solution.

Katrine Soma
Chair and Founder, FOSPA-Africa

Farmers at the centre

Five farmers who participated in the feasibility study have also been regularly consulted during the A-RAS® pilot project. The feasibility study was conducted by FOSPA-Africa in collaboration with AquaFarmingConsult and Wageningen Social & Economic Research. Five A-RAS® installations, each consisting of four tanks, were placed on small-scale farms to identify practical opportunities and bottlenecks. The group deliberately included women, young farmers and a farmer with a disability.

While the systems showed favourable operational and production potential, the water filtration systems did not perform adequately and data collection proved difficult. The pilot therefore explored improvements to water recirculation in an environment better suited to data collection at the FOSPA-Aqua-Hub.

Feedback from small-scale farmers is incorporated throughout the development process. The project also works with the Nyeri Fish Farmers Cooperative Society, which represents around 1,000 fish farmers. This allows technical development to be continuously tested against farmers’ practical needs.

The project extends beyond the FOSPA-Aqua-Hub itself. In Kibera, local leaders, consumers and women fish vendors have also contributed ideas about fish distribution, connecting production to the wider food system.

The team

The second-phase consortium brings together three partners:

  • FOSPA-Africa: Combines research, implementation and technical and financial expertise, and develops business models to support wider adoption of the technology. Key figure: Katrine Soma, Chair and Founder of FOSPA-Africa and researcher at Wageningen Social & Economic Research.
  • FOSPA-Kenya: Represented by co-founder and Chair Charles Mbauni, who also chairs the Nyeri Fish Farmers Cooperative Society.
  • Systemick Consultancy Limited: Consortium partner. Its specific role in the pilot has yet to be confirmed.

Results and expected outcomes

  • Pilot facility: A new A-RAS® facility has been constructed at the FOSPA-Aqua-Hub in Nyeri County to collect reliable performance data and refine the technology, particularly its oxygenation systems.
  • Production capacity: Trials involved 500 fish per 7 m³ tank, equivalent to approximately 70 fish per m³. Across a footprint of 120 m², annual production was around 2,000 kg over two production cycles, compared with approximately 200 kg per cycle in a conventional 300 m² pond.
  • Water efficiency: The project aims to reduce water consumption by 95–98% compared with conventional ponds and by 90–95% compared with earlier A-RAS® systems. These are targets, not yet achieved results.
  • Scaling potential: The pilot will assess water use, fish production, system performance and affordability, providing the technical and financial evidence needed to determine whether the technology can be adopted more widely.

Looking ahead

The ambition goes beyond installing more A-RAS® units. The FOSPA-Aqua-Hub partners are developing a broader fish-food system incorporating feed, fingerlings, fish production, data collection, research, processing and training, with the intention of supporting a local network of thousands of small-scale fish farmers.

Financing models are also being developed to make the investment accessible to small-scale farmers. In the longer term, the consortium envisages expansion across Kenya and potentially into neighbouring countries such as Uganda and Ethiopia.

Why it matters

A-RAS® illustrates how water innovation can address several problems simultaneously. Recirculating water can reduce freshwater demand, intensive fish farming can increase local protein production, nutrient-rich waste can be reused in agriculture and solar energy can reduce dependence on fossil-based electricity.

But the project’s central challenge is accessibility: turning these technologies into a system that small-scale farmers can realistically finance, operate and maintain.

Innovation in Progress series

A-RAS® is presented as part of the Partners for Water Innovation in Progress series, following the transition from feasibility testing towards practical application and scaling.

The pilot applies lessons from the feasibility study to refine the technology and assess its potential for wider adoption.

 

Follow the A-RAS Journey