The impact of diet on wastewater treatment works phosphorus loading

Abstract

Phosphorus (P) is a building block for life in which the human body requires 0.55 g of per day. In some cases, this requirement is exceeded by 2 g per day, with P additives contributing to half of this exceedance. The use of P has become prominent as demand for processed convenience foods has increased. P can cause significant eutrophication once discharged to the environment. As of October 2019, 55% of assessed rivers and 73% of assessed lakes in England failed the current water quality standards. A survey was conducted to calculate the average P consumption of individuals who identify as meat eaters, flexitarians, vegetarians and vegans based on stated eating habits and reported P levels in foods, revealing an estimated P consumption of 1715, 1664, 1244, 1125 mg P/day respectively. It was estimated that current diets contribute 45% of the P load to UK wastewater treatment works (WwTW). If the UK population were to all convert to veganism this would decrease by 54% reducing the load to WwTW by over 15,000 tonnes of P per year, or 9000 tonnes of P per year if there was a move towards a 50% vegetarian or vegan population. Finally, the population needs to be better informed on what is in their food and the associated environmental impacts.