Investigation in Applications of Hydrolyzed Industrial Activated Sludge: Operation of Unit BX, Kingsport, TN

“Investigation of Hydrolyzed Sludge: Operation of Unit BX, Kingsport, TN” examines the treating of 15 weight percent activated sludge in a 1 ton per day pilot plant, Unit BX, with a lysing agent and heat to release the bound water contained in the activated sludge. The end-results were an assessment of the challenges for processing 15 weight percent sludge and collection of a product with water-like flow properties that is nutrient-rich suitable for the consumption by microorganisms (hydrolyzate). In addition to the development and execution of this pilot plant and examination of the functional properties of the hydrolyzate(total solids, viscosity, TOC, and BOD5), two studies were conducted with either the properties of the experimental samples or with the samples collected (from Unit BX) . These feasibility studies are recycling the hydrolyzate to a wastewater treatment (WWT) facility for reducing the hydrolyzate to carbon dioxide or slurring the hydrolyzate with coal to assess the functional properties of this mixture for potential application to a commercial gasification process.

For the evaluation of recycle of hydrolyzate to WWT, a model was developed to project the impact of recycling the hydrolyzate to WWT, Plate 1, using the property data of the hydrolyzates. Results indicate that low concentrations of lysing agent appear to be attractive; however, the presence of inerts in the WWT influent would accumulate in the recycle making this option unfeasible.

For the evaluation of slurrying hydrolyzate with coal, coal grinds with the hydrolyzate were made to compare the functional properties of a coal grind with hydrolyzate (total solids, pH, viscosity, and coal particle size distribution) with the properties of a coal grind that does not contain hydrolyzate. Findings show that at low temperature and low lysing agent or with an acidic lysing agent yield viscous and or foamy coal grinds. However, hydrolyzate samples collected at 150ºC with a basic lysing agent yielded physical properties that were comparable to a coal grind without hydrolyzate. In addition, the basic hydrolyzate showed promise as an effective agent for suspending coal particles in water compared to the standard coal grind and possible substitution with other additives.