Urine is very high in nitrogen (can be over 10% in a high-protein diet), low in phosphorus (1%), and moderate in potassium (2-3%). Urine typically contributes 70% of the nitrogen and more than half of the potassium found in urban wastewater flows, while making up less than 1% of the overall volume. If urine is to be separated and collected for use as a fertiliser in agriculture, then the easiest method of doing so is with sanitation systems that utilise waterless urinals, urine-diverting dry toilets (UDDTs) or urine diversion flush toilets.