From waste to resource: Cost-benefit analysis of reservoir sediment reuse for soil fertilization in a semiarid catchment

Brennda Bezerra Braga; Thayslan Renato Anchieta de Carvalho; Arlena Brosinsky; Saskia Foerster; Pedro Henrique Augusto Medeiros

doi:10.1016/j.scitotenv.2019.03.083

From waste to resource: Cost-benefit analysis of reservoir sediment reuse for soil fertilization in a semiarid catchment

Sci Total Environ. 2019 Jun 20:670:158-169. doi: 10.1016/j.scitotenv.2019.03.083. Epub 2019 Mar 16.

Authors

Brennda Bezerra Braga¹, Thayslan Renato Anchieta de Carvalho², Arlena Brosinsky³, Saskia Foerster⁴, Pedro Henrique Augusto Medeiros⁵

Affiliations

¹ Department of Agricultural Engineering, Agricultural Science Center, Federal University of Ceara, Fortaleza, CE 60.455-760, Brazil. Electronic address: brenndabraga94@gmail.com.
² Department of Agricultural Engineering, Agricultural Science Center, Federal University of Ceara, Fortaleza, CE 60.455-760, Brazil.
³ Institute of Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany; Remote Sensing Section, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
⁴ Remote Sensing Section, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany.
⁵ Federal Institute of Education, Science, and Technology of Ceará, Av. Parque Central, 1315 - Distrito Industrial I, Maracanaú, CE 61939-140, Brazil.

PMID: 30903890
DOI: 10.1016/j.scitotenv.2019.03.083

Abstract

Reservoir networks have been established worldwide to ensure water supply, but water availability is endangered quantitatively and qualitatively by sedimentation. Reuse of sediment silted in reservoirs as fertilizer has been proposed, thus transforming nutrient-enriched sediments from waste into resource. The aim of this study is to assess the potential of reusing sediment as a nutrient source for agriculture a semiarid basin in Brazil, where 1029 reservoirs were identified. Sedimentation was modelled for the entire reservoir network, accounting for 7 × 10⁵ tons y^-1 of sediment deposition. Nutrients contents in reservoir sediments was analysed and compared to nutrients contents of agricultural soils in the catchment. The potential of reusing sediment as fertilizer was assessed for maize crops (Zea mays L.) and the sediment mass required to fertilize the soil was computed considering that the crop nitrogen requirement would be fully provided by the sediment. Economic feasibility was analysed by comparing the costs of the proposed practice to those obtained if the area was fertilized by traditional means. Results showed that, where reservoirs fall dry frequently and sediments can be removed by excavation, soil fertilization with sediment presents lower costs than those observed for application of commercial chemical fertilizers. Compared to conventional fertilization, when using sediments with high nutrient content, 25% of costs could be saved, while when using sediments with low nutrient content costs are 9% higher. According to the local conditions, sediments with nitrogen content above 1.5 g kg^-1 are cost efficient as nitrogen source. However, physical and chemical analyses are recommended to define the sediment mass to be used and to identify any constraint to the application of the practice, like the high sodium adsorption ratio observed in one of the studied reservoirs, which can contribute to soil salinization.

Keywords: Agriculture; Cost-benefit analysis; Fertilizer; Reservoir sedimentation; Sediment reuse; Semiarid.

MeSH terms

Agriculture*
Brazil
Conservation of Natural Resources / methods*
Cost-Benefit Analysis*
Fertilizers*
Nitrogen*
Soil
Water Pollutants, Chemical
Water Supply

Substances

Fertilizers
Soil
Water Pollutants, Chemical
Nitrogen