Improving land-based mariculture to meet growing demand and comply with regulations


There is evidence indicating that humans have been practising aquaculture as far back as almost 4,600BCE

Modern aquaculture systems now supply 47% of global fish supplies and it is the fastest growing food production sector in the world

The water in land-based mariculture tanks is regularly treated to convert highly toxic ammonia (a waste product from the fish) into less toxic nitrates. However, current water treatment technologies are unable to remove nitrates and other pollutants, which can then build up in the tanks. A recent update to worldwide environmental regulations requires nitrates to be removed from fish farming systems. Fish farming can take place in sea or land-based tanks.

Project Ô has developed SALTECH technology as a simple to operate and cost-effective nitrate removal process for land-based mariculture

It will treat mariculture water to create the opportunity for an almost 100% closed loop of water use by removing nitrates and other pollutants

Some of the used water can also be treated to remove some of the salt. This allows the nutrient-rich water to be used for salt-tolerant crops. These crops can be used as food for the fish.

Project Ô has developed a Circular Economy Platform (CEP) to support local water reuse

The aim is to provide a marketplace for different users involved in water treatment activities

This web application will encourage a circular water economy by providing the best matches between water demand, water flows and treatment technologies.


The National Center for Mariculture is based in Eilat, the southernmost city in Israel

NCM promote the development of mariculture as a unique branch of aquaculture

Land-based mariculture relies on the recirculation of water to remove waste. The water is filtered and treated to remove substances like ammonia which is converted to less toxic nitrates but current technology cannot remove nitrates and other pollutants, which can then build up in the tank. Environmental regulations now require nitrates to be removed.

Historically, water use has been linear, with water extracted
from one area, used and then discharged elsewhere

Project Ô has developed SALTECH technology to become part of the mariculture treatment process to remove nitrates and other pollutants. This enables an almost 100% closed loop of reused water, with the only water requiring replacement being that lost through natural evaporation. As well as meeting new environmental legislation, the system will be more efficient and cost-effective. Using CEP will provide a meeting point for various users involved in water treatment activities to circulate resources.
Developing environmentally-friendly systems for rearing fish is a key priority for NCM. While taking a circular economy approach has created the potential for additional commercial opportunities, such as providing nutrient-rich water to fertilise nearby crops.

Circular Water Economy

Using Project Ô technologies, water use in land-based mariculture can apply a circular economy approach

Project Ô technologies have helped close the loop on water use in mariculture at Eilat in Israel

And this leads to other benefits too...
  • Improving land-based mariculture allowing almost 100% closed loop of water reuse
  • Improving the local environment through a decrease in seawater extraction and decrease of used water discharged into the Red Sea
  • Commercial opportunities are possible by selling algae already grown for the denitrification treatment and by selling nutrients extracted during desalination
  • More efficient removal of nitrogen, phosphate and total suspended solids allowing for a higher recirculation rate of water and meeting tighter environmental regulations
  • Allowing land-based mariculture to move away from coastal areas relieving pressure on highly valued coastal land, bringing production closer to consumers and reducing the environmental footprint related to food transport
  • Closing the loop, requires new infrastructure and land uses which can lead to an increase in local jobs in the environmental sector 
  • Water reuse is maximised and water quality ensured through strict regulations, quality standards, management plans, permits and water policy instruments


SALTECH technology removes nitrates and other pollutants and helps recover nutrients from land-based mariculture systems

It has been designed to meet environmental regulations for good mariculture practise

Through the removal of nitrates and other pollutants, less “raw material”, in the form of additional seawater, is required. By reusing more water, a small percentage of “new” seawater is introduced to the system. The benefits of SALTECH technology include:

  • Reducing costs incurred through pumping new input water as well as taxes from discharging wastewater
  • A more stable water temperature, which can lead to an improved fish growth rate
  • Efficient management of fish disease control, which can improve yield and quality

Using SALTECH technology provides opportunity for commercial expansion

Part of SALTECH technology includes an algae-based biofilter system, which needs mass production of algae for its operation.

This creates an opportunity for commercial expansion. Algae can be used in food, as feed, for cosmetics and health, in green chemistry or as a biofuel.

Using the desalination feature of SALTECH technology could also produce a commercial product. This nutrient-rich water can be used to support the production of salt-tolerant crops in arid areas like Eilat.

CEP is designed to allow businesses to participate in a circular water economy

CEP will enable local trade of water and by-products between different water users involved in water treatment activities
It encourages the development of new business models based on a circular water economy
CEP allows key players involved in water treatment activities to interact
by sharing requests, offers, treatment technologies and logistics