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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Phosphorus
• diet
• source apportionment
• wastewater
• veganism

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Letter to the editors of environmental technology

Acknowledgements

The authors wish to thank the co-ordinator of the CIP programme – UK Water Industry Research (UKWIR) for providing the information reported here, and the UK Water Utility companies Anglian, Dwr Cymru, Northumbrian, Scottish, Severn Trent, Southern, South West, Thames, United Utilities, Wessex and Yorkshire Water for their considerable efforts in generating it. The authors would also like to thank Mr Daniel Comber for his invaluable advice regarding diets and protein consumption information.

Disclosure statement

No potential conflict of interest was reported by the author(s).