TY - JOUR

T1 - Plant-based diets add to the wastewater phosphorus burden

AU - Forber, Kirsty

AU - Rothwell, Shane

AU - Metson, Genevieve

AU - Jarvie, Helen

AU - Withers, Paul

PY - 2020/8/19

Y1 - 2020/8/19

N2 - Global food production and current reliance on meat-based diets requires a large share of natural resource use and causes widespread environmental pollution including phosphorus (P). Transitions to less animal-intensive diets address a suite of sustainability goals, but their impact on society's wastewater P burden is unclear. Using the UK as our example, we explored historical diet changes between 1942 and 2016, and how shifting towards plant-based diets might impact the P burden entering wastewater treatment works (WWTW), and subsequent effluent P discharge to receiving water bodies. Average daily per capita P intake declined from its peak in 1963 (1599 mg P pp-1 d-1) to 1354 mg P pp-1 d-1 in 2016. Since 1942, the contribution of processed foods to total P consumption has increased from 21% to 52% in 2016, but consumption of total animal products has not changed significantly. Scenario analysis indicated that if individuals adopted a vegan diet or a low-meat ('EAT- Lancet') diet by 2050, the P burden entering WWTW increased by 17% and 35%, respectively relative to baseline conditions in 2050. A much lower P burden increase (6%) was obtained with a flexitarian diet. An increasing burden of P to WWTW threatens greater non-compliance with regulatory targets for P discharge to water, but also presents an opportunity to the wastewater industry to recycle P in the food chain, and reduce reliance on finite phosphate rock resources. Sustainable diets that reduce food system P demand pre-consumption could also provide a source of renewable fertilizers through enhanced P recovery post-consumption and should be further explored.

AB - Global food production and current reliance on meat-based diets requires a large share of natural resource use and causes widespread environmental pollution including phosphorus (P). Transitions to less animal-intensive diets address a suite of sustainability goals, but their impact on society's wastewater P burden is unclear. Using the UK as our example, we explored historical diet changes between 1942 and 2016, and how shifting towards plant-based diets might impact the P burden entering wastewater treatment works (WWTW), and subsequent effluent P discharge to receiving water bodies. Average daily per capita P intake declined from its peak in 1963 (1599 mg P pp-1 d-1) to 1354 mg P pp-1 d-1 in 2016. Since 1942, the contribution of processed foods to total P consumption has increased from 21% to 52% in 2016, but consumption of total animal products has not changed significantly. Scenario analysis indicated that if individuals adopted a vegan diet or a low-meat ('EAT- Lancet') diet by 2050, the P burden entering WWTW increased by 17% and 35%, respectively relative to baseline conditions in 2050. A much lower P burden increase (6%) was obtained with a flexitarian diet. An increasing burden of P to WWTW threatens greater non-compliance with regulatory targets for P discharge to water, but also presents an opportunity to the wastewater industry to recycle P in the food chain, and reduce reliance on finite phosphate rock resources. Sustainable diets that reduce food system P demand pre-consumption could also provide a source of renewable fertilizers through enhanced P recovery post-consumption and should be further explored.

U2 - 10.1088/1748-9326/ab9271

DO - 10.1088/1748-9326/ab9271

M3 - Journal article

VL - 15

JO - Environmental Research Letters

JF - Environmental Research Letters

SN - 1748-9326

IS - 9

M1 - 094018

ER -