Composting with negative pressure aeration for the mitigation of ammonia emissions and global warming potential. (10th September 2018)

• Record Type: Journal Article
• Authors: Wang, Xuan; Bai, Zhaohai; Yao, Ying; Gao, Binbin; Chadwick, David; Chen, Qing; Hu, Chunsheng; Ma, Lin
• Is Part Of: Journal of cleaner production. Volume 195(2018)
• Page Start: 448
• Page End: 457
• Publication Date: 2018-09-10
• Subjects: Composting -- Negative pressure -- Biodegradation -- NH3 emission -- Greenhouse gas; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2018.05.146
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Positive forced aeration is widely used in industrial composting plants to supply sufficient oxygen, accelerating compost maturity. However, this technology results in significant gaseous emission, especially NH3 and GHGs emissions. To reduce gaseous emissions and investigate aeration efficiency, negative pressure aeration was used during cattle manure + corn stalk composting in 50 L-scale reactors. Composting with negative pressure aeration at three different flow rates (0.25, 0.50 and 0.75 L/min/kg dry weight, named Negative-L, Negative-M and Negative-H treatments) were conducted. Treatment with positive pressure aeration was set as a control (Positive-M, with flow rate at 0.50 L/min/kg dry weight). The results showed that negative pressure aeration changed the temporal distribution of oxygen and temperature. With the same flow rate, the Negative-M treatment maintained a longer thermophilic period, accelerating organic matter degradation (47.6% in treatment Negative-M and 41.4% in Positive-M) and the maturity of feedstock (germination index was 105.9% in Negative-M and 58.5% in Positive-M). Ammonia emissions were significantly reduced by composting with negative pressure aeration. During composting, 36.7%, 15.8%, 16.8% and 16.0% of the initial total nitrogen was lost via NH3 volatilizations in the Positive-M, Negative-L, Negative-M and Negative-H treatments, respectively, indicating NH3 emissions were reduced by ∼55% compared to the positive pressure aeration treatment. Even though both CH4 and N2 O emission were greater from the negative pressure aeration treatments, the global warming potential was significantly reduced in treatments with negative pressure aeration because of the lower NH3 emission (an indirect N2 O source). This indicates the benefit of NH3 emission mitigation was larger than the increase in CH4 and N2 O emissions. Highlights: Oxygen and temperature distribution were explored in negative pressure composting. Negative aeration composting increases organic matter degradation. Negative aeration composting reduced NH3 loss but promoted CH4 and N2 O emissions. Benefit of NH3 conservation was larger than the increase in CH4 and N2 O emissions.