UBC Theses and Dissertations
Effects of bioadditive with yeast and zeolite on the performance and odor emission from poultry manure composting process Wen, Zhiping (Simon)
Objectives of this thesis research are to determine the effectiveness of the bioadditive in reducing odor emissions, to delineate the circumstances or operating conditions under which the bioadditive would be effective, and to determine how the use of the bioadditive would affect the thermal performance of the composting process and the finished compost product. In tests performed using small bioreactors, the high dosage of the bioadditive at 10% w/w resulted in consistently greater odor removal efficiency, when compared to the low dosage at 1% w/w. However, for larger enclosed bioreactors, the bioadditive did not significantly reduce the odor levels in comparison with the control treatment. With pre-drying of the poultry manure, the bioadditive led to greater odor removal versus the control treatment on Day 2, but the reverse trend was observed and odor levels became significantly higher on Days 4 and 8 for the bioadditive treatment. Hence, pre-drying of poultry manure was not effective in eliminating the odorous volatile organic compounds from the manure, thus resulting in an increase in odor emission after the initial two days of composting. Inocula in the form of recycled compost, with previous bioadditive enhancement during the curing phase of the composting process, induced greater odor removal efficiencies, but again only up to Day 2 relative to the control treatment, which used the inocula but without previous bioadditive enhancement. Nevertheless, both experimental treatments demonstrated a significant reduction of odors, versus the treatment without using recycled compost at all as inocula, thus reaffirming the fact that recycled compost could be very effective in odor control for composting. The bioadditive had similar effects on odor removal efficiencies when poultry manure was co-composted with biosolids, versus using manure alone as the composting substrate. The thermal performance of the composting process was improved with the application of the bioadditive. The treatment with higher dosage reached thermophilic temperatures sooner than the other treatments and the high temperatures stayed for a longer time period. Similarly, treatments with bioadditive-enhanced inocula had consistently better thermal performance. Composting without pre-drying of manure was also observed to perform better than that with the manure undergoing a pre-drying process. Higher seed germination index was observed for the compost product with the application of the bioadditive, implying that it is beneficial for compost maturation.
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