Comparative Road Dust Suppression Capacity of Molasses Stillage and Water on Gravel Road in Zimbabwe

Gravel road dust has significant health effect. The study was conducted to assess road dust suppression effect of molasses stillage in gravel at a Sugarcane Estate in Zimbabwe. Three, 2 km long gravel road sections (steep, sloping and gentle) had the following dust suppression treatments applied to 500m long segments: (i) molasses stillage, (ii) water and (iii) control. Data on dust deposition rates were subjected to Analysis of Variance (ANOVA) to compare treatment means. Mean road dust deposition rates ranged from 998.46±50.04 to 6184.02±257 mg/m2/30 days between January and June 2012. Road segments treated with molasses stillage had the lowest (P = .05) dust deposition rates compared to other treatments. Dust deposition rates were reduced by 77-83% and by 18-39% for molasses stillage and water treatments respectively. The sloping road segments had consistently the highest (P=.05) mean dust deposition rates. It was concluded that molasses stillage outperformed water as a road dust suppressant but variations were caused by type and volume of vehicular traffic together with meteorological factors at the Estate.