Utilization of coal ash: Is vermitechnology a sustainable avenue?

Although various alternative energy sources have been introduced from time to time, the dependence on coal has not yet been altered significantly. Large quantities of coal ash (CA) are produced due to the combustion of pulverized coal in power plants and other industrial units. Some CAs have relatively high content of essential nutrients and water retention capacity (due to high porosity) which should add their potential for agricultural and several engineering applications. However, as hazardous components (like heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls) are preferentially entrapped in the finer proportion, a number of judicious solutions such as vermitechnology have been proposed to resolve those problems. Earthworms are demonstrated to be potent enough to treat various solid wastes. This review emphasized various aspects of hazardous contamination and beneficial role of vermitechnology for sustainable utilization of CA. Furthermore, we reviewed earthworm biology to signify its response toward soil contamination. (C) 2016 Elsevier Ltd. All rights reserved.