Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, Viale G. Fanin, 40, 40127 Bologna, Italy.
Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, Viale G. Fanin, 40, 40127 Bologna, Italy.
Sci Total Environ. 2020 Jan 1;698:134198. doi: 10.1016/j.scitotenv.2019.134198. Epub 2019 Sep 2.
Wet and dry-batch anaerobic digestion, and composting are common technologies in food waste (FW) management, resulting in different outputs. However, the effects of composting on carbon dioxide (CO) emissions, nitrogen (N) and phosphorus (P) fertilizing capacity in view of closing nutrient cycle are still poorly investigated. In this work, two FW anaerobic digestates from the wet (D) and dry-batch process (D), and their respective composts (C and C) were tested in a soil incubation (84 days at 25 °C) to assess CO emissions in comparison with a mixed (animal slurry/energy crop) digestate (BD) and a reference municipal solid waste compost (MSWC). The same products were also tested for the relative P efficiency (RPE) in soil, in comparison with a chemical-P source (30 mg P kg). Lastly, the apparent recovery fraction of N (N-ARF) from the five organic products was determined in a pot test with ryegrass (84 days; 300 kg available N ha), compared to a chemical fertilizer (NPK). Composting strongly reduced net-CO emissions compared to the two digestates (625 vs. 2850 mg CO kg soil). Oppositely, composting very modestly influenced RPE that ranged around 100-90% in D and C, and ≈30% in D and C. Moreover, composting did not significantly reduce N-ARF that ranked in descending order as follows: NPK (77.5%) > D = BD (17.7%) ≥ C (14.7%) > MSWC (3.6%) > D (1.2%) > C (-3.1%). Composting was shown a reliable strategy for FW digestate management, as it reduces potential CO emission without affecting these products' N- and P-fertilizing capacity.
湿垃圾和干垃圾分批厌氧消化以及堆肥是食品垃圾（FW）管理中常见的技术，会产生不同的产物。然而，堆肥对二氧化碳（CO）排放、氮（N）和磷（P）施肥能力的影响，鉴于养分循环的封闭性，仍未得到充分研究。在这项工作中，两种 FW 厌氧消化物（湿式[D]和分批干垃圾[D]）及其各自的堆肥（C 和 C）在土壤培养中进行了测试（84 天，25°C），以评估与混合（动物粪便/能源作物）消化物（BD）和参考城市固体废物堆肥（MSWC）相比 CO 的排放。还对同一产品在土壤中的相对磷效率（RPE）进行了测试，与化学磷源（30mg P kg）进行了比较。最后，在一个黑麦草（84 天；300kg 有效 N ha）的盆栽试验中，与化肥（NPK）相比，从五种有机产品中测定了表观氮回收率（N-ARF）。与两种消化物（2850mg CO kg 土壤）相比，堆肥强烈降低了净 CO 排放（625mg CO kg 土壤）。相反，堆肥对 RPE 的影响非常小，D 和 C 中的 RPE 约为 100-90%，而 D 和 C 中的 RPE 约为 30%。此外，堆肥并没有显著降低 N-ARF，其降序排列如下：NPK（77.5%）>D=BD（17.7%）≥C（14.7%）>MSWC（3.6%）>D（1.2%）>C（-3.1%）。堆肥被证明是 FW 消化物管理的一种可靠策略，因为它减少了潜在的 CO 排放，而不会影响这些产物的 N 和 P 施肥能力。
