Changes in maturity indicators during the degradation of organic wastes subjected to simple composting procedures

Selected maturity indicators were monitored over a period of 335 days during the degradation of organic wastes subjected to four simple composting procedures, which varied in raw material (garden refuse with and without market refuse) and turning frequency (0×, 6×). All procedures produced mature composts. The inclusion of market refuse and frequent turning generally increased the cation exchange capacity of compost on an ash-free basis. Until day 118 of the composting process, compost samples which contained market refuse in their raw material mixture had the lowest redox potentials after anaerobic incubation. Cress grown on these composts also produced the lowest fresh mass. At a later stage of the composting process, the same composts displayed increased cellulolytic activity. Frequent turning of the compost heaps resulted in greater fluorescein diacetate hydrolysis, a greater occurrence of low-molecular-weight humic compounds and, occasionally, an inhibition of cellulolytic activity. The arginine ammonification assay gave information on the N-status of the composts, rather than on the compost maturity, and suggested that all the composts could be safely applied to soil with no risk of microbial immobilisation of soil N.     

Feedstock Carbon Influence on Compost Biochemical Stability and Maturity

Quantity and quality of readily degradable carbon influences the composting process especially for compost mixture high in lignocellulotic material. Effects of carbon source on stability and maturity of compost from in-vessel systems are poorly understood. Research was conducted to investigate the effects of carbon composition of feedstock on the evolution of stability indices and reliability of maturity tests for accelerated vessel composting systems. Rice straw, sugarcane bagasse, and coffee hulls were composted in a modified rotary in-vessel composter amended with either cattle or sheep manure. Distinct evolution patterns were observed across carbon sources for temperature, with the sugarcane compost never attaining thermophilic temperatures. Time to peak temperature and return to ambient were significantly different between the rice and coffee compost. Comparatively, organic matter degradation followed a similar pattern for all carbon sources, although rice straw showed the faster degradative rate and coffee hulls the greatest overall loss. Both pH and electrical conductivity were inappropriate stability indices across carbon sources, while the NH₄⁺/NO₃^? ratio was lower than the threshold from week 1. The Solvita® maturity test was the best suited quality indicator and was related to compost respiration. The rice compost at week 12 was the only mature compost with an index value of 7. However, the coffee compost was in the curing stage with a value of 6. In vitro phytotoxicity assays on hot pepper contrasted the Sovita® interpretation for rice compost, which showed the lowest germination index. All compost had a stimulatory effect on cucumber seeds. In vivo seeding assays corroborated in vitro results with rice compost showing the greatest negative effect, augmented at 100% compost inclusion. Carbon source significantly influenced compost stability and maturity indices, which suggests that greater attention should be directed to quality indices in relation to feedstock composition.     

Molecular characterization of compost at increasing stages of maturity. 2. Thermochemolysis-GC-MS and 13C-CPMAS-NMR spectroscopy

Off-line pyrolysis TMAH-GC-MS (thermochemolysis) and solid-state 13C NMR spectroscopy were applied for the direct molecular characterization of composted organic biomasses after 60, 90, and 150 days of maturity. Off-line thermochemolysis of both fresh and mature composts released various lignin-derived molecules, the quantitative measurement of which was used to calculate structural indices related to compost maturity. These indicated that most of the molecular transformation occurred within the first 60 days of the composting process, whereas slighter molecular variations were observed thereafter. Both 13C NMR spectra and offline programs suggested that the process of compost maturity was characterized by a progressive decrease of alkyl components, whereas cellulose polysaccharides appeared to be more resistant and began to be transformed at a later composting period. The main components of the final mature compost were lignocellulosic material and hydrophobic alkyl moieties, in as much as that commonly found in well-humidified organic matter of soils and sediments. The persistence of untransformed lignin-derived products and di- and triterpenoids throughout the maturity period suggested that these molecules are useful markers to both evaluate compost origin and trace its fate in the environment. Thermochemolysis provided the same characterization of molecules either unbound or bound to the compost matrix as that reached by a previously applied sequential chemical fractionation of the same compost materials, thereby indicating that thermochemolysis is a more rapid and equally efficient tool to assess compost molecular quality.     

