Abstract

The proper disposal of household pharmaceutical waste (HPW) is a global challenge, particularly in arid regions with limited economic resources and inadequate sanitation infrastructure. In such contexts, composting with goat manure may offer a low-cost alternative for treating HPW, especially antibiotics like ciprofloxacin (CIP), which are linked to microorganism resistance. In this study, we evaluated whether aerobic composting with goat manure promotes the biodegradation of CIP from HPW. The experiment was conducted in 18 composting reactors over seven weeks, using two CIP concentrations (30 and 100 mg/L). Environmental conditions, physicochemical properties, and antibiotic concentration were monitored throughout. Data was analyzed using descriptive statistics, kinetics modeling, Kaplan-Meier curves, and Cox proportional hazard models with R software. The compost temperature reached 35.5 degrees C, and the final product had a pH of 8.8, electrical conductivity of 4.5 mS/cm, and a C/N ratio of 19:1. CIP exhibited a half-life of two to three weeks and followed the first-order degradation kinetics. Under high concentration conditions (100 mg/L), goat manure increased the probability of achieving >= 70% CIP degradation by the 6th week, representing a nine-fold improvement over the low concentration condition (30 mg/L). These findings suggest that aerobic composting with goat manure could be a viable and affordable strategy for reducing contamination from HPW in arid regions lacking conventional treatment options.