Effect of matured compost as a bulking and inoculating agent on the microbial community and maturity of cattle manure compost

Cattle manure composts were consecutively manufactured. Compost that reached maturity first was used as a bulking and inoculating agent for subsequent compost production. The microbial community was measured through phospholipid fatty acid analysis. Changes in the content of fatty acid methyl esters derived from phospholipids were similar in all the composts. The diversity index for the fatty acid methyl ester content increased in the secondary-produced compost from the onset of composting. Microbial succession was accelerated using matured compost. The proportion of biomarker fatty acids for gram-positive bacteria also increased in the secondary-produced compost from the early stage of composting. Changes in germination index indicated the maturity stage of the compost. The proportion of biomarker fatty acids for gram-positive bacteria was positively correlated to the germination index, indicating that phospholipid fatty acid analysis is an indicator for evaluating the maturity of cattle manure composts.     

Evolution of extracellular enzyme activities during manure composting

AIMS: The objectives of this work were to determine the extracellular enzyme profiles during composting, relate the activities of these enzymes to the changes in microbial population and compare the enzyme profiles between two manures. METHODS AND RESULTS: API ZYM assay was used to monitor the activities of 19 extracellular enzymes during poultry and pig manure composting. Results showed an overall increase in diversity and relative abundance of enzymes present. The relative abundance and activities of enzymes were higher in poultry manure than in pig manure. Among the 19 enzymes tested, esterase, valine amino-peptidase and alpha-galactosidase were the most abundant enzymes in poultry manure, whereas it was N-acetyl-beta-glucosaminidase for the pig manure. A number of these enzymes correlated with change in numbers of different microbial groups during composting. CONCLUSIONS: The composting process represented a combined activity of a wide succession of environments, as one enzyme/microbial group overlapped the other and each emerged gradually due to the continual change in temperature and progressive breakdown of complex compounds to simpler ones. SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented here show the applicability of the API ZYM test not only in monitoring the quantitative and qualitative fluctuation of the available substrate during composting, but also in revealing differences in composts and compost maturity.     

Effects of the maturity of wood waste compost on the structural features of humic acids

An analytical scheme for the separation of humic substances (HSs) and non-humic substances (non-HSs) was established to estimate the humification index (HI), which was defined as the ratio of HS carbon content to non-HS carbon content. The alkaline compost-extract contained a mixture of HSs and non-HSs, while acidification of the compost-extract resulted in precipitation of humic acid (HA). The acidified supernatant contained fulvic acid (FA) and non-HSs. In the present study, DAX-8 resin was used to separate FA and non-HSs. HI values, which were estimated to evaluate the maturity of wood waste compost, increased with composting duration. To determine the effects of compost maturity on HA structural features, correlations between HI and indicators of the degree of HA humification (atomic ratios, acidic functional group contents, spectroscopic parameters and molecular weight) were investigated. HI values were significantly related to the indicators of the extent of HA humification during composting.     

畜禽粪便堆肥的理化腐熟指标及其红外光谱

选择新鲜的牛粪、猪粪和鸡粪为堆肥原料,通过室内模拟直接堆肥试验,研究堆肥过程理化参数变化、种子发芽指数以及腐熟物红外光谱特征.结果表明: 堆肥过程温度变化明显,牛粪出现一次堆肥高温阶段,鸡粪和猪粪各两次,堆肥温度超过50 ℃以上时间均大于10 d,温度可以最直观地表征堆肥的腐熟程度.堆肥过程中pH值变化幅度较大,其中猪粪的pH值从6.63上升至7.74,鸡粪从7.73上升至8.66,牛粪则先从7.86上升至8.36再下降至7.52;有机碳含量逐渐降低,牛粪、猪粪和鸡粪分别下降23.3%、28.2%和31.7%;堆肥过程中,牛粪、猪粪和鸡粪的铵态氮含量分别下降87.8%、73.6%和79.7%,硝态氮含量分别增加至堆肥前的56.81、6.49和4.85倍,铵态氮/硝态氮均下降至2以下.温度、pH值、有机碳含量和铵态氮/硝态氮能较好地反映3种粪便高温堆肥的腐熟程度,且与种子发芽率相关性较高(P≤0.05).红外光谱分析表明,在堆肥过程中,牛粪和猪粪的脂肪族、多糖类物质减少,芳香结构化增强,腐殖化程度增加;鸡粪则相反.在建立理化指标体系的同时,应兼顾物质结构的稳定性.     

