Enhancing management of and value from phosphate resources

The essential crop and animal nutrient phosphorus is vulnerable to unnecessary depletion by poor management practices in the production/consumption life-cycle and by failure to recover phosphorus from city and other waste streams. There are concomitant opportunities to extract, conserve and continuously recycle available phosphate and its co-products more effectively. In the ‘wet process’ method of manufacturing phosphate fertilisers, two resources are typically ignored: uranium in the phosphoric acid, and the phosphogypsum residue. Uranium used as a nuclear fuel source may free land for growing food rather than fuel crops; using phosphogypsum as a soil amendment can increase the productive capacity of the world’s available soils; phosphogypsum is a cost-effective substitute for virgin construction materials, such as roads or housing. Adopting an integrated, system-wide approach to managing phosphate resources and co-products is a necessary consequence of applying policies of sustainability and resource conservation. The contribution that creative civil engineering can make towards achieving this goal is pivotal.