A QUANTITATIVE APPROACH TO PREDICT ... - SuSanA

Table 2:
The nutritional values of excreta before composting
Nutrient in kg/capita year
nutrient
Urine (500 l/year) Faeces (50 l/year) Total
Nitrogen (N) 4.0 0.5 4.5
Phosphorus (P) 0.4 0.2 0.6
Potassium (K) 0.9 0.3 1.2
Source: IMWI&SANDEC, 2002, p.3
During the preparation, the two forms of wastes are mixed up at a ratio of 2:1 and
dewatered on a drying bed. 165 Considering the explanation given about the different
ways of making compost, one can say that the open system approach to composting is
use in this case. The dewatered faecal sludge are then mixed up with the organic solid
wastes at the ratio of 2:1 and then composted and monitored for three months through
aerobic composting processes. This type of fertilizer produced is called co-compost.
The co-compost is then sieved and maintained at 10% moisture content. 166 Figure 5
shows the stages in making the co-compost.
165 Adamtey, Noah et al, 2009, p. 2430
166 Ibid
33