Characterization of natural organic matter (NOM) derived from sewage sludge compost. Part 1: chemical and spectroscopic properties

In this study changes in the properties of natural organic matter (NOM) were studied during composting of sewage sludge in a laboratory experiment using the pile method. Typical physicochemical parameters were measured during 53 days of composting including humic fractions. The effects of humification on the molecular properties of humic acids (HA) were investigated by 13C CP/MAS NMR spectroscopy. On the basis of chemical analyses, 53 days of composting sewage sludge with structural material can be divided into three phases: (i) domination of rapid decomposition of non-humic, easily biodegradable organic matter (two to three weeks), (ii) domination of organic matter humification and formation of polycondensed, humic-like substances (the next two weeks), (iii) stabilization of transformed organic material and weak microbial activity. Spectroscopic characterization (13C NMR) of compost humic acids reveals changes in their structures during maturation. The changes are highly correlated with the processes taking place in bulk compost.     

湿度对堆肥理化性质的影响

水分是堆肥微生物生命活动的基础 ,也是堆肥中重要的工艺控制参数。弄清湿度对堆肥微生物及理化性质的影响 ,对于优化堆肥工艺参数、提高堆肥效率、降低投资和运行成本具有重要意义。综述了堆肥湿度研究的动态 ,指出了当前研究中存在的问题 ,并提出了未来的研究方向。大量的研究表明 ,湿度低于 4 5 %或高于 6 5 %都不利于堆肥处理。湿度太高会导致堆料的压实度增加、FAS减少、透气性能降低 ,从而导致堆体内氧气供应不足、堆肥升温困难、有机物降解速率降低、堆肥周期延长。湿度过低 ,水分会限制堆肥微生物的新陈代谢 ,导致微生物活性下降、堆肥腐熟困难。由于鼓风、散热、水蒸发等会使堆体内存在湿度的空间变异 ,也会降低堆肥效率和堆肥产品的质量。另外 ,堆肥湿度还影响堆肥的保肥能力。由各文献得出结论 ,堆肥的最佳湿度范围一般为 5 0 %～ 6 0 %左右     

Development of compost maturity and Actinobacteria populations during full-scale composting of organic household waste

AIMS: This study investigates changes in microbiological and physicochemical parameters during large-scale, thermophilic composting of a single batch of municipal organic waste. The inter-relationships between the microbial biomass and community structure as well as several physicochemical parameters and estimates of maturation were evaluated. METHODS AND RESULTS: Analyses of signature fatty acids with the phospholipid fatty acid and ester-linked methods showed that the total microbial biomass was highest during the early thermophilic phase. The contribution of signature 10Me fatty acids from Actinobacteria indicated a relatively constant proportion around 10% of the microbial community. However, analyses of the Actinobacteria species composition with a PCR-denaturing gradient gel electrophoresis approach targeting 16S rRNA genes demonstrated clear shifts in the community structure. CONCLUSIONS: This study demonstrates that compost quality, particularly maturity, is linked to the composition of the microbial community structure, but further studies in other full-scale systems are needed to validate the generality of these findings. SIGNIFICANCE AND IMPACT OF THE STUDY: The combination of signature lipid and nucleic acid-based analyses greatly expands the specificity and the scope for assessing the microbial community composition in composts. The results presented in this study give new information on how the development of the compost microbial community is connected to curing and maturation in the later stages of composting, and emphasizes the role of Actinobacteria in this respect.     

