In the Canadian province of Ontario, winter takes hold from late October to May, freezing farmland for many long months. During the period favorable for farming, the race is therefore on to grow crops as quickly as possible and maintain the rhythm of two annual harvests. The key to profitability is benefitting from fertile soil. While chemical fertilizers remain widely used, their more natural alternatives are becoming increasingly popular. This has encouraged Veolia to produce a rather special fertilizer dubbed Nutri-Pel at its Ashbridges Bay wastewater treatment plant (WWTP).
Vegetal Signals keeps track of plants
Plants can talk. They communicate with each other in various ways. For example, through mycorrhizae, which are associations between roots and fungi like neuronal networks in humans. Or by sending electrical signals, modulated according to the time of day or night, temperature or hygrometry. To better intercept this type of language, record it in real time and interpret it, the Bordeaux start-up Vegetal Signals uses techniques borrowed from neuroscience. It has also developed a system of connected sensors compiling a huge amount of data every day. To date, it has been able to identify a specific marker for water stress and develop an experimental irrigation scheme directly controlled by the plant. On the same wavelength, in 2018 SEDE Environnement became a shareholder in this budding company and has been involved in this research work since early 2019. The long-term aim is to provide decision-making tools allowing farmers to very finely tune (in terms of quantity and location) irrigation, doses of crop protection products or fertilizer intake in response to the demand coming... from the plant itself.
Rapidly visible results
The sludge from the WWTP is heated at a high temperature to be turned into pellets rich in nutrients and organic matter. “This project perfectly illustrates Veolia’s circular economy philosophy. A material seen as waste is turned into a commercially viable product that is very appealing to the end user,” notes Michael Vujicic, the project’s manager.
This view is shared by Marj Jewell, a local cattle breeder. “When we took over the farm, the soil was very poor. When we were looking for solutions to enrich it, I met the promoters of Nutri-Pel, a product that I’d never heard of. When I learned where it came from, I hesitated for a long time… But I was won over by the ecological arguments and we went for it in the end. Today, we can see the results. The land is richer and the volume of hay has significantly increased. It’s a great product and I’m delighted with it!”
The fertilizer is also well suited to pasture. “When we were using manure, the cows had to be taken out of the fields because they would flounder in the mud. We also had to deal with lots of restrictions, such as a ban on spreading it near homes. We can spread the pellets everywhere, even when there are cows!” highlights Paul Purser, Sales Manager for Nutri-Pel in Canada. The product also has the advantage of being cheaper than chemical fertilizers: it costs 25 to 35% less than the fertilizer MAP (Monoammonium phosphate), for instance, offering the same amount of nutrients. Moreover, Nutri-Pel provides additional minerals and organic matter, which nourishes the micro-organisms in soil, increases the water retention capacity, and limits erosion. Finally, the nutrients are gradually released and farmers see results in two to three years.
A key awareness-raising campaign
Today, Veolia produces and sells 25,000 metric tons of Nutri-Pel annually. However, a great deal of information provision and dialogue was required for the product to be accepted. “In 2007, when the plant started up, we were selling 5,000 metric tons per year. It was a real challenge for me as Sales and Marketing Manager,” remembers Paul Purser. “Farmers had bad memories of biosolid-based products sold well into the 1990s, whose quality was appalling.” Their main cause of concern was the presence of heavy metals. However, nowadays we know that certain natural concentrations are useful for plant development. Zinc, for instance, is used in the plant’s first stages of growth. Moreover, new standards guarantee a very low level of metals in the soil in the long term. Last but not least, controls are done twice a month in the WWTP to check compliance with standards. The quantities of 11 metals are measured, as well as nutrients such as nitrogen and calcium. Following many organized discussions about the product, farmers began to use it and then were quickly won over.
Nowadays, Nutri-Pel is so popular that Veolia is struggling to meet demand. Extremely satisfied with the scheme, the city of Toronto is currently renewing the contract with Veolia to produce pellets for the next decade.
75 orders per year
50 to 1,000 metric tons of Nutri-Pel per order
25 to 40% improvement in yield (and revenue) observed by users