Composting of spent pig litter in turned and forced-aerated piles

A study was carried out to compare the compositing efficiency of spent litter (a mixture of partially decomposed pig manure and sawdust) in turned and forced-aerated piles. Duplicate piles were built with manual turning (every 4 days) during composting, and duplicate piles were set up with forced aeration using an air pump. The present study demonstrated that the efficiency of composting in the turned and forced-aerated piles was similar. Spent litter in these piles reached maturity at the same time (60 days). The forced-aerated piles went through similar physical, chemical, and microbial changes with the turned piles during composting. The forced-aerated composting system was also as effective as the turned system in eliminating Salmonella sp. in the spent litter. These results suggest that a forced-aerated composting system could be used as an alternative method in composting spent litter. The similarities in temporal changes in temperature, chemical, and microbiological properties of the forced-aerated piles, compared with the turned piles, indicate that addition of a bulking agent under forced aerated composting of spent litter is not necessary. The partially decomposed sawdust in the spent litter provided enough free air space, allowing the delivery of oxygen for the microorganisms in the spent litter piles.     

微生物调控对牛粪堆肥的生物特性影响

研究了微生物调控对牛粪堆肥生物特性的影响.结果表明:(1)与对照相比,接菌(添加HM菌剂)处理可使牛粪堆肥提前2d进入高温期,高温持续时间延长2d.即接菌处理的堆肥温度在第4天达到50.5℃,并保持50℃以上的温度14 d;而对照在第6天达到50.0℃,并保持50℃以上的温度12 d.(2)2种处理堆肥的pH总体呈先升高后降低的趋势,接菌处理的堆肥pH上升幅度不大,比对照低0.1～0.5个pH单位.(3)接菌处理有利于提高牛粪堆肥的纤维素酶、蔗糖酶、脲酶活性水平和峰值.(4)脲酶活性与其他因素之间呈显著负相关(p＜0.01),而温度、pH、蔗糖酶活性和纤维素酶活性之间呈显著正相关(p＜0.01).     

Effects of composting on phytotoxicity of spent pig-manure sawdust litter

The phytotoxicity of spent pig-manure sawdust litter (spent litter) was evaluated during further composting. Aqueous extracts of the spent litter were prepared by shaking the sample with water (1:10 w/v), and the toxicity of these extracts was determined on relative seed germination, relative root elongation and germination index (GI, a factor of relative seed germination and relative root elongation). The sensitivity of six plant species, namely Brassica parachinensis (Chinese cabbage), Brassica albogalera (Chinese kale), Allium sativum (onion), Cucumis sativus (cucumber), Amaranthus espinosus (Chinese spinach), and Lycopersicon esculentum (tomato) were compared. The effect of different moisture levels during composting on the phytotoxicity of the spent litter was also examined. Phytotoxicity of the spent litter was only evident during the earlier stage of composting (first 14 days) and, that seed germination and root elongation reached 100% (same as the control) towards the end of the composting. The concentrations of the major inhibitors, water-extractable Cu and Zn, and NH4(+)-N of the spent litter, declined during composting, indicating that these inhibitors were gradually eliminated as composting proceeded. Multiple regression analysis showed that the NH4(+)-N content of the spent litter was the most important chemical factor affecting phytotoxicity of the plant species selected for this study. Relative root elongation and GI were more sensitive indicators of phytotoxicity than seed germination. In the present study, the GI's of all plant species were >80% at day 60, indicating that the spent litter had reached its maturation by day 60. The responses of different plant species to the water-extracts of the spent litter were different. Among the six species, Chinese cabbage and Chinese spinach were the most sensitive species, and tomato and cucumber were the least sensitive species to indicate phytotoxicity of the spent litter. Moisture adjustment during the composting process did not affect the results of the phytotoxicity test.     

Fate of nitrogen during composting of chicken litter

Chicken litter (a mixture of chicken manure, wood shavings, waste feed, and feathers) was composted in forced-aeration piles to understand the changes and losses of nitrogen (N) during composting. During the composting process, the chemical [different N fractions, organic matter (OM), organic carbon (C), and C:N ratio], physical, and microbial properties of the chicken litter were examined. Cumulative losses and mass balances of N and organic matter were also quantified to determine actual losses during composting. The changes in total N concentration of the chicken litter piles were essentially equal to those of the organic N. The inorganic N concentrations were low, and that organic N was the major nitrogenous constituent. The ammonium (NH(4)(+))-N concentration decreased dramatically during first 35 days of composting. However, the rapid decrease in NH(4)(+)-N during composting did not coincide with a rapid increase in (NO(3)(-)+NO(2)(-))-N concentration. The concentration of (NO(3)(-)+NO(2)(-))-N was very low (<0.5 g kg(-1)) at day 0, and this level remained unchanged during the first 35 days of composting suggesting that N was lost during composting. Losses of N in this composting process were governed mainly by volatilization of ammonia (NH(3)) as the pile temperatures were high and the pH values were above 7. The narrow C:N ratio (<20:1) have also contributed to losses of N in the chicken litter. The OM and total organic C mass decreased with composting time. About 42 kg of the organic C was converted to CO(2). On the other hand, 18 kg was lost during composting. This loss was more than half (59%) of the initial N mass of the piles. Such a finding demonstrates that composting reduced the value of the chicken litter as N fertilizer. However, the composted chicken contained a more humified (stabilized) OM compared with the uncomposted chicken litter, which would enhance its value as a soil conditioner.     

