不同物料堆肥腐熟程度的紫外-可见光谱特性表征

水溶性有机物(DOM)紫外-可见吸收光谱特性是评价堆肥腐熟度重要方法之一，但由于紫外-可见吸收光谱指标众多，单指标评价具有较大局限性。因此，本研究开展了影响堆肥腐熟度的关键紫外-可见光谱特性指标识别，并采用化学剂量学方法评价了不同来源堆肥腐熟程度。与传统单一物料评价相比，优选的评价指标及评价方法更具普适性。不同物料堆肥过程中DOM紫外-可见光谱特性分析结果表明，SUVA₂₅₄和SUVA₂₈₀值呈明显的增加趋势，E₂₅₀/E₃₆₅和E₄/E₆值呈相反的趋势，而A_226～400，S_275～295，S_350～400值则在堆肥末期变化显著。相关分析表明不同紫外-可见光谱参数(E₂/E₄和E₂₃₅/E₂₀₃除外)彼此之间相关性显著;主成分分析显示，DOM紫外-可见光谱指标A_226～400, SUVA₂₅₄, S_350～400, SUVA₂₈₀, S_275～295可作为堆肥腐熟程度关键影响评价指标。在此基础上，采用筛选的特性指标对堆肥末期进行聚类分析，可将九种不同来源堆肥分为两大类，第一类为猪粪、鸡粪、污泥、秸秆、园林垃圾、果蔬及生活垃圾等腐熟程度较低的堆肥;第二类为杂草和厨余腐熟程度较高的堆肥。

Using UV-Vis Absorbance for Characterization of Maturity in Composting Process with Different Materials

The present study was conducted to assess the degree of humification in DOM during composting using different raw materials, and their effect on maturity of compost based on UV-Vis spectra measurements and chemometrics method. The raw materials of composting studied included chicken manure, pig manure, kitchen waste, lawn waste, fruits and vegetables waste, straw waste, green waste, sludge, and municipal solid waste. During composting, the parameters of UV-Vis spectra of DOM, including SUVA₂₅₄, SUVA₂₈₀, E₂₅₀/E₃₆₅, E₄/E₆, E₂/E₄, E₂/E₆, E₂₅₃/E₂03, E₂₅₃/E₂₂₀, A_226～400, S_275～295 and S_350～400 were calculated, Statistical analysis indicated that all the parameter were significantly changed during composting. SUVA₂₅₄ and SUVA₂₈₀ of DOM were continuously increased, E₂₅₀/E₃₆₅ and E₄/E₆ were continuously decreased in DOM, while A_226～400, S_275～295 and S_350～400 of DOM at the final stage were significantly different with those at other stages of composting. Correlation analysis indicated that the parameters were significantly correlated with each other except for E₂/E₄ and E₂₃₅/E₂₀₃. Furthermore, principal component analysis suggested that A_226～400, SUVA₂₅₄, S_350～400, SUVA₂₈₀ and S_275～295 were reasonable parameters for assessing the compost maturity. To distinguish maturity degree among different composts, hierarchical cluster analysis, an integrated tool utilizing multiple UV-Vis parameters, was performed based on the data (A_226～400, SUVA₂₅₄, S_350～400, SUVA₂₈₀ and S_275～295) of DOM derived from the final stage of composting. Composts from different sources were clustered into 2 groups. The first group included chicken manure, pig manure, lawn waste, fruits and vegetables waste, green waste, sludge, and municipal solid waste characterized by a lower maturity degree, and the second group contained straw waste and kitchen waste associated with a higher maturity degree. The above results suggest that a multi-index of UV-Vis spectra could accurately evaluate the compost maturity, and A_226～400, SUVA₂₅₄, S_350～400, SUVA₂₈₀ and S_275～295 of DOM could serve as primary parameters when the compost maturity was assessed using UV-Vis spectra.