微生物菌剂对油枯堆肥过程中理化性质的影响研究

以油枯为基本原料,采用好氧堆肥方式进行堆肥试验,研究了添加4种不同微生物菌剂的条件下,油枯-稻壳-甘蔗渣堆肥体系中pH、C/N、水溶性NO3--N、水溶性NH4＋-N中的动态变化规律及菌剂对高温堆肥腐熟进程的影响。结果表明,添加菌剂能有效缩短堆肥到达高温的时间,延长高温分解阶段,加快物料水溶性NH4＋-N和C/N降低,pH和水溶性NO3--N含量升高,加快了油枯堆肥腐熟化进程。添加VT菌剂的堆肥处理相比其他在堆肥15d后最先进入高温分解阶段,高温持续时间为10d,提早5d腐熟,水溶性NO3--N含量从71.41mg.kg-1增加到887.4mg.kg-1,C/N的降低有效促进了NH4＋-N向NO3--N的转化,加快了油枯堆肥化进程,有助于提高堆肥腐熟化程度,说明添加VT菌剂的堆肥腐熟效果相对显著。     

Effects of aeration and moisture during windrow composting on the nitrogen fertilizer values of dairy waste composts

The objective of this work was to evaluate the effects of turning and moisture addition during windrow composting on the N fertilizer values of dairy waste composts. Composted-dairy wastes were sampled from windrow piles, which received four treatments in a 2×2 factorial of turning (turning vs. no turning) and moisture addition (watering vs. no watering) at two stages of maturity (mature vs. immature). Composts were characterized for their chemical properties. An 84-day laboratory incubation of soils with addition of the composts at two levels was conducted to evaluate the inorganic N accumulation patterns from the variously treated composts. Chemical analyses of variously treated composts did not differ between compost treatments or maturity. In contrast, the inorganic N accumulation patterns differed between soils that received immature versus mature turned composted-dairy wastes. The results suggested that turning was a more important factor than moisture addition affecting the composting process. There was no significant difference in inorganic N accumulation patterns among soils that received different immature composts, while the N accumulation patterns observed for soils that received different mature composts depended on compost treatments. Soils amended with mature composts treated by frequent turning had higher N mineralization potentials (N₀), mineralization rate constants (K), and initial potential rates (N₀K) in comparison to soils with composts that had not been turned. Soils with mature composts treated by watering had a higher N₀, lower K, and therefore similar N₀K when compared to soils with composts that had not been watered. Soils that received mature composts treated by watering and frequent turning had higher N mineralization potentials and N₀ to total organic N ratios than soil alone, which suggested that intensive management of composting would ensure positive N fertilizer values of dairy waste composts, if the appropriate composting duration is completed.     

Evaluation of a new composting method in terms of its biodegradation pathway and assessment of compost quality,maturity and stability

The need for scientific composting methods for effective utilization of organic waste is increasing day by day. In this respect, a new process called the Novcom composting method is being increasingly adopted by the organic tea planters of Assam and Darjeeling (India) for large-scale composting. Study of the biodegradation process under this method and quality evaluation of the end product was carried out at Maud tea estate (Assam) during 2008–2009 and 2009–2010. Generation of high temperatures (>65°C) within the compost heap during the biodegradation process provided an indication regarding the destruction of pathogens and weed seeds in the composted material. Samples collected on day 0, 7, 14, 21 and 30 of composting, were analyzed for physicochemical properties, nutrient status, microbial population, stability and phytotoxicity parameters. The most significant finding was the high microbial population (in the order of 10¹⁶ cfu g^?1) in the final product, which was generated naturally during biodegradation. Assessment of the maturity and stability parameters of the compost indicated that biodegradation was complete in ～3 weeks. The study provided an indication of the potential of the Novcom composting method for the production of good quality, stable and mature compost, within a short period.     

