Date of Award
Master of Science
Agricultural and Biosystems Engineering
Jacek A. Koziel
Animal waste is considered to be a significant source of potentially hazardous and odorous emissions. Emissions associated with swine manure consist of gases such as ammonia (NH3), hydrogen sulfide (H2S), greenhouse gases (GHGs) and volatile organic compounds (VOCs). Comprehensive, effective, practical, and inexpensive treatment is in high demand. Biochar is mainly known for being soil amendment, has been used for remediation of heavy metals from wastewater, and as an adsorbent for gases due to its porosity. Thus, it is proposed that biochar could be used as an effective and practical treatment for gaseous emissions from stored manure. Data is needed on the performance of biochar to mitigate gaseous emissions from swine manure including simple floatation tests. The hypothesis of mechanism how biochar mitigates emissions from swine manure is that it can influence manure pH, and by that inhibit gaseous emissions transfer from liquid to air, by, for instance, preventing NH4+ transformation to gaseous NH3. Two types of biochars, highly alkaline and porous (HAP) biochar made of corn stover with pH=9.2 and red oak (RO) biochar with pH=7.5, were tested. The first experiment was designed to identify if HAP and RO biochars would be able to change spatial (every 1 mm of depth) and temporal pH of tap water (pH=9.2) and deionized water (pH=5.4), while floating on the surface. The study showed that biochars immediately changed the pH of deionized water on day 0, which had lower buffer capacity while the pH of tap water was significantly changed only on day 2. A separate experiment was performed to visualize tap and deionized water pH change because of influence of biochar floating on the water surface by using colorimetric pH indicator and corn starch to densify the solution and prevent biochars from sinking, which supported the results of the first experiment.
The second experiment was a study of how topically applied biochar influenced pH of the outdoor-stored (pH=7.55) and pit manure (pH=8). The experiment showed that biochar altered outdoor-stored manure pH while pit manure had no significant change in pH. The reason for that was lower buffer capacity of outdoor-stored manure in comparison with pit manure.
Finally, the effect of both type of biochars on odorous compounds emitted from swine manure was tested on a laboratory scale. The study consisted of three 30-day trials, where biochars were applied on top of the manure and emissions of NH3, H2S, GHGs, and VOCs were measured and compared. Treatments showed the highest reduction of NH3 on the first days of all trials and a gradual decrease in the mitigation effect with the time. Emissions of methane decreased for the first two weeks of trials, then increased. The reduction of phenolic compound emissions was observed.
Meiirkhanuly, Zhanibek, "Evaluation of biochar for mitigation of ammonia, hydrogen sulfide, odorous volatile organic compounds, and greenhouse gases emissions from swine manure" (2019). Graduate Theses and Dissertations. 17743.