翻堆频率对堆肥减量化、腐殖化和稳定化的影响

好氧堆肥是有机固体废弃物处理处置的有效手段之一,堆肥还田也是贫瘠土壤改良的常用措施。但好氧堆肥是一个典型的CO_2等温室气体的释放过程。如何减少堆肥过程中的CO_2释放,强化堆肥的腐殖化过程对于实现有机固体废弃物的低碳化堆肥、提高作为优良土壤改良剂的腐殖质产量具有重要意义。本文选取农林秸秆和餐厨垃圾作为堆肥原料,研究不同翻堆频率对堆肥过程中的物料减量化、腐殖化和稳定化的影响,以期发现一个较低碳的堆肥工艺,并从微生物角度初步探索了其影响机制。研究结果显示,不同的翻堆频率(分别为每2 d、4 d和6 d翻堆一次),堆料的减量化和腐殖化程度有一定差异,翻堆频率为4 d的堆肥工艺物料减量率最高为50.5%,但碳减量率最低为77.4%;而翻堆频率为2 d的堆肥工艺腐殖质产量最高;3种堆肥工艺经62 d堆肥都达到了腐熟程度,翻堆频率为4 d的堆肥工艺腐熟化程度最高。不同的翻堆频率可能通过影响堆肥过程中堆料的温度、含氧量等因素从而改变堆料中活性微生物量、种类和生物酶活性,进而影响堆料的矿化和腐殖化进程。     

Study of the composting process of winery and distillery wastes using multivariate techniques

Physico-chemical, chemical and biological parameters were studied throughout the composting process of four winery and distillery composts and the data set of compost characteristics was analysed using multivariate techniques: factorial analysis (FA) and linear discriminant analysis (LDA), in order to classify the different parameters studied and thus, to establish those that better describe the composting process of this type of wastes. Through factorial analysis (FA) of the parameters studied throughout the composting process, four components that explained 85.6% of the variability were established. The parameters associated to compost maturity, agronomic character, water-soluble fraction and ammonia and temperature increment were grouped in the components F1, F2, F3 and F4, respectively, which can reduce the number of determinations needed to ascertain the maturity and quality of the composts. In addition, the linear discriminant analysis on the factorial components makes possible to classify the four composts with a percentage of success around 95%.     

Microbial Properties of Composts That Suppress Damping-Off and Root Rot of Creeping Bentgrass Caused by Pythium graminicola

Composts prepared from a variety of feedstocks were tested for their ability to suppress seedling and root diseases of creeping bentgrass caused by Pythium graminicola. Among the most suppressive materials in laboratory experiments were different batches of a brewery sludge compost and a biosolids compost from Endicott, N.Y. Batches of these composts that were initially not suppressive to Pythium damping-off became more suppressive with increasing compost age. Leaf, yard waste, food, and spent mushroom composts as well as certain biosolids, cow manure, chicken-cow manure, and leaf-chicken manure composts were not suppressive to Pythium damping-off. In some cases, turkey litter, chicken manure, chicken-leaf, and food waste composts were inhibitory to creeping bentgrass seed germination in laboratory experiments. Microbial populations varied among all of the composts tested. Bacterial populations were high in all composts except the turkey litter compost, in which populations were 1,000- to 10,000-fold lower than in the other composts tested. Among the highest populations of heterotrophic fungi and antibiotic-producing actinomycetes were those found in all batches of the brewery sludge compost, whereas the lowest populations were found in turkey litter, chicken manure, and food waste composts. Heat treatment of suppressive composts reduced populations of bacteria, fungi, and actinomycetes in all composts tested. Disease suppressiveness was also reduced or eliminated in heated composts. Amending heated composts with small amounts of nonheated compost restored suppressive properties and partially restored microbial populations to wild-type levels. A strong negative relationship between compost microbial activity (as measured by the hydrolysis of fluorescein diacetate) and Pythium damping-off severity was observed. When composts were applied to creeping bentgrass in field experiments, a significant level of suppressiveness was evident with some composts when disease pressure was high (i.e., disease ratings high in uninoculated plots). A 1991 batch of turkey litter compost and the 1990 batch of Endicott biosolids were consistently suppressive to foliar symptoms of Pythium root rot on creeping bentgrass. This study indicates that suppression of Pythium diseases of creeping bentgrass in batches of brewery sludge and Endicott biosolids composts, and possibly in other suppressive composts examined in less detail in this study, is related directly to the microbial activities in the composts. On the other hand, the mechanisms of Pythium suppression in turkey litter and perhaps other poultry-based composts is not related directly to the compost microbial activity. Although turkey litter showed a lack of suppressiveness in laboratory bioassays and low microbial populations and activity, it resulted in a significant and consistent level of suppressiveness in field experiments. Therefore, the microbiological properties of Pythium-suppressive composts may differ substantially, and measurements of microbial populations and activity may not be predictive of the level of disease suppression in all composts.     

