Design and development of a process for acid hydrolysis of excess sludge

This research investigates a process called nitrolysis for treatment of excess sludge produced during wastewater treatment. Nitrolysis involves the treatment of excess sludge with nitric acid at elevated temperatures ( 180°C) and pressures (200 psi). This research has shown up to nearly 100% conversion of the biomass ( corrected to be free of inert materials) to products. The products include acetic acid, formic acid, and carbon dioxide. The advantage of the process is the reduction in excess sludge for disposal (reduction in cost and liability) and the production of reclaimable products. This research shows a large reduction in mass and volume of excess sludge, while producing enough acetic acid to peak an interest by industrial wastewater treatment facilities. The kinetics and stoichiometry of the process were developed and a pilot plant constructed. This aided in the development of the process on a larger continuous scale, more similar to actual wastewater treatment facilities. Six publications and numerous presentations have resulted from this work.