Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Use of Hylocereus undatus waste for post-treatment of swine wastewater at the biodigestor efluent

¹Americas University Puebla, Dept. of Civil Engenering, Mexico
²Americas University Puebla, Dept. of Chemical Engineering, Food and Environment, Mexico
³UADY-Authonomous Univ. of Yucatan, Integration of Animal Prodcution in Tropical Agroecosystems, Mexico
⁴Dragon Fruit plantation, Mexico
⁵Research Center and Technology Assistance and Design of the Jalisco State, Mexico
⁶UADY-Authonomous Univ. of Yucatan, Dept. of Competitivity, Innovation and Technology, Mexico

Abstract

Biological treatment using biodigesters, although effective in reducing organic pollution of swine wastewater, is insufficient on its own to meet water quality standards. Therefore, complementary methods such as coagulation, adsorption, or advanced oxidation are required to remove residual contaminants. Coagulation is typically performed with inorganic coagulants based on aluminum and iron, but these have disadvantages such as high costs, environmental impact, and health risks. Therefore, this study proposes a novel line of research: the use of agricultural waste from Dragon fruit (Hylocereus undatus) stems or cuttings as a source of natural coagulant for polishing treated swine wastewater after biological treatment with biodigesters. The natural coagulant was obtained from a dragon fruit plantation by cleaning the cuttings, removing stems and thorns, cutting them into small pieces, and drying them for subsequent grinding into a fine powder. Tests were conducted using a jar tester, and analytical measurements of the variables were taken before and after treatment. The biodigester outflow was obtained from two tubular biodigeters of 4 m³ feeded with pig slurry with 45 days of hydraulic retention time. Turbidity, apparent colour, and total suspended solids removals exceeded 65%, BOD and COD removals exceeded 14%, nitrogen removals exceeded 30%, and total solids removals reached 59%, with no impact on pH (7.1). Considering the planted area in the state of Yucatán, more than 874 tons of agricultural waste could be generated annually. For each kilogram of Dragon fruit cuttings waste, an average of 122 g of coagulant could be generated, which could treat 2,000 liters of wastewater. This study evaluated the use of agricultural waste from Dragon fruit cuttings to obtain a natural coagulant for polishing pig wastewater resulting from biodigester treatment. This represents a new treatment alternative that is natural, economical, environmentally friendly, accessible, and promotes the circular economy.

Keywords: Biodigester, Dragon fruit cuttings, Hylocereus undatus, natural coagulant, pig wastewater

Contact Address: Wilbert Trejo- Lizama, UADY-Authonomous Univ. of Yucatan, Integration of Animal Prodcution in Tropical Agroecosystems, 71-A, 97246 Mérida, Mexico, e-mail: wtlizamagmail.com