Recovery of Valuable Biochemical Feedstocks from Wastewater SludgeEPA Grant Number: FP917802
Title: Recovery of Valuable Biochemical Feedstocks from Wastewater Sludge
Investigators: RedCorn, Raymond Michael
Institution: Purdue University
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2015 through August 31, 2018
Project Amount: $132,000
RFA: STAR Graduate Fellowships (2015) RFA Text | Recipients Lists
Research Category: Academic Fellowships
Waste Activated Sludge (WAS) contains a variety of industrially valuable carbohydrates. Of these possible carbohydrates, glycogen holds promise as a glucose based feedstock to produce an array of biochemicals to green industrial processes. This research will evaluate the efficacy of sonication combined with enzymatic cell disruption and alcohol precipitation, to recover glycogen from WAS.
Experiments will be performed using WAS samples from facilities performing biological phosphorous removal. Glycogen storage is a byproduct of phosphorus phosphorous removing bacteria that are treating wastewater. The WAS will be treated with an ultrasonic probe and the enzyme, lysozyme, at varying lysing times and enzyme concentrations to establish optimal methods to rupture the cells. Glycogen from the ruptured cells will solubilize in the water phase allowing other solids to be removed via centrifugation. Various alcohols at different concentrations will be evaluated for their ability to precipitate the glycogen out of solution. The purity of precipitated glycogen from WAS will be analyzed. Furthermore, a techno-economic analysis will be performed based on input costs and yields at each stage of glycogen extraction to optimize the overall process. A process which can cost effectively compete with wet milled corn starch will be the primary metric for success.
It is expected that 90% of sludge glycogen will be recoverable using this method. The ultrasonication is expected to be adequate for short contact times (<1 minutes) while the time needed for enzyme lysing is expected to be greater than 1 hour. The ability to immobilize lysozyme and reclaim alcohol in the process is expected to be critical to economic viability.