添加不同辅料对污泥堆肥腐熟度及气体排放的影响

选择玉米秸秆和木本泥炭两种辅料添加至脱水污泥中进行联合好氧堆肥,研究了秸秆和木本泥炭作为添加剂对污泥堆肥腐熟度和堆肥过程中气体排放(NH_3、CH_4和N_2O)的影响。两种辅料添加量均为初始物料的15%,堆肥在60 L的密闭反应器中共持续35 d。研究结果表明,秸秆作为添加剂与污泥联合堆肥,堆肥产品可以达到卫生标准和腐熟标准。添加秸秆处理整个堆肥过程中累积NH_3、CH_4和N_2O排放量分别为2.2、0.14和0.09 g/kg,NH_3和CH_4排放主要发生在堆肥的升温期和高温期,N_2O排放主要发生在堆肥的后腐熟阶段。添加木本泥炭作为添加剂不能成功启动堆肥,整个堆置过程中未检测到NH_3和CH_4排放,但是在堆肥前期有大量N_2O产生。对于添加秸秆的处理,CH_4、N_2O和NH_3对总温室气体排放的贡献率分别为45%,36%和19%,CH_4所占比重最高。     

采用EEM-FRI方法研究黑曲霉对牛粪堆肥腐熟及纤维素降解影响

为了优化堆肥工艺,提高堆肥产品质量,研究黑曲霉对牛粪堆肥腐熟度和纤维素降解的影响.该研究以牛粪为原料,小麦秸秆为辅料,以不添加黑曲霉为对照,分别添加1％、2％和3％的黑曲霉进行好氧堆肥,研究了黑曲霉不同添加量对腐熟度指标、养分含量、腐殖质组成以及纤维素组分的影响,并采用激发发射荧光光谱结合荧光区域积分(Excitati...     

Evaluation of sewage sludge-based compost by FT-IR spectroscopy

The aerobic batch composting fermentations of sewage sludge with wood chips and maturity compost as co-composting additives were carried out in an open type lab-scale reactor. Fourier transform infrared spectroscopy (FT-IR) spectroscopy was used to monitor the composting process, evaluate the degradation rate and thus determine the maturity. Although the composition of the input mixture strongly affects the shape of the infrared (IR) spectra, typical bands of components can be selected and used to follow the composting process.

The appearance, shape and intensity of the nitrate band at 1384 cm^− 1 was well pronounced and evident for a sewage sludge-based compost maturity. An increase of the peak ratio 1384 / 2925 and decrease of 2925 / 1034, 1034 / 1384 correlated with the degree of decomposition. For the composting mixture under study the peak ratios 1034 / 1384 and 1384 / 2925 were more demonstrative. Considering the influence of the composting mixture (components and their ratio) on the shape of the FT-IR spectra the nitrate band at 1384 cm^− 1 can be overlapped by other absorption bands (e.g. lignin bands in 1300–1400 cm^− 1 region) thus appearing in the spectra as a shoulder, and therefore the ratios 1384 / 2925 and 1034 / 1384 become unusable to evaluate the maturity.

FT-IR spectroscopy is a quick and useful method to monitor the composting process; however any particular composting mixture needs preliminary studies of the spectra. Consequently, the most appropriate criteria describing the process (e.g. band ratios, shape and intensity of nitrate band) should be selected and the time / peak ratio curves recorded for a compost mixture under study. Afterwards monitoring of the composting process can be based on the comparison of the controls and definite samples.     