Response of compost maturity and microbial community composition to pentachlorophenol (PCP)-contaminated soil during composting

Two composting piles were prepared by adding to a mixture of rice straw, vegetables and bran: (i) raw soil free from pentachlorophenol (PCP) contamination (pile A) and (ii) PCP-contaminated soil (pile B). It was shown by the results that compost maturity characterized by water soluble carbon (WSC), TOC/TN ratio, germination index (GI) and dehydrogenase activity (DA) was significantly affected by PCP exposure, which resulted in an inferior degree of maturity for pile B. DGGE analysis revealed an inhibited effect of PCP on compost microbial abundance. The bacteria community shifts were mainly consistent with composting factors such as temperature, pH, moisture content and substrates. By contrast, the fungal communities were more sensitive to PCP contamination due to the significant correlation between fungal community shifts and PCP removal. Therefore, the different microbial community compositions for properly evaluating the degree of maturity and PCP contamination were suggested.     

Methodological aspects of microcalorimetry used to assess the dynamics of microbial activity during composting

Isothermal microcalorimetry is a sensitive non-invasive analytical tool that can become useful in research on compost and other biosolids. The aim of the present study was to address several methodological aspects that are critical to the use of microcalorimetry to assess the dynamics of microbial activity in such systems. The results show that: (1) The calorimetric baseline is strongly influenced by the run temperature in the range relevant to composting systems (20–60 °C), and is also affected by addition of the water that is required to maintain or optimize microbial activity, presumably because some water evaporates through ampoule gaskets. (2) Amending mature compost with readily available substrates requires additional careful baseline treatment. (3) Sample heterogeneity can be successfully minimized by passing through a 2-mm sieve. Additional size separation can be useful to enable focusing on the more active fractions. (4) Oxygen depletion is a key feature in batch calorimetric analysis; for samples of highly active composts or manure, the total amount of heat released relative to the oxygen available in the ampoule may indicate the co-existence of anaerobic and aerobic metabolic pathways. Finally, practical recommendations for microcalorimetry analyses of pre-mature and mature composts are outlined.     

Investigating microbial activities in compost using mushroom (Agaricus bisporus) cultivation as an experimental system

Investigations into the dynamic nature of composting environments are necessary to understand and ultimately optimise the complex processes that occur. In this study, various parameters were measured to investigate physical, chemical and biological changes that occur in compost during the production of Agaricus bisporus. In addition to monitoring the compost samples during mushroom cultivation, uninoculated samples were maintained for comparative purposes. Principal components analysis of the variables measured showed a clear distinction between the thermophilic Phase I composts, uninoculated Phase II composts and mushroom inoculated composts. Leucine assimilation, a novel technique to composting environments, is presented as suitable method for assessing microbial activity in such systems. Strict agreement between leucine assimilation and fluorescein diacetate (FDA) hydrolysis, a rarely used technique in composting environments, was not observed, suggesting that neither should be used as a sole measure of microbial activity in compost. Association of FDA hydrolysis with the culturable heterotrophic count suggests that FDA hydrolysis may indicate bacterial as opposed to total microbial activity.     

