The use of source separated human urine as fertilizer is one of the major suggestions of the new sanitation concept ECOSAN. Urine is rich in nitrogen, phosphorus and potassium which act as plant nutrients, however its salinity is high for agricultural and landscape purposes. Moreover, characteristics change significantly throughout storage where salinity increases to higher values as the predominant form of nitrogen shifts from urea to ammonium. Transferring nitrogen in human urine onto the natural zeolite clinoptilolite and using the subsequently recovered ammonium from the exhausted clinoptilolite for agricultural/landscape purposes is suggested as an indirect route of using urine in this work. Results reporting the outcome of the proposed process together with characterization of fresh and stored urine, and preliminary work on the application of the product on the landscape plant Ficus elastica are presented. Up to 97% of the ammonium in stored urine could be transferred onto clinoptilolite through ion exchange and about 88% could be recovered subsequently from exhausted clinoptilolite, giving an overall recovery of 86%. Another important merit of the suggested process was the successful elimination of salinity. Preliminary experiments with Ficus elastica had shown that the product, i.e. clinoptilolite exhausted with ammonium, was compatible with the synthetic fertilizer tested.

Source-separated human urine may be used as a source of fertilizers indirectly through processing with clinoptilolite. The suggested form of fertilizer is clinoptilolite loaded with plant nutrients from urine, where nitrogen and phosphorus will be released upon contact with water. Triggered by the need for handling high concentrations remaining in the liquid phase to be disposed of, this paper aims to present the option of improving the residual nutrient quality through stagewise processing with clinoptilolite, while investigating any improvement in nutrient removal. Two sets of experiments, stagewise operation under (i) constant loadings and (ii) variable loadings in each stage, are discussed. Stagewise operation has been observed to be successful for attaining reduced residual liquid phase concentrations as well as improvements in nitrogen recovery as compared to single-stage operation. Comparing constant and variable stagewise loadings, the final concentration is 10 times lower with variable loadings. The latter is comparable to a level found in only 1% of conventional domestic wastewater volume. Stagewise operation was beneficial from the standpoint of both additional nutrient recovery and for residuals control, with more pronounced benefits for attaining higher quality residual liquid phase concentrations to be disposed of.

Yellow water is a segregated domestic wastewater stream resulting from Ecological Sanitation (ECOSAN). It is mainly source separated human urine which is rich in nutrients. The potential contribution of yellow water as fertilizer to food security is considerable. The use of this potential however is related to the acceptance of the consumers towards urine based fertilizers (UBF). This work aims to assess acceptance of consumers towards UBF and urine diverting toilets (UDT) for separation of urine, through questionnaires with 444 participants from Egypt, Iraq and Turkey with different age groups, genders, educational backgrounds and occupations. The overall acceptance for UDTs and UBF was 62% and 56%, respectively. All-in-all, public opinion regarding the use of UDT/UBF is promising.