Reuse and Recycling of Livestock and Municipal Wastewater in Chilean Agriculture: A Preliminary Assessment

Abstract

Chile is an agricultural power, but also one of the most vulnerable countries to climate change and water shortage. About 50% of the irrigated agriculture land in Chile is in the central zone, thanks to its agricultural-climatic characteristics that provide an adequate water supply (100-4000 m 3 /s). However, the vulnerability scenario in this zone is high due to the seasonal availability of water resources. Therefore, opportunities to use non-conventional alternative sources (e.g., wastewater) become an appealing and feasible option due to the high population and animal density (>76%) in this part of the country. Moreover, the physicochemical characteristics of the municipal and livestock wastewater suggest that there are potential opportunities to recycle nutrients for agricultural production. In Chile, wastewater reuse opportunities are noted by the wide coverage of wastewater treatment programs, with municipal and intensified livestock production taking up most of the percentage (>99%). Nevertheless, more than 70% of wastewater treatment systems reach biological secondary treatment, which suggests reuse possibilities only for non-food crops. Therefore, this paper is focused on a preliminary analysis of the potential of reusing and recycling municipal and livestock wastewater for Chilean agriculture. There is some reuse work occurring in Chile, specifically in the use of municipal and livestock wastewater for cereal crops (animal feed), forests, and grasslands. However, aspects related to the long-term effects of these practices have not yet been evaluated. Therefore, municipal and livestock wastewater in Chile could be re-valued in agriculture, but the current quality and condition of treated wastewater do not ensure its safe use in food crops. In addition, state policies are needed to provide sustainability (circular and ethic economy) to water reusing/recycling in agriculture.

Nutrients Cycle within Swine Production: Generation, Characteristics, Treatment and Revaluation

“…Thus, it is necessary to consider within slurries the balance of macro (N:P: K) and micronutrients (metals), as well as other contaminants (pathogens, emergent). Moreover, this balance must consider soil nutritional requirements and crop type, according to the international revaluation legislation [83,84]. These tools would allow the cadasters establishment, which could facilitate the communication between nutritional requirements sites (agricultural soils) and nutrients-generating sites (animal farms) [85].…”

Reuse of Treated Municipal Wastewater from Constructed Wetlands for Cut Flowers Irrigation in Aeroponic Cultivation

“…For this reason, alternative water sources are needed. Among the different sources, the reuse of treated effluents from wastewater has been explored as an alternative under these and other climatic conditions [2], [3]. However, the total percentage of treated water reused in the Atacama Desert does not exceed 10 % [4], [5], unlike other arid zones, where the percentage can exceed 70 % [6].…”

“…The low percentage of wastewater treated and reused in the Atacama Desert can be explained by several reasons. First of all, the location of the largest urban centers (Arica, Iquique, Antofagasta, La Serena-Coquimbo) on the shores of the Pacific Ocean, and the decision of the country to use submarine outfalls as a wastewater disposal system [3], [5]. A second reason is the natural geological condition that causes the salt content in soil and water to have values of 26 dS/m and 2 dS/m, respectively [2], [7].…”

Sistemas granulares aerobios para el tratamiento descentralizado de aguas servidas y su reutilización en condominios en Chile

“…Debido a los bajos costes de implantación y a su relativa sencillez de operación una alternativa para el tratamiento descentralizado de estas aguas residuales es la utilización de humedales artificiales [4], tal y como muestran experiencias realizadas en Israel [5] y Chile [6]. Estos sistemas permiten obtener un efluente con una calidad adecuada para su reutilización en agricultura [7][8]. No obstante, la elevada superficie de implantación requerida por los humedales artificiales hace que no sea factible su aplicación en condominios por lo que esta quedaría más bien relegada a zonas rurales.…”