Potential for nutrients reuse, carbon sequestration, and CO2 emissions reduction in the practice of domestic and industrial wastewater recycling into agricultural soils: A review

This review assesses the feasibility of reusing treated wastewater for irrigation in agricultural soils as a strategy for nutrients recycling and mitigation of CO2 emissions. Through a literature review, it was examined wastewater sources enriched with carbon and nutrients, including municipal wastewater and associated sludge, vinasse, swine wastewater, as well as wastewater from the food industry and paper and pulp production. The review also explores the dynamics of organic matter within the soil, discussing the aspects related to its potential conversion to CO2 or long-term storage. It was found that industrial wastewaters, owing to their higher organic matter and recalcitrance, exhibit greater potential for carbon storage. However, the presence of pollutants in wastewater necessitates careful consideration, particularly concerning their impact on soil quality. Toxic metals, microplastics, and organic compounds emerged as significant contaminants that could accumulate in the soil, posing risks to ecosystem health. To mitigate the environmental impacts, it was evaluated various wastewater treatment technologies and their associated carbon emissions. While advanced treatments may effectively reduce the contaminant load and mitigate soil impacts, their adoption is often associated with an increase in CO2 emissions. Membrane bioreactors, microfiltration, ultrafiltration, and up-flow anaerobic sludge blanket reactors were identified as promising technologies with lower carbon footprints. Looking ahead, future research should aim to enhance the understanding of carbon dynamics in soil and validate the environmental impacts of treated wastewater disposal. Despite remaining uncertainties, the literature indicates a positive outlook for wastewater recycling in soil, offering a viable strategy for carbon storage and mitigation of greenhouse gas emissions. [Display omitted] •The carbon dynamics within soil systems remain poorly understood.•Industrial wastewaters contain higher concentrations of carbon suitable for storage within soil.•Antibiotic resistance genes pose minimal concern due to their short lifespan within soil.•Trace metals and microplastics from wastewaters have the potential to accumulate over time.