Suppression of Pythium ultimum by Biowaste Composts in Relation to Compost Microbial Biomass, Activity and Content of Phenolic Compounds

Seventeen composts from separately collected organic household waste plus one bark compost and one compost from grape marc were analysed for suppression of Pythium ultimum, phytotoxicity, microbial biomass and activity, substrate-induced respiration, extractible phenolic compounds and other physical and chemical parameters. Nine of the samples were mildly suppressive to P. ultimum, the others were conducive. The bark compost sample was strongly suppressive. Therefore of the examined composts, only the bark could be used to exert an economically relevant control of P. ultimum in horticultural media. A large part of the compost samples was slightly phytotoxic. Microbial biomass and SIR had only weak correlations with disease incidence. Microbial activity and content of extractible phenolics were positively correlated with disease incidence. None of the tested parameters were therefore suitable as a predictive test for suppression of P. ultimum with the compost samples used in this study.     

Evaluation of maturity and stability parameters of composts prepared from agro-industrial wastes

The objective of this study was to evaluate changes in physical, chemical and biological parameters to assess the maturity and stability of composts prepared from mixture of different farm and agro-industrial wastes over a period of 150 days. All the composts appeared granular, dark grey in color without foul odor and attained an ambient temperature at 120 days of composting indicating the stable nature of composts. Correlation analysis showed that the optimal values of the selected parameters for our experimental conditions are as follows: organic matter loss >42%, C:N ratio <15, water soluble organic carbon (C(w)):organic N (N(org)) ratio <0.55, humic acid (HA):fulvic acid (FA) ratio >1.9, humification index (HI) >30%, cation exchange capacity (CEC):total organic carbon (TOC) ratio >1.7 and germination index (GI) >70%. Compost enriched with sewage sludge, pressmud and poultry waste matured earlier compared to composts either enriched with distillery effluent or un-enriched.     

Aerobic composting of chips from clear-cut trees with various co-materials

Swollen chips made from trees felled during clear-cutting were composted with various organic and inorganic materials in an aerobic composting reactor for 5 months and then piled for 5 months. The organic materials included chicken feces, urea, nitrogenous lime (calcium cyanamide, manure), and material rapidly composted from food garbage in 24-h bacterial fermentation, while the inorganic materials were coal ash and volcanic ash. In this paper, we first attempt to estimate the quality and degree of maturity of each compost from its chemical properties. Furthermore, we try to calculate the maturity of the fermented wood chip composts from their mixture ratio of the initial materials by multiple linear regression analysis. We measured changes in the C/N ratio, nitrate nitrogen (NO3-N) content, percentage of humic acid in the alkali soluble fraction (PQ), cation exchange capacity, pH, and EC during the composting period. The degrees of maturity of the composts were estimated via a plant growth test using Chinese cabbage. We found that the CN ratio, NO3-N concentration, and PQ were suitable for estimating the degree of maturity of wood chip composts. For maturity, the CN ratio should be less than 14, the PQ more than 66.2, and the NO3-N concentration more than 853 mgkg-1. We devised an equation to estimate the degree of maturity after 10 months by a multiple linear regression analysis from the mixing ratio of wood chips and the co-composted materials. From the multiple linear regression analysis, the above three indices of compost maturity could be estimated from the mixing ratio of the initial materials. This equation should enable us to determine the degree of compost maturity after 10 months based on the initial mixing ratio.     

Growth potential of faecal bacteria in simulated psychrophilic/mesophilic zones during composting of organic waste

Aim: This study investigated the growth potential of Salmonella serotype Typhimurium and faecal indicator organisms in compost materials and the correlation between bacterial growth potential and the physico‐chemical composition of the compost substrate and temperature. Methods and Results: Survival of Salm. Typhimurium, Enterococcus spp. and total coliforms at 14, 24 and 37°C was determined in material of different degrees of maturity collected from composting plants for household waste and manure. All three micro‐organisms showed the potential for growth in the material from active composts (Solvita index 4) but inactivation generally occurred over time in mature compost material (Solvita index 7–8). Conclusions: Salm. Typhimurium had the potential for growth in psychrophilic/mesophilic (P/M) zones of immature compost material and its growth potential correlated negatively with the maturity of the compost and the temperature within the simulated P/M zone. Significance and Impact of the Study: The risk of pathogen regrowth in P/M zones during organic waste composting further emphasizes the importance of good management practices and of avoiding P/M zones in combination with low compost maturity.     

