‘Converting the Nitrate Timebomb’ with Mike Waite, AguaDB

Mike Waite, Founder and CEO of Agua DB, spent 20 years working on improving ion exchange processes for nitrate removal in the water sector before realising that fundamentally the process was neither affordable nor sustainable – and needed a complete reboot. That time certainly wasn’t wasted – there are over 1 million people drinking water treated in plants to Mike’s process designs in the UK and US – and he learned a lot about how ion exchange really worked in the field. Mike founded Agua DB in 2017 with the primary objective of re-inventing the process – to get nutrients out of water and back onto the farm, rather than producing a waste with high disposal costs. To do that in a practical way, Mike needed to really get to grips with agriculture and start to understand how agriculture worked and the changes that the sector was going to have to go through with climate change and moving towards net zero. Mike reached out to the RAU and we’re really grateful to Prof Nicky Cannon, who became our ‘phone a(n agricultural) friend’.

We developed a concept for removing nitrate from groundwater using potash (potassium chloride), reducing nitrate levels in drinking water and converting the potash into better nutrients (potassium nitrate and potassium sulphate) and, with support from Innovate UK, we moved into a unit at Farm491 workshops, built a little pilot plant and successfully demonstrated the concept, growing a crop of baby Kale in a Vertical Farm facility at Stockbridge Technology Centre – all in a 3 month timescale! As we sat down and revisited the data after the conclusion of the project, we slowly realised that what we had could just be something significant for both the water and agriculture sectors:

  • NTPlus produces low chloride liquid nutrients, high nitrate irrigation water and low nitrate drinking water, with no waste and at 1/15th of the carbon footprint of conventional fertiliser manufacture
    • This drives local re-use in variable rate fertigation systems in irrigated agriculture and controlled environment agriculture – the products are filtered and in soft water, so obviate most maintenance issues with advanced irrigation systems
    • 20% of arable land has irrigation and produces 40% of global food – irrigation provision is forecast to almost double, driven by feeding a growing global population and as yields from rain-fed crops fall due to climate change
    • 50% of the product is potassium sulphate – which is climate change adaption for crops as, used instead of potash, it improves a crops turgor, giving a 15% yield improvement in dry years
  • Only 5% of installed irrigation is optimised. There’s a lot of work going on with integrating sensors, satellite imagery, etc., into precision irrigation control systems; NTPlus complements this and drives optimising irrigation by providing low carbon, sustainable liquid nutrients – this may just be the ‘missing link’ that kick starts the circular economy in agriculture.

Essentially, what we’re doing is to convert the ‘Nitrate Timebomb’ – all the nitrate that’s ‘gone missing’ and heading down into the aquifers – into a sustainable resource.

We also found we recovered a little bit of phosphate – that’s important as this opens up the market to nutrient recovery from waste water treatment, a circular alternative to constructed wetlands to achieve nutrient neutrality. We’re now working on recovering agriculturally significant quantities of phosphate from waste water treatment, which also will have massive benefits for both the water and agricultural sectors. It’s really interesting working at the water agriculture nexus – they’re not necessarily the best bedfellows with at least one water company CEO recently publicly blaming farmers for causing pollution, and yet the problems the water sector have need to become solutions that work for agriculture. It’s chemistry that causes pollution, and, by being a little smarter, we can use chemistry to recover these nutrients, saving costs and reducing emissions from both sectors. Watch this space!