Acidification of manure supplemented with carbohydrates as acid precursors

Authors: Szogi, Ariel; Shumaker, Paul; Vanotti, Matias

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2021
Publication Date: 7/12/2021
Citation: Szogi, A.A., Shumaker, P.D., Vanotti, M.B. 2021. Acidification of manure supplemented with carbohydrates as acid precursors. Meeting Abstract.

Interpretive Summary:

Technical Abstract: Acidification of manure conserves nitrogen (N), reducing ammonia (NH3) emissions from animal wastes. This approach is also practical to solubilize manure phosphorus (P) for further phosphate recovery. However, a significant barrier to the widespread adoption of acidification for animal waste is the cost of the commercial acid and the specialized equipment for handling concentrated acid. An alternative to commercial acids is the acidification of manure by adding carbohydrates as acid precursors to produce organic acids by fermentation. Our objective was to test carbohydrates to promote manure acidification as a more cost-effective alternative than commercial acids. We conducted bench experiments to evaluate the effectiveness of acidifying manure and selectively extract P using glucose, sucrose, starch, and cellulose. The tests consisted of suspensions of swine manure solids in deionized water (1:10 solid/liquid) with varying concentrations of each acid precursor (from 12.5 to 100 g/kg manure) incubated in the laboratory for up to 7 days, including one treatment control at room temperature. Significant manure acidification from pH 7.7 to about 5.5 occurred using glucose, sucrose, and starch at an application rate of 50 g/kg and five days of incubation. Simultaneously, the concentration of soluble P rose to 1500 mg/L. Food processing waste (e.g., molasses, potato starch, or fruit waste) can provide carbohydrates to reduce the cost of manure acidification treatment.