厨余垃圾水热转化制取有机肥的试验研究

AN EXPERIMENTAL STUDY ON PRODUCTION OF ORGANIC FERTILIZER FROM FOOD WASTE BY HYDROTHERMAL CONVERSION

水热技术在处理厨余垃圾时具有高效、清洁、安全等优势,近年来受到国内外学者的广泛关注。以模拟厨余垃圾为对象,开展了厨余垃圾水热转化制取有机肥的试验研究,试验工况为反应温度175~235℃,停留时间20~80 min。结果表明:与传统的堆肥处理相比,由于没有微生物损耗,厨余垃圾水热处理后肥效更高,有机质、总养分含量分别为55.77%~72.92%、7.39%~8.20%,远高于NY 525—2021《有机肥料》标准值。在一定温度范围内,水热过程能够促进腐植酸的形成,在205℃、40 min工况下腐植酸含量达到21.70%,腐殖化指数(胡敏酸/富里酸)为1.67,表现出极高的腐熟度。水热处理能够促进单价金属盐的迁移,大部分单价金属盐(Na、K)通过反应后从固相迁移到液相中,而大部分多价金属盐(Ca、Mg、Fe)则保留在固相中。

Hydrothermal treatment has the advantages of high efficiency,cleanness,and safety in food waste disposal,which has been widely concerned by global scholars in recent years.In this paper,the experimental study on the production of organic fertilizer from simulated food waste by hydrothermal conversion was carried out at a temperature of 175 to 235℃,and a retention time of 20 to 80 min.Results showed that the fertilizer efficiency of food waste after hydrothermal treatment was higher than traditional composting treatment.The content of organic matter and total nutrients were 55.77%to 72.92%and 7.39%to 8.20%respectively,far higher than the limiting values in the Standard of Organic Fertilizer(NY 525—2021).Hydrothermal process could promote the formation of humic acid.With a retention time of 40 min at 205℃,the humic acid content reached 21.70%,and the humification index(the ratio of humic to fulvic)could be 1.67,reflecting a very high degree of maturity.Hydrothermal treatment could enhance the migration of salts.Most monovalent metals(potassium and sodium)resided into the liquid phase from the solid phase,while most multivalent metals(calcium,magnesium,and iron)remained integrated within the solid phase.