Wastewater - Turning Problem to Solution

Globally, there is still a low rate of replacement of industrial fertilizer with wastewater derived nutrients. Whilst Kok et al. (2018) calculated that at its maximum potential, 20 per cent of global phosphorus demand for agriculture (approximately 19.1 million tonnes/year)

could be met from the recovery of phosphorus from urban wastewater alone. However, because of continued but limited availability of cheap rock phosphate in the market only 0.8 per cent of the agricultural demand is actually currently economically feasible (calculated for 2015).

Phosphorus and nitrogen use replaced by urine

Phosphorus and nitrogen use replaced by urine

Less than 25% More than 75% >25% to <75 %

Less than 25% More than 75% >25% to <75 % Phosphorus and nitrogen use replaced by urine

No data

No data Less than 25% More than 75% >25% to <75 %

No data

Figure 2.11 (continued)

Source: adapted from Simha 2021; GRID-Arendal/Studio Atlantis, 2023.

Source: adapted from Simha 2021; GRID-Arendal/Studio Atlantis, 2023.

Table 2.1: Composition of different fractions of household wastewater produced per person and year.

Source: adapted from Simha 2021; GRID-Arendal/Studio Atlantis, 2023.

Unit

Urine

Faeces

Grey water

Kilogram (kg) kg Gram (g) g g g g Milligram (mg)

550 21

51 11

36 500 20 9 500 19 000

Wet mass Dry mass Biological oxygen demand, 7 days Chemical oxygen demand Nitrogen Phosphorus Potassium Copper Chromium Nickel Zinc Lead Cadmium Mercury

– – 4 000 365 1 000 37

– –

550 183 365 400 7.3 27 3 900

500 190 365 2 500 365 450 3 650 350 12 1.5

mg mg mg mg mg mg

3.7 2.6

16.4 0.73 0.25 0.3

7.3 3.7 3

Source: Vinnerås et al. 2006.

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