Rural communities are affected by gaseous emissions from intensive livestock production. Practical mitigation technologies are needed to minimize emissions from stored manure and improve air quality inside barns. In our previous research, the one-time surficial application of biochar to swine manure significantly reduced emissions of NH₃ and phenol. We observed that the mitigation effect decreased with time during the 30-day trials. In this research, we hypothesized that bi-weekly reapplication of biochar could improve the mitigation effect on a wider range of odorous compounds using a larger scale and longer trials. The objective was to evaluate the effectiveness of biochar dose and reapplication on mitigation of targeted gases (NH₃, odorous, volatile organic compounds VOCs, odor, greenhouse gases (GHG)) from stored swine manure on a pilot-scale setup over 8-weeks. The bi-weekly reapplication of the lower biochar dose (2 kg/m²) showed much higher significant percentage reductions in emissions for NH₃ (33% without and 53% with reapplication) and skatole (42% without and 80% with reapplication), respectively. In addition, the reapplication resulted in the emergence of a statistical significance to the mitigation effect for all other targeted VOCs. Specifically, for indole, the percentage reduction improved from 38% (p = 0.47, without reapplication) to 78% (p = 0.018, with reapplication). For phenol, the percentage reduction improved from 28% (p = 0.71, without reapplication) to 89% (p = 0.005, with reapplication). For p-cresol, the percentage reduction improved from 31% (p = 0.86, without reapplication) to 74% (p = 0.028, with reapplication). For 4-ethyl phenol, the percentage emissions reduction improved from 66% (p = 0.44, without reapplication) to 87% (p = 0.007, with reapplication). The one-time 2 kg/m² and 4 kg/m² treatments showed similar effectiveness in mitigating all targeted gases, and no statistical difference was found between the dosages. The one-time treatments showed significant percentage reductions of 33% and 42% and 25% and 48% for NH₃ and skatole, respectively. The practical significance is that the higher (one-time) biochar dose may not necessarily result in improved performance over the 8-week manure storage, but the bi-weekly reapplication showed significant improvement in mitigating NH₃ and odorous VOCs. The lower dosages and the frequency of reapplication on the larger-scale should be explored to optimize biochar treatment and bring it closer to on-farm trials.

中文翻译：

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用生物炭减轻储存猪粪中的气体排放：剂量和再施用对中试规模的影响

农村社区受到集约化畜牧生产的气体排放的影响。需要实用的缓解技术来最大程度地减少粪便中的排放物并改善谷仓内的空气质量。在我们以前的研究中，一次性将生物炭应用于猪粪便显着减少了NH ₃和苯酚的排放。我们观察到，在30天的试验中，缓解效果随时间而降低。在这项研究中，我们假设每两周重新使用生物炭可以使用更大规模和更长时间的试验来提高对更广泛的臭味化合物的缓解效果。目的是评估生物炭剂量和再施用对缓解目标气体（NH ₃储存在猪粪中的气味，挥发性有机化合物，挥发性有机化合物，气味，温室气体（GHG）），试验规模为8周。较低的生物炭剂量（2 kg / m ²）每两周重新施用表明，NH ₃（不施用33％，再施用53％）和粪臭素（不施用42％，再施用80％）的排放显着更高的百分比降低， 分别。此外，重新应用对所有其他目标VOC的缓解效果产生了统计学意义。具体而言，对于吲哚，减少的百分比从38％（p = 0.47，不重新应用）提高到78％（p = 0.018，重新应用）。苯酚的减少百分比从28％改善了（p= 0.71（不重新应用）至89％（p = 0.005，重新应用）。对于对甲酚，减少的百分比从31％（p = 0.86，不重新应用）提高到74％（p = 0.028，重新应用）。对于4-乙基苯酚，减排百分比从66％（p = 0.44，不重新应用）提高到87％（p = 0.007，重新应用）。一次性2 kg / m ²和4 kg / m ²处理在缓解所有目标气体方面显示出相似的效果，并且在剂量之间没有统计学差异。一次性处理显示NH _3的百分比显着减少了33％，42％，25％和48％和skatole。实际的意义是，较高的（一次性）生物炭剂量可能不一定会导致在8周的粪便存储中性能得到改善，但每两周重新施用显示出在减少NH ₃和有气味的VOC方面的显着改善。应该探索较低的剂量和较大规模的重新施用频率，以优化生物炭处理并使之更接近农场试验。