Characterization of dairy cattle manure/wallboard paper compost mixture

The aim of this research was to evaluate the use of manufacturing wallboard paper scraps as an alternative bulking agent for dairy cattle manure composting. The characteristics of the composting process were studied based on the changes in physico-chemical parameters and final compost quality. Composting of dairy cattle manure with wallboard paper was performed in a 481-L cylindrical reactor with vacuum-type aeration. Rapid degradation of organic matter was observed during the thermophilic stage of composting due to high microbial activity. High temperature and alkaline pH conditions promoted intense ammonia emission during the early stage of composting. The number of mesophilic and thermophilic microorganisms were found to be affected by changes in temperature at different composting stages. The total nitrogen (N), phosphorus (P), potassium (K), and sodium (Na) concentrations of the mixture did not change significantly after 28days of composting. However, the presence of gypsum in the paper scraps increased the calcium content of the final compost. The wallboard paper had no phyto-inhibitory effects as shown by high germination index of final compost (GI=99%).     

Investigation of the microbial community structure and activity as indicators of compost stability and composting process evolution

In a bid to identify suitable microbial indicators of compost stability, the process evolution during windrow composting of poultry manure (PM), green waste (GW) and biowaste was studied. Treatments were monitored with regard to abiotic factors, respiration activity (determined using the SOUR test) and functional microflora. The composting process went through typical changes in temperature, moisture content and microbial properties, despite the inherent feedstock differences. Nitrobacter and pathogen indicators varied as a monotonous function of processing time. Some microbial groups have shown a potential to serve as fingerprints of the different process stages, but still they should be examined in context with respirometric tests and abiotic parameters. Respiration activity reflected well the process stage, verifying the value of respirometric tests to access compost stability. SOUR values below 1 mg O₂/g VS/h were achieved for the PM and the GW compost.     

Transformation of organic matter during co-composting of pig manure with sawdust

Co-composting of pig manure with sawdust was studied in order to characterize the organic transformation during the process, using both chemical and spectroscopic methods. Humic acids (HA) and fulvic acids (FA) were fractionated from immature and mature pig manure compost, and characterized. After 63 days of composting, the ratio of total organic carbon and soluble organic carbon decreased to a satisfactory low level and the solid and soluble C/N ratios decreased rapidly for the first 35 days before attaining a constant value, indicating compost maturity. Humification could be responsible for the increase in humic acid proportion during composting. The increase in the aromatic bonds after composting, as indicated by the reduction of C/H and C/O ratios of HA and FA, resulted in a more stabilized product. A substantial increase in high molecular weight compounds along with a small increase in low molecular weight compounds was found in mature compost. Moreover the HA also had more complex organic compounds at this stage. Fluorescence spectral analysis showed an increase in the maximum wavelength of HA associated with the contents of aromatic structures in solution. A decrease in relative absorbance of HA at 1160 cm(-1), 2950 cm(-1) and 2850 cm(-1) was seen in the FTIR spectra indicating the decomposition of complex organic constituents, into simpler ones. Increase in the aromatic compounds with higher stability could account for the relative increase in the absorbance of HA at 1650 cm(-1) and 1250 cm(-1) of the mature compost. The composition of FA was not much altered, indicating most of the degradation of organic matter occurred in HA. Data from organic carbon, C/N ratio, elemental analysis, E(4)/E(6) ratio, gel chromatography, fluorescence and FTIR spectra indicated an increase in polycondensed structures and the presence of more stable organic matter in the mature compost.