碳氮比对鸡粪堆肥腐熟度和臭气排放的影响

为确定鸡粪堆肥最优碳氮比（C/N比），该研究以新鲜鸡粪为堆肥原料，添加玉米秸秆调节初始C/N比为14、18和22进行好氧堆肥，研究不同C/N比对鸡粪堆肥腐熟度和臭气排放（NH3和H2S）的影响。结果表明：C/N比为14的处理堆肥产品未腐熟，C/N比为18和22的处理均达到腐熟。C/N比为18的处理NH3累积排放量和总氮（TN）损失率最高；C/N比为18～22时，C/N比越高，NH3累积排放量和TN损失率越低。C/N比为14的处理H2S累积排放量和总硫（TS）损失率最高；C/N比为18和22的两个处理，H2S累积排放量显著降低，且无显著差异。此外，C/N比为18处理的微生物群落多样性在整个堆肥过程中显著高于C/N比为14和22处理。堆肥的理化指标、臭气排放与微生物群落之间的相关性分析表明，高温、高pH和缺氧环境会增加Firmicutes丰度，进而促进NH3和H2S的排放，相反地，低温、低pH和氧气充足的环境更有利于Actinobacteria增殖，有利于减少NH3和H2S的排放。综合考虑堆肥产品腐熟度和臭气减排效果，建议低C/N比鸡粪堆肥的初始C/N比为18～22。当秸秆资源不足时，建议初始C/N比为18；秸秆资源充足时，建议初始C/N比为22。     

Nematode faunal response to long-term application of nitrogen fertilizer and organic manure in Northeast China

Nematode faunal response to the long-term (20-year) application of nitrogen fertilizer and organic manure was monitored in a Hapli-Udic Cambosol of Northeast China, where no fertilizer (C), nitrogen fertilizer (N), organic manure (M) and nitrogen fertilizer plus organic manure (N + M) treatments were compared. The obtained results showed that total nematode abundance responded positively to the M and N + M treatments. The numbers of Acrobeloides increased in the M and N + M treatments at maize jointing and booting stages, and those of Aphelenchoides were higher in the N + M treatment than in the N treatment at maize ripening stage. Early in the growing season, the numbers of bacterivores of cp-1 (cp, colonizer-persister) and cp-2 guilds were higher in the M and N + M treatments than in the N treatment, while those of bacterivores and fungivores of cp-4 guilds were higher in the C treatment than in the N, M and N + M treatments. Except at maize seedling stage, the numbers of fungivores of cp-2 and herbivores of cp-3 guilds were higher in the N + M treatment than in the C treatment. Ratios of the weighted abundance of representatives of specific functional guilds were used as indicators of food web structure, enrichment and decomposition channels. Values of the enrichment index (EI) at maize seedling and jointing stages were higher in the M and N + M treatments than in the C and N treatments, while an opposite trend was observed in the channel index (CI). Higher EI and lower CI suggest an enriched soil food web dominated with bacterial decomposition channels in the M and N + M treatments.     

猪粪堆制过程中主要酶活性变化

通过室内模拟堆肥,研究了以猪粪为主体材料的发酵过程中的生物化学变化特征。结果表明,猪粪在发酵初期(0～25d)的干物质损失在30%左右,而中后期虽然时间较长,但其干物质损失仅占7%。发酵过程中除过氧化氢酶外,各主要酶活性均呈现不断下降并逐步稳定的趋势。发酵周期内多酚氧化酶和蛋白酶活性出现两次高峰,表明了堆肥内不同时期有机碳、含氮化合物分解和腐殖化进程的强度变化。在堆肥快速分解阶段,转化酶活性下降95%,脲酶、纤维素酶活性下降70%以上,且稳定维持在较低水平,以此可作为判定猪粪堆制过程中腐熟程度的定量生化指标。     

