Work

Cost-effective urban farming with alternative water sources treated by nature-based solutions: A critical review of global practices

Year: 2026

Type: article

Abstract: Urban agriculture supports food security and circular resource use in cities, yet expansion is hindered by limited clean irrigation water. This review examines five alternative water sources available in urban environments (i.e., greywater, blackwater, groundwater, rainwater, and stormwater) for urban crop irrigation, assessing their agronomic suitability and contaminant profiles through systematic global literature synthesis. Four nature-based solution (NBS) technologies (i.e., constructed wetlands, biofilters, green roofs, and green walls) were evaluated as pre-treatment systems, alongside international regulatory frameworks and an economic model applied to tomatoes, faba beans, and sweet peppers. Each water source presents a distinct risk-benefit profile, with contaminants spanning nutrients, pathogens, heavy metals, and emerging pollutants. NBS technologies effectively reduce these risks while retaining crop-beneficial nutrients, with hybrid systems such as wetland-biofilter combinations achieved removal efficiencies exceeding 97% for TSS, BOD, and COD. Crop selection was decisive for economic viability, with high-value crops such as tomatoes and sweet peppers irrigated with treated groundwater yielded the greatest profitability, while faba beans remained unviable regardless of treatment approach. Policy analysis identified substantial governance gaps, including inconsistent enforcement, limited public acceptance, and minimal regulatory guidance specific to urban agricultural water reuse. By integrating treatment technology, crop suitability, economic viability, and policy considerations into a unified framework, this review demonstrates that alternative water sources can meaningfully advance food security and support multiple Sustainable Development Goals when appropriate safeguards are in place.

Source: Agricultural Systems

DOI: 10.1016/j.agsy.2026.104881

Authors: Niloofar Shoja Razavi, Kefeng Zhang, Veljko Prodanovic

Institutions: University of California, Riverside, UNSW Sydney, Istraživačko-razvojni institut za veštačku inteligenciju Srbije

Language: English

Topic: Wastewater Treatment and Reuse

Subfield: Waste Management and Disposal

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Zero hunger, Sustainable cities and communities, Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $4,000