Exploring global nitrogen and phosphorus flows in urban wastes during the twentieth century

Abstract

[1] This paper presents a global model-based country-scale quantification of urban N and P mass flows from humans, animals, and industries and their waste N and P discharges to surface water and urban waste recycling in agriculture. Agricultural recycling was practiced commonly in early twentieth century Europe, Asia, and North America. During the twentieth century, global urban discharge to surface water increased~3.5-fold to 7.7 Tg yr -1 for N and~4.5-fold to 1.0 Tg yr -1 for P; the major part of this increase occurred between 1950 and 2000. Between 1900 and~1940, industrial N and P flows dominated global surface water N and P loadings from urban areas; since~1940, human wastes are the major source of urban nutrient discharge to both surface water and agricultural recycling. During the period 1900-2000, total global recycling of urban nutrients in agriculture increased from 0.4 to 0.6 Tg N yr -1 and from 0.07 to 0.08 Tg P yr -1. A large number of factors (the major ones related to food consumption, urban population, sewer connection, and industrial emissions) contribute to the uncertainty of À18% to +42% for N and À21% to +45% for P around the calculated surface water loading estimate for 2000.

The challenges of water, waste and climate change in cities

“…The Netherlands' drinking water sector has achieved a great deal but is faced by challenges such as salinization and groundwater depletion. There are also promising opportunities for nutrient recovery and energy conservation and production (Morée et al 2013;Frijns et al 2012). Nevertheless, water challenges require a broader framing as water is more than just drinking water (Van Oel et al 2009;Van Someren and Van Someren-Wang 2013).…”

Reactive nitrogen requirements to feed the world in 2050 and potential to mitigate nitrogen pollution

“…The resulting regional waste shares match well with current estimates 44 , but are dynamic for the future when per capita food demand rises. The Nr in sewage was estimated as the non-wasted share of food supply, not accounting for the relatively small share of Nr that is accumulated in human bodies or lost in sweat, hairs and nails 8 . Depending on the scenario assumptions, a share of sewage and organic waste is recycled to fields (RS, RW) or lost into the environment (LS, LW).…”

“…While passing through the agricultural supply chain, the Nr from these sources is subsequently lost on the field, in manure management, and as waste and sewage 1,[5][6][7][8] . As there is little long-term storage of Nr in the agricultural sector, Nr sources correspond approximately to Nr losses, and are an easily communicable indicator for the disturbance of environmental systems by Nr pollution 9,10 .…”

Nutrient fluxes from domestic wastewater: A national-scale historical perspective for the UK 1800–2010

“…Domestic wastewater is an important source of nutrients in both global and national biogeochemical cycles (Bouwman et al, 2005;Van Drecht et al, 2009;Morée et al, 2013). Indeed, it is estimated that, at the end of the 20 th century, urban wastewater contributed some 7.7 Tg/year nitrogen (N) and 1.0 Tg/year phosphorus (P) to the world's oceans (Morée et al, 2013).…”

“…Piecing together a detailed quantitative picture of historical nutrient loading from wastewater using sparse data and anecdotal evidence is a huge task. Previous studies have either focused at the detailed catchment scale (Weber et al, 2006;Behrendt et al, 2008;Gadegast et al, 2012) or provided a global assessment (Bouwman et al, 2005;Van Drecht et al, 2009;Morée et al, 2013). This paper seeks to quantify the nutrient fluxes in wastewater effluent from domestic sources in the UK for the period 1800-2010 using available evidence to develop reasonable assumptions for simulating the most important changes over time.…”