Synergies in the Co-Valorization of Sugar and Agroindustrial Byproducts: Physicochemical Screening and Exploratory Classification of Filter Mud-Based Amendments

Abstract

The transition from conventional agro-industrial production toward circular bioeconomy models requires the comprehensive valorization of process by-products as resources (“Waste-to-Wealth”). This study presents an exploratory physicochemical characterization of four biotechnological pathways—composting, vermicomposting, accelerated Bokashi-type fermentation, and biol production—for transforming filter mud (cachaza), sugarcane trash, boiler ash, bagasse, vinasse, and other agro-industrial by-products into candidate soil amendment formulations. Based on analytical procedures established by official Mexican standards (NOM), pH, electrical conductivity (EC), organic matter (OM), macronutrients (N–P–K), and the carbon-to-nitrogen ratio (C/N) were characterized across 37 distinct, non-replicated formulations, revealing pronounced physicochemical heterogeneity and three preliminary functional profiles. Vermicompost-derived formulations exhibited relatively high OM and nutrient contents and C/N ratios within a range commonly associated with stabilized organic materials. In contrast, alkaline Bokashi formulations incorporating ash and agricultural lime produced highly alkaline matrices (pH > 10) with high calcium concentrations (up to 37% CaO), suggesting potential for use as acidity-correcting mineral–organic amendments. The liquid BIOL formulation exhibited a high K2O concentration (27.35%), identifying it as a candidate potassium-rich liquid formulation; however, its suitability for fertigation or foliar application requires appropriate dilution, salinity and phytotoxicity assessment, and controlled agronomic validation. Exploratory multivariate screening differentiated the 37 formulations into distinct physicochemical profiles, indicating that filter mud-based amendments do not constitute a chemically uniform product class but rather encompass formulations with contrasting compositional characteristics and potential functional niches. These findings support a differentiated cascade-valorization framework for sugarcane agro-industrial by-products, while agronomic performance, phytotoxicity, sanitary safety, environmental impacts, economic feasibility, and reproducibility across production batches require independent validation before field-scale or commercial application.