Preventing 'Phosphogeddon'?

 

Phosphates are essential components of living systems. They are integral e.g. to cell membranes, DNA structure and even the human skeleton. As there's a limited amount of phosphorus on the planet, this element has its own biogeochemical cycle (along with carbon and nitrogen). Phosphates are spread on fields to encourage the growth of plant crops. Agriculture used to get much of its needed phosphate fertiliser in the form of 'white gold'. 'White gold' was the guano (faeces) left by generations of seabirds, breeding in a number of island locations. Deposits of guano could be many metres thick. This source of phosphates is now virtually exhausted. Consequently, phosphates have to be carefully managed. Farmers tend to spread too much fertiliser on their fields (they are less efficient than in days of yore). In addition, intensive farming of animals, such as chickens and pigs, also releases phosphate-containing waste. Excess fertiliser and animal waste often end up in 'run-off', carrying their concentrated phosphates into rivers, lakes and streams. On arrival, it often causes eutrophication. Eutrophication is an explosive growth of algae, that starves freshwater organisms (like fish and invertebrates) of oxygen. The effects are often devastating. A company, Rockwell Operations (based in Wells, Somerset, UK), is currently trialling a material that can remove excess phosphates from contaminated freshwater courses. Their Phosphate Removal Material (PRM) is a sponge-like compound left in the water to absorb the phosphates. Once fully charged, PRM can be safely spread on fields, to act as agricultural fertiliser (https://www.theguardian.com/science/2025/feb/02/uk-scientist-wins-prize-for-invention-that-could-help-avert-phosphogeddon). PRM seems a useful tool in the fight to prevent 'phosphogeddon'. It, however, only potentially deals with one problem. Subsequent run-off will still enable the phosphate to make its way back into freshwater locations. Farmers need to spread their fertiliser more effectively. They also must proactively prevent animal waste from reaching rivers, lakes and streams. Chicken farms on the banks of the river Wye (between England and Wales) are a graphic illustration of this latter problem. The most wasteful human loss of phosphorus, however, occurs in human urine, discharged into our surrounding seas. Fairly obviously, this element should be extracted, in specialised sewage treatment plants, before discharge.