秸秆对猪粪静态兼性堆肥无害化和腐熟度的影响

为促进猪粪静态兼性堆肥产品无害化和腐熟,通过添加玉米秸秆调控堆体物理结构特性和碳氮比,采用传统自然发酵方式进行为期90d的静态兼性堆肥试验,分别设置纯猪粪处理(P)和秸秆调控处理(PC)研究静态兼性堆肥过程腐熟度指标、粪大肠菌群以及微生物群落结构演变特征。结果表明,秸秆调控增加了堆体孔隙率(提高19.41%),促进氧气向堆体内部扩散,增强了好氧微生物对有机质的降解,降低NH₄⁺-N,可溶性有机氮(dissolved total nitrogen, DTN)等植物毒性物质含量,提升了堆肥腐熟度,两组处理堆肥产品种子发芽指数分别为40.84%(P)和114.60%(PC)。静态兼性堆肥经过30～40 d自然发酵后,粪大肠菌群数量达到卫生安全标准,堆体温度、NH₄⁺-N和有机酸含量均会影响粪大肠杆菌的活性。堆体中微生物以厚壁菌门、放线菌门、变形菌门等与木质纤维素降解相关的菌门为优势菌门,堆体自上而下由好氧菌属演替为厌氧菌属,并形成好氧、兼性、厌氧的微生物分层。秸秆调控增加了堆体的好氧区域,促进和提高了猪粪...     

Evolution of Organic Matter Within Sixty Days of Composting of Lignocellulosic Food Industry Waste in Malaysia

Empty fruit bunches (EFB), coffee grounds (CG), and palm oil mill sludge (POMS) were composted in the laboratory for 60 days in order to study the composting process of lignocellulosic food industry wastes. In the first part of the experiment, EFB, CG, and POMS were composted alone (composting of single lignocellulosic material), and in the second part, EFB was composted with CG (1EFB:1CG ratio) and POMS (1EFB:1POMS ratio). The effects of different turning frequencies on the physical and chemical properties of composting were observed and its relation with the degradation process was highlighted. Results showed that oil and grease were first degraded, followed by recalcitrant compounds like alpha-cellulose, hemicellulose, and lignin. Cellulose and hemicellulose were degraded mainly during the 60 days of composting, and the progressive reduction of the cellulose/lignin ratio proved that the main evolution of these wastes took place. It was observed that 3, 6, and 9 days of turning frequency did not affect the physicochemical properties of the compost. Composting EFB alone failed to achieve the required quality of maturity compost within 60 days, while CG and POMS recorded low in biological activity. Better results were shown in composting of EFB mixed with coffee grounds and POMS, the C/N ratio dropped to less than 20 by the 8th week of the composting period. Composting of mixed lignocellulosic materials showed larger changes compared to composting of single lignocellulosic material, reaching a C/N ratio below 20 within 8 weeks.     

Molecular characterization of compost at increasing stages of maturity. 1. Chemical fractionation and infrared spectroscopy

Composted organic biomasses at 60, 90, and 150 days of maturity were studied for changes in molecular composition. Compost samples were subjected to a mild sequential fractionation based on (1) organic solvent extraction, (2) transesterification with boron trifluoride in methanol (BF3-CH3OH), and (3) methanolic alkaline hydrolysis (KOH-CH3OH). The general chemical variations in compost residues following fractionation were monitored by DRIFT spectroscopy, whereas the molecular components separated along the fractionation steps were identified by GC-MS. DRIFT spectra suggested a progressive decrease of biolabile compounds such as alkyls, carbohydrates, and proteinaceous materials with compost maturity. Extraction of unbound components in an organic solvent indicated a considerable reduction of linear and branched alkanoic acids, both saturated and unsaturated, n-alkanes, and n-alkanols with enhancing compost maturity. Extracts of weakly bound molecules by transesterification revealed a decrease, with compost maturity, of components from more recalcitrant plant polyesters, such as omega-, di-, and trihydroxy acids, dioic acids, and n-alkanols. Extracts of strongly bound molecules by alkaline hydrolysis indicated a lower decrease of the same components, suggesting their reduced availability when in stable hydrophobic domains of progressively mature compost. The largest decrease in molecular components occurred when compost was stabilized from 60 to 90 days, whereas its composition did not significantly vary after stabilization at 150 days. The molecular structures of a number of steroids and terpenes appeared to be less susceptible to transformation with composting maturity, thereby resulting as useful biomarkers to trace the fate of composted organic matter in the environment. This work showed that a detailed molecular characterization of compost by a stepwise chemical fractionation enables the evaluation of compost maturity and origin of composted biomasses, as well as the identification of environmental tracers.     

