Suitability and economic viability of bioremediated hydrocarbon-contaminated drill mud waste for cultivation of selected food crops

Abstract

Bioremediation can condition contaminated soil for agricultural production, although this potential has scarcely been explored in many developing countries. In this study, the suitability and economic viability of a bioremediated hydrocarbon-contaminated drill mud waste (HCDW) for production of tomatoes ( Solanum lycopersicum L.), cowpea ( Vigna unguiculata (L.) Walp) and okra ( Abelmoschus esculentus (L.) Moench) were evaluated using a pot experiment. The experimental treatments comprised 36 pots filled with the bioremediated soil (2 kg substrate each) and 12 pots with agricultural soil (topsoil) as control. The pots were planted with the three food crops in equal proportions and laid out in a completely randomized design. Physicochemical quality indicators of the HCDW (pH, texture and total nitrogen) as well as growth and yield performance indicators (plant height and fresh weight of pods or fruits) were determined through standard procedures. Results showed that the bioremediated HCDW was suitable for crop production as suggested by the greater growth performance (mean height = 39.6 cm, mean number of fruits per plant = 11; mean fresh weight = 45.5 g) in tomatoes compared to the control soil (height = 36.1 cm; number of fruits per plant = 12; fresh weight = 39.6 g). On the contrary, the cowpea and okra recorded lower growth and yield performances relative to the control, likely due to the high clay content and moderately basic pH of the bioremediated HCDW. A positive gross margin of $4914.14 and a benefit–cost ratio of 1.38 amply demonstrate the economic viability of using the remediated soil for tomatoes cultivation. Overall, findings from this study demonstrate the potential for the reuse of bioremediated HCDW for vegetable production, which can be explored for large-scale application. • The bioremediated hydrocarbon contaminated drill mud waste (HCDW) was characterized. • Soil quality of the treated HCDW was enhanced by the organic soil additives. • The suitability of the bioremediated HCDW for tomatoes production was revealed. • Economics analysis revealed that using the bioremediated hydrocarbon contaminated for tomatoes production was profitable.