UTILIZATION OF INDUSTRIAL SOLID WASTES FOR ENVIRONMENTAL APPLICATIONS AND RECOVERY OF VALUABLES

Abstract

The generation of industrial solid waste has increased exponentially with an increase in population, industrialization, and human activities. Technological advancements also add a considerable quantity and variety of potentially hazardous materials to the waste. Industries like sugar, textile, distilleries, chemicals, steel and ore processing, electroplating, mechanical manufacturing, coal power plants, paper, fertilizer, and tanneries are heavily polluted. These industries inevitably generate an enormous quantity of liquid and solid waste (sludge). The treatment of industrial wastewater has been well documented through numerous physicochemical methods. Although, there is a scarcity of literature associated with industrial sludge management, disposal, and resource recovery. Furthermore, the sulfur-rich sludges generated from process industries are also challenging to manage due to their hazardous potential towards the environment. Industries such as sulfuric acid plants, zinc ore industry, natural gas and heavy oil processing, petroleum refining, acid waste from gold and coal mines, maize processing generate a massive quantity of sulfur-rich solid waste. Conventional techniques for industrial waste disposal are landfills, incineration, road surfacing, forest renovation, sea dumping, and conversion into building blocks. These practices have major environmental issues like soil and water contamination due to the leaching of harmful chemicals, releasing toxic gases and other harmful pollutants into the atmosphere. In contrast, sulfur-rich sludge (SRS) comes under the class of hazardous waste that is ultimately handled by the treatment, storage, and disposal facilities (TSDFs). They are dumped in isolated landfills that involve a substantial economic burden on the industries. The frequency of studies reported such sludges are significantly less due to several challenges and lack of appropriate and efficient management technology The transformation of industrial sludge into sustainable, efficient, and low-cost activated carbon/biochar by physical or chemical activation is the most suitable approach to manage such wastes. Further, this biochar could be used for various environmental applications like adsorbent, catalyst preparation, and precursor material for electrode preparation of energy-storage devices. In contrast, the application of sludge-based biochar for the remediation of persistent pharmaceutical pollutants has gained researchers' attention. This approach simultaneously handles two environmental problems: first, the management of industrial solid waste, and second, the removal of contaminants from wastewater.