Bentonite as an additive in the composting of wastewater sludge from the poultry agroindustry

Bentonita como aditivo na compostagem do lodo de efluentes da agroindústria avícola

Abstract

The objective of this work was to evaluate the use of bentonite as an additive in the composting of wastewater sludge from the poultry agroindustry regarding nitrogen conservation, carbon degradation, and nutrient content increase. The experimental design was completely randomized with five treatments with bentonite at 0, 0.5, 1.0, 3.0, and 6.0%, with three replicates. The organic compost used in the treatments consisted of pine sawdust and wastewater sludge from the treatment plant. During and after the composting process, the following were analyzed, respectively: pH, dry matter, temperature, and C, N, NH₄⁺, NO₂^-, and NO₃^- contents; and P, K, Ca, Mg, Cu, and Zn contents and humic and fulvic acid concentrations. Bentonite at 6.0% increased C degradation, N losses, Mg content, and humification, but decreased Zn content and humidity. Bentonite, as an additive in the composting of sludge from the poultry agroindustry, promotes humification, decreases Zn content and humidity, but does not affect pH and P, K, Cu, NH₄⁺, NO₂^-, and NO₃^- contents.

Index terms
organic fertilizer; sustainability; waste treatment