两种微生物菌剂对烟草废弃物高温堆肥腐熟进程的影响

以烟草废弃物为主要原料,添加合适比例猪粪进行高温堆肥试验,研究了烟草废弃物堆肥体系中加入两种微生物菌剂（NNY、FB）后的温度、总氮（T-N）、NH4＋-N、C/N、种子发芽指数（GI）的动态变化及其对烟草废弃物堆肥产品品质的影响。结果表明,添加微生物菌剂缩短了烟草废弃物堆肥达到高温的时间,延长了高温分解持续时间,增加全氮含量,加快物料NH4＋-N和C/N比的降低速率,提高种子发芽指数（GI）,加快了烟草废弃物堆肥腐熟化进程。纯烟草废弃物单独堆肥,最高温度为43℃,GI最高为78.4%。添加微生物菌剂NNY、FB的堆肥处理都在堆肥2d后进入高温分解阶段（〉50℃）,高温持续时间分别为15、12d,较仅添加合适猪粪比例处理进入高温分解阶段时间提前2d,高温持续时间分别延长5、2d。至堆肥11d,添加微生物菌剂NNY和FB的堆肥处理种子发芽指数较纯烟草废弃物处理分别增加了185.5%和117.7%,较仅添加合适比例猪粪处理分别增加了41.4%和7.6%。添加NNY、FB微生物菌剂的处理可以显著增加烟草废弃物堆肥产品的N、P、K养分含量,降低堆肥容重,提高堆肥总孔隙度和持水孔隙度,改善了堆肥产品的品质。两种微生物菌剂对烟草废弃物高温腐熟效果较优。     

促腐剂在鸡粪堆肥发酵中的应用研究

选用鸡粪和小麦秸秆为原料进行高温好氧堆肥,研究促腐剂在鸡粪堆肥发酵中的应用。结果表明,接种促腐剂可迅速提高堆肥初期的发酵温度,最高温度超过70℃,但发酵后期降温快,高温加快了堆肥的发酵。发酵20d种子发芽指数达到80%以上;发酵30d含氮量比对照高4.3%,含水量降低3个百分点。综合堆温、C/N、种子发芽指数各项腐熟度指标,接种促腐剂可使鸡粪堆肥腐熟时间比对照提前5d以上。接种促腐剂可降低物料对种子发芽指数的影响,显著缩短发酵时间,加快堆肥物料的水分挥发,使堆肥中的无机营养成分含量相对增加,从而提高鸡粪堆肥的质量。     

Effects of organic mulches on soil microfauna in the root zone of apple: implications for nutrient fluxes and functional diversity of the soil food web

A variety of organic materials (e.g. composts, paper recycling wastes, hay) can be used as in-row mulches in perennial horticultural cropping systems such as high density apple orchards. As organic materials with variable properties, such mulches can be expected to have variable effects on structure of the soil food web and mineralisation of N and P in the root zone. The overall objectives of this study were to: (1) assess the effects of a selection of organic mulches on the abundance of protozoa and nematode trophic groups; (2) use the model of Hunt et al. [Biol. Fertil. Soils 3 (1987) 393] to assess the implications of changes in microfaunal abundance for microbial turnover and N mineralisation; and (3) determine effects of the mulches on nematode indicators of increased microbial production/turnover and functional diversity of the soil food web. Organic mulch treatments commenced in 1994 and included shredded office paper, municipal biosolids, shredded paper applied over municipal biosolids, shredded paper applied over municipal compost, alfalfa hay, and black polyethylene fabric. The control was conventional tree-row weed management with glyphosate. Biosolids and municipal compost treatments were re-applied in 1997. Protozoan abundance was determined in 1998, 1999 and 2000. Nematode community structure was assessed in 1998, 1999, and twice in 2000. Nematode community parameters evaluated included: abundance of bacterivorous, fungivorous, omnivorous and predacious nematodes; abundance of the root-lesion nematode, Pratylenchus penetrans; absolute and relative abundances of enrichment opportunist nematodes (Rhabditidae+Diplogasteridae+Panagrolaimidae); Simpson’s diversity; evenness; and the indices of nematode community enrichment (EI) and structure (SI) described by Ferris et al. [Appl. Soil Ecol. 18 (2001) 13]. Measurements of the abundance of enrichment opportunists and the EI were evaluated as indicators of enhanced nutrient fluxes. Diversity and the SI were evaluated as indicators of changes in functional diversity of the soil food web.The abundance of protozoa and bacterivorous nematodes, and estimated fluxes of N and P through the microfauna, were greater under all combinations of biosolids or municipal compost and shredded paper than under the control and plastic mulch. The abundance of enrichment opportunist nematodes and the EI were also consistently greater under combinations of biosolids or municipal compost and shredded paper. The abundance of enrichment opportunists and EI were both also correlated with leaf P, providing additional evidence to support the use of these parameters as indicators of enhanced turnover of microbial biomass and nutrients. The SI was greatest under shredded paper and shredded paper applied over municipal compost, and least under municipal biosolids and alfalfa hay. Population densities of P. penetrans were reduced under shredded paper mulch relative to the control and biosolids alone.     

