Author(s)

Boqi Weng, Junli Zhou, Siping Zheng, Xiuxia Chen, Weiguang Zhang, Qin Huang

Agricultural Ecology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China.
Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China.
School of Chemical Engineering, Tianjin University, Tianjin, China.

This research demonstrated the feasibility of converting source-separated human urine into a solid fertilizer by means of continuous absorption and solar thermal evaporation using dried water hyacinth as adsorbent. In a preliminary experiment, the dried petioles of water hyacinth (DWH) absorbed urine in a mean rate of 18.78 ml·g^-1 within 7 d, retrieving about 3.46% urine dissolved solids (UDS). In an advanced experiment, the DWH’s capacity of urine absorption declined from an initial 2.73 L·kg^-1·d^-1 to 0.68 L·kg^-1·d^-1, with a requirement of material change in about 25 effective days and an average ratio of 25 (L) to 1 (kg). Phosphorus (P₂O₅) concentration in the adsorbent increased from 0.46% (material baseline) to 3.14% (end product), suggesting a satisfactory recovery of the element. In field application, the urine was discharged, not in wet weather, onto the DWH via a tube connected to a waterless urinal. There are several ways to use the UDS-DWH as P(K)-rich fertilizer, e.g., making soluble fertilizer for foliage spraying to encourage prolific flowering and fruiting. Apparently, utilization of water hyacinth waste to recover dissolved plant nutrient elements from source-separated urine will benefit the environment in a wide range of perspectives. The herein innovative use of water hyacinth is also expected to be useful in the recycling of certain dissolved hazardous materials.

Dried Water Hyacinth; Urine Dissolved Solids; Phosphorus Recovery; Waste Utilization; Source-Separated Human Urine

B. Weng, J. Zhou, S. Zheng, X. Chen, W. Zhang and Q. Huang, "Field Utilization of Dried Water Hyacinth for Phosphorous Recovery from Source-Separated Human Urine," Journal of Environmental Protection, Vol. 3 No. 8, 2012, pp. 715-721. doi: 10.4236/jep.2012.38085.