Co-combustion of distillery sludge and coal for application in boiler and subsequent utilization of the generated bottom ash.

Combustion stands as one of the essential methods in resource recovery for disposal of distillery sludge. In this study, sludge along with coal has been considered an option for co-combustion in the grate furnace aiming for further application as a boiler fuel. Detailed analysis was carried out to verify the feasibility of co-combustion of sludge with coal. Distillery sludge was blended with coal as a mixed fuel at co-combustion ratios of 20%, 30%, and 40% in grate furnace. The results of the analysis indicated that the combustion with 40% sludge mixed coal is suitable for application as a fuel in boiler. According to the chemical composition of bottom ash, weight loss from 460 to 800°C indicated the presence of C-C and C-H. Also, EDX and XRD analyses of mixed fuel was carried out to determine the mineralogical composition. The presence of quartz (SiO2), mullite (3Al2O32SiO2), and hematite (Fe2O3) present in the ash can be used as mineral additives in cement industries. The study also provided a promising approach towards diverting combustion bottom ash from landfills for its utilization in various industries which can be a possible cost-effective solution.

A systematic review on options for sustainable treatment and resource recovery of distillery sludge.

Distillery sludge generated from the alcohol production plants is considered as a nuisance. It is one of the main sources of environmental pollution because of the presence of high amount of sulphate, phenolic compounds (500.3 ± 26.46 mg/kg), melanoidins, organic matter (14%) and heavy metals (like 18% Mn, 6% Ni and 4% Pb). Hence, advancement in the available techniques for managing this sludge is a prerequisite for its safe and sustainable disposal. The article delivers an assessment of the challenges involved in the treatment of distillery sludge, existing practices, disposal and possible routes for energy recovery. Considering the high nutritional and energy values of the distillery sludge, the associated limitations and challenges of the available sludge management options, it was aimed to highlight alternative methods of its treatment. The present review also compares the current distillery sludge management solutions concerning their environmental sustainability. The most widely used methods, including treatment and disposal techniques considering the current legislation in different countries, have also been dealt with. Furthermore, the study also deals with the resource recovery approaches in order to recover value-added products and available nutrients from distillery sludge. Resource and energy recovery options are therefore considered as sustainable solutions to fulfill the present and future energy requirement and visualize it as a potential opportunity instead of a nuisance.