微生物菌剂对厨余垃圾堆肥温室气体减排的影响

为对厨余垃圾堆肥过程中的温室气体进行减排,在60 L强制通风静态堆肥装置中进行为期35 d的厨余垃圾和园林废弃物的联合好氧堆肥试验。在堆肥原料中分别添加复合微生物菌剂VT1000（VT）、枯草芽孢杆菌（BS）和地衣芽孢杆菌（BL）三种菌剂,并以不加菌剂的堆肥处理（CK）作为对照,监测堆肥过程中的CH4和N2O排放,以研究不同微生物菌剂对于厨余垃圾堆肥温室气体排放的影响。结果表明：微生物菌剂的添加会加快堆体升温和促进腐熟,同时能够实现不同程度的温室气体减排。堆肥过程中N2O的排放量在总温室气体二氧化碳排放当量中占比远高于甲烷,达到总排放当量的76.83%～88.57%,排放高峰期分别出现在堆肥初期和腐熟期。甲烷的排放高峰期出现在堆肥降温期,累计排放量达到温室气体总排放当量的1.65%～2.40%。各处理的总温室气体排放当量分别为95.84 kg·t-1（CK）、52.31 kg·t-1（VT）、42.03 kg·t-1（BS）和62.49 kg·t-1（BL）。与CK处理相比,BS处理的总温室气体的减排效果最好,减排率为56.15%,BL处理的减排率最低,为34.80%,VT处理减排率为45.42%。相较于CH4,菌剂对N2O的减排效果更好,可达35.32%～61.86%。结合堆肥过程的温度及各腐熟度指标,该研究选取的微生物菌剂能够在保证堆肥效率和产品质量的前提下有效减少温室气体排放。     

Changes in Thermophilic Bacteria Population and Diversity during Composting of Coal Fly Ash and Sewage Sludge

The thermophilic bacteria in compost made from coal flyash-amended sewage sludge were isolated and identified using theBiolog system to investigate the effect of coal fly ash on thethermophilic decomposition of sewage sludge during composting. Atotal of 8 species of Bacillus were isolated from thecompost and Bacillus brevis was the dominant speciesduring the entire composting process. The present resultsdemonstrate that the Biolog system is a fast and simple methodfor identifying bacterial species in compost, provided thatoptimum conditions could be achieved for the Bacillusculture. Adding coal fly ash as an amendment did not change thedominant bacteria species during composting, but decreased thepopulation and diversity of thermophilic bacteria species due tothe high alkalinity and salinity. Fewer thermophilic bacteriawere detected in ash-amended sewage sludge compost than insludge compost. There was also reduced metabolic activityobserved in the ash-amended sludge compost from the data ofCO₂ evolution and weight loss. Although ash amendmentdemonstrated a negative effect on the population and diversityduring thermophilic phase, it did not cause any significanteffect on compost maturity.