The WATER-MINING project aims to provide examples for real-world implementation of the Water Framework Directive to help the transition to Circular Economy. Demonstrations of innovative technologies in Cyprus, Spain, Portugal, Italy, and The Netherlands will be built to show novel efficient ways to reclaim nutrients, minerals, energy, and water from industrial and urban wastewater and seawater. The WATER-MINING project is funded with €17 million and runs from 1st September 2020 until 31st August 2024. The consortium consists of 38 public and private partners and 4 linked third parties in 12 countries across Europe and is coordinated by Delft University of Technology.
Wetsus participates in the project with our Phosphate Recovery theme. Wetsus will investigate and develop a suitable phosphorus (P) recovery method for wastewater treatment plants that use NEREDA® technology and discover synergies with Kaumera Nereda® Gum extraction. Furthermore, two technologies for phosphorus removal and recovery will be demonstrated in Cyprus and Spain on pilot-scale. Reversible P adsorption on iron-oxide adsorbents (BioPhree) and a vivianite crystallization technology called ViviCryst.
Kaumera and phosphate
Kaumera Nereda® Gum is a new bio-based raw material extracted from the sludge granules that form during the Nereda® aerobic granular sludge purification process. An essential part of the WATER-MINING project is to develop an integrated resource recovery strategy to combine phosphate recovery with Kaumera extraction for Nereda® plants. This PhD research project is carried out by Nouran Bahgat in cooperation with Delft University of Technology.
Together with partner Aquacare, Wetsus works on the development of the BioPhree-technology. With BioPhree, iron-oxide-based adsorbents remove phosphorus from water to ultra-low levels (10-50 ppb). The adsorbents can be regenerated and re-used many times, making this technology cost-effective. Recovery of phosphorus is then possible from the regeneration liquid. This technology has been demonstrated before on pilot-scale for 3 months in Canada in the context of the George Barley Water Prize. In WATER-MINING, a new BioPhree pilot will be demonstrated for two years at wastewater treatment plants in Cyprus and Spain to remove and recover phosphorus from the effluents. The extended project duration provides many research opportunities for Wetsus and Aquacare, especially regarding adsorbent regeneration.
At the case study site in Spain, our phosphate recovery technologies will follow an AnMBR demonstration plant performed by project partner Eurecat. AnMBR does not remove phosphorus. By having the phosphorus in solution at the end of the wastewater treatment process, as with AnMBR, it can selectively be removed and recovered by dosing of chemicals. This idea is not new and is called post-precipitation. Common post-precipitation technologies being used or developed today use aluminium or ferric (3+) iron to precipitate and recover phosphorus. The downside of using these chemicals is the chemical sludge that is being formed, which is difficult to dewater and process.
At Wetsus, in the WATER-MINING project, we are developing a novel technology that will precipitate phosphorus as the crystalline mineral vivianite by dosing ferrous (2+) iron under anaerobic conditions. Using a fluidized bed reactor, this technology will also produce large crystals that are easy to handle and dewater and can have a destination as iron fertilizer or raw materials for production of flame retardant and batteries. This technology is being developed at bench-scale in the Wetsus lab and will be scaled up to pilot-scale in 2022 to be demonstrated at the case study site in Spain.