不同通风策略下大规模鸭粪堆肥的腐熟和光谱特征

Maturing and spectral characteristics of large-scale duck manure composting under different ventilation strategies

[目的]鉴于鸭粪处理的固有挑战,有效的通风措施是鸭粪工业堆肥过程成功的关键。这项开创性的研究旨在评估来自鸭粪和蘑菇废弃物堆肥的腐熟度和稳定性。本研究进一步探讨了各种通风策略在促进堆肥过程中有机物分解和转化方面的有效性和效率。[方法]将鸭肥和蘑菇废弃物按干重比为2∶1(C/N约为21.15)混合进行堆肥试验。堆肥采用梯形桩,每桩体积5.6 m^(3),采用管道通风。堆肥试验包括4个通气时间处理,分别为10、20、30、60 min/d(分别记作C1、C2、C3和C4处理)。主要研究了堆肥过程中物理化学特性、紫外-可见光谱、X射线衍射(XRD)和红外光谱(IR)的变化特征。[结果]在堆肥第5天和第6天,堆肥进入嗜热期,持续17天,第15天达到50℃。在堆肥前5天,堆肥pH从8.5迅速上升到12.3,可能是由于鸭粪蛋白质的分解,然后在接下来的20天里逐渐下降,在28~30天急剧下降,之后逐渐下降。在高温期(第17天)后,堆肥C1、C2、C3和C4处理的含水量较堆肥初期分别减少了45.9%、46%、44.7%和43%。C3和C4处理的TC值远低于C1和C2。所有堆肥处理的紫外吸收均随波长的增加而降低。在X射线衍射图中存在部分纤维素特征峰(2θ=26.56°)。这些样品含有更多的结晶和“无定形”纤维素、木聚糖和其他多糖。在200~220 nm光谱范围内,硝酸盐和羧基类化学物质的吸收速度比芳香族或不饱和分子快。堆肥的吸收率随初始碳氮比和堆肥过程的持续时间而变化。相反,在460~480 nm处的吸光度表明有机材料的腐殖质化。Q2/6或Q4/6值越低,表明有机物腐殖化程度越高和越多的有机物缩合成芳香族化合物。在红外光谱中,整个堆肥过程中与有机或无机官能团相关的所有条带的强度都有明显的变化。红外光谱显示出一个宽峰,中心波数为3400 cm^(-1),表明存在与羟基(OH)基团和水分子相关的拉伸振动。在3000~2800 cm^(-1)的光谱范围内,可以观察到一个与有机化合物所表现出的疏水特性相关的现象。在2900~2850 cm^(-1)处存在的条带可以归因于C-H脂肪族基团和醛基基团(CHO)的伸缩振动。初始堆肥样品和C1、C2、C3、C4的红外光谱在堆肥过程中发生了显著变化。由于这些变化,红外光谱吸收带发生了显著的变化,表明相关的物质结构发生了变化。因此,C3和C4在堆肥过程中表现出较高程度的稳定性。[结论]65天的堆肥试验显示,在整个堆肥过程中,温度发生变化,通风60 min/d的堆肥最高温度高于通风10 min/d的堆肥。在堆肥过程中,随着通气量的增加,pH呈下降趋势,因此,日通风30~60 min的堆肥pH较低。堆肥过程中,堆料C/N逐渐降低,表明纤维素活性增加。XRD光谱显示峰值强度降低,反映了纤维素的分解。日通风30~60 min堆肥表现出较高的成熟度,突出了通风对成功堆肥的重要性。

[Objectives]Given the inherent challenges in handling duck manure,effective ventilation measures are pivotal for the success of industrial composting process of duck manure.This pioneering investigation aimed to assess the maturity and stability of compost derived from the challenging composition of duck manure and mushroom waste.The study further scrutinized the efficacy and efficiency of various ventilation strategies in promoting the decomposition and transformation of organic matter during composting.[Methods]Duck manure and mushroom waste were blended in dry weight ratio of 2∶1(C/N ratio about 21.15)for composting experiment.The composts were in trapezoidal piles in volume of 5.6 m3 per pile,and pipes were installed for ventilation.Four ventilation duration treatments were included,as 10,20,30,and 60 min/d(denoted as C1,C2,C3,and C4,respectively).The changes that occurred during composting were investigated through physiochemical properties,recording of UV-visible spectroscopy,X-ray diffraction(XRD),and infrared spectroscopy(IR).[Results]On the 5th and 6th day,compost mixtures entered thermophilic phase,which lasted 17 days and reached 50℃on 15th day.pH climbed quickly from 8.5 to 12.3 in first 5 days due to duck manure protein breakdown,then progressively declined over next 20 days,precipitating between days 28 and 38 and then gently dropping until the compost concluded.After the high-temperature phase(day 17),compost piles C1,C2,C3,and C4 lost 45.9%,46%,44.7%,and 43%of their starting moisture content.C3 and C4 exhibited much lower total carbon values than C1 and C2.UV absorption decreased with wavelength in all composts.Peaks presented in cellulose fraction of X-ray diffractograms(2θ=26.56°).These samples had more crystalline and“amorphous”cellulose,xylan,and other polysaccharides.Nitrates and carboxylic chemicals absorbed faster than aromatic or unsaturated molecules in the 200-220 nm spectral range.Double bonds C=C,C=O,and N=N caused the latter group’s absorption at 250-300 nm.The absorption rate of compost was subject to variation contingent upon either initial C/N ratio or the duration of the composting process.Conversely,the absorbance at 460-480 nm indicated the humification of organic materials.Low ratios of Q2/6 or Q4/6 indicated humification process and condensation of organic matter into aromatic compounds.In IR,throughout the composting process,there was a noticeable alteration in the intensity of all bands associated with organic or inorganic functional groups.The infrared spectra exhibited a broad peak with a central wavenumber of 3400 cm-1,indicating the presence of stretching vibrations associated with hydroxyl(OH)groups and water molecules.Within the spectral range of 3000 to 2800 cm-1,an observable phenomenon could be observed that pertained to hydrophobic characteristics exhibited by organic compounds.The presence of bands at 2900-2850 cm-1 could be attributed to the stretching vibrations of C-H aliphatic groups and aldehyde group(CHO).IR of the initial compost samples and C1,C2,C3 and C4 significantly changed during composting.There was a significant change in absorption bands due to these changes,indicating a change in structures that contribute to absorption.As a result,C3 and C4 exhibited a higher degree of stability during composting.[Conclusions]Over the 65 days of composting,the compost temperature kept varying,with ventilating 60 min/d reaching the highest temperature and 10 min/d at the lowest.pH levels decreased over time due to increased ventilation,resulting in lower values for ventilating 30–60 min/d.The C/N ratio decreased gradually,indicating increased cellulose activity.XRD spectra demonstrated reduced peak intensity,reflecting cellulose decomposition.Ventilating 30–60 min/d treatment exhibited higher compost maturity,highlighting the importance of ventilation in successful composting.