Separation of faeces combined with urine diversion - function and efficiency

The main proportion of the plant nutrients in household wastewater is found in the toilet fraction, and originates from urine and faeces. Using a blackwater system, is is possible to collect these nutrient rich fractions. However, the nutrients in the blackwater are diluted by large amounts of flushwater, even if a low-flush vacuum system is used. By using a combination or urine diversion and separation of faecal matter from the flushwater, it is possible to collect the majority of the nutrients in a much more concentrated form compared to blackwater systems. The efficiency of instant separation is higher than separation in a filter bag. The efficiency of the separation depends on the system design but if correctly designed and built, it is possible to separate 84% N, 86% P and 65% K from the faecal matter. In a system where 95% of the urine is diverted and the faecal matter is instantly separated, 93% of the nitrogen, 92% of the phosphorous and 87% of the potassium are separated into a fraction comprising half the volume of blackwater from a vacuum system