Work

Is urine concentration by reverse osmosis economically viable for its reuse as fertiliser?

Year: 2025

Type: article

Abstract: The demand for fertilisers is growing, and increased fertiliser production has significant environmental impacts. Human urine, rich in nitrogen, phosphorus, and potassium, presents a sustainable alternative; however, the long-distance distribution from urban to rural areas poses challenges for commercial operations. Researchers suggest concentrating urine using reverse osmosis (RO) to reduce distribution cost, but its economic feasibility remains uncertain. A techno-economic assessment was conducted based on demographic and geographic data of Greater Melbourne area to assess the feasibility of RO hydrolysed urine concentration under different distribution modes (decentralised and centralised), with volume reduction factors (VRF) of 2.0 and 3.0, across distribution distances ranging from 0 km to 550 km. With a 7% discounted cash flow rate, unconcentrated urine is the most cost-effective option at distances less than 248 km. Beyond 248 km, urine concentrated to a VRF of 2.0, with decentralised RO becoming the most cost-effective option, with the minimum selling price of A$8.19/kgN. Centralised RO requires a feasible distribution distance of more than 320 km. Concentrating urine to a VRF of 3.0 does not reduce the distribution distance needed for RO concentration to be economically viable. A 248 km radius typically covers the entire city centre and peri-urban areas. Therefore, the viability of adopting RO for urine concentration depends on the customer acceptance of the fertiliser selling price, the proportion of customers located beyond 248 km, and the availability of surplus urine to meet demand beyond this range. • Viability of urine concentration using RO to reduce distribution cost was assessed. • Unconcentrated urine is the viable option for distribution distances below 248 km. • Decentralised RO concentration becomes viable beyond 248 km at A$8.19/kgN. • Centralised RO only becomes viable when distribution exceeds 320 km. • Broadacre agricultural businesses are the primary beneficiaries of RO concentration.

Source: Journal of environmental chemical engineering

DOI: 10.1016/j.jece.2025.120139