Effects of bacterial inoculum and moisture adjustment on composting of pig manure

Spent litter (a mixture of partially composted pig manure and sawdust) was taken from pig pens employing the pig-on-litter system with and without the addition of a commercial bacterial product (Odor control (OC)-organic fertilizers (OF)). A duplicate series of windrows was set up with spent litter which contained the bacterial product and a further duplicate series was set up with spent litter which did not contain the bacterial product. All four sets had their initial moisture content adjusted to 60% but one of each duplicate pair had its moisture content adjusted to 60% during the entire period of further composting in windrows. The rate of further (windrow) composting was significantly different in the litter which contained no bacterial product and which only had its moisture content adjusted at the beginning of the experiment. Decomposition was incomplete in this set even after day 91. In the three other sets, the rate of decomposition was faster and the spent litter became stabilised by day 56. This result suggests that if the bacterial product has been added during the initial pig-on-litter composting process, moisture adjustment during further (windrow) composting is not important. Conversely, if moisture was adjusted during further composting, the addition of bacterial product during initial pig-on-litter composting would be of no value. Such a finding is of remarkable significance in the further composting of spent litter since this indicates that the process could be run on a much more economical basis.     

The evaluation of stability and maturity during the composting of cattle manure

We examined chemical, microbiological and biochemical parameters in order to assess their effectiveness as stability and maturity indicators during the composting process of cattle manure. The composting material obtained after 15 d in trenches and at different times during the maturation phase (i.e. 80, 180 and 270 d) were analyzed. We found that the material collected at the end of the active phase was inadequate to be applied to soil as organic amendment due to its high content of NH4+, its high level of phytotoxicity and the low degree of organic matter stability. After a maturation period of 80 d, the stability of the sample increased. This was shown by a reduction in the dissolved organic carbon (DOC) content and NH4+ concentration and also by a reduction in the microbial activity and biomass; however, 180 d of composting were not sufficient to reduce the phytotoxicity to levels consistent for a safe soil application. Among the various parameters studied, the change in DOC with composting time gave a good indication of stability.     

Oxidative biodegradation of dissolved organic matter during composting

Dissolved organic matter (DOM) plays an important role in the microbial degradation of compost since it represents the most active organic fraction, both biologically and chemically. The detailed evaluation of the changes in the chemical and biochemical characteristics of DOM induced by oxidative biodegradation, presented in this work highlights the mechanisms involved in the degradation of soluble organic matter during composting. In fact, the results show that during the initial stages of composting, DOM is highly degradable under aerobic conditions, particularly due to the predominance of labile, hydrophilic compounds such as carbohydrates, amino acids and proteins. As such compounds are degraded more resistant aromatic moieties accumulate in solution resulting in a reduction in the degradability of DOM with composting time. This decrease in degradability was found to be highly correlated with microbial oxygen demand, and could have important implications in the evaluation of the composting process.     

Insight into the dynamic microbial community and core bacteria in composting from different sources by advanced bioinformatics methods

Microbial communities are important for high composting efficiency and good quality composts. This study was conducted to compare the changes of physicochemical and bacterial characteristics in composting from different raw materials, including chicken manure (CM), duck manure (DM), sheep manure (SM), food waste (FW), and vegetable waste (VW). The role and interactions of core bacteria and their contribution to maturity in diverse composts were analyzed by advanced bioinformatics methods combined sequencing with co-occurrence network and structural equation modeling (SEM). Results indicated that there were obviously different bacterial composition and diversity in composting from diverse sources. FW had a low pH and different physiochemical characteristics compared to other composts but they all achieved similar maturity products. Redundancy analysis suggested total organic carbon, phosphorus, and temperature governed the composition of microbial species but key factors were different in diverse composts. Network analysis showed completely different interactions of core bacterial community from diverse composts but Thermobifida was the ubiquitous core bacteria in composting bacterial network. Sphaerobacter and Lactobacillus as core genus were presented in the starting mesophilic and thermophilic phases of composting from manure (CM, DM, SM) and municipal solid waste (FW, VW), respectively. SEM indicated core bacteria had the positive, direct, and the biggest (>?80%) effects on composting maturity. Therefore, this study presents theoretical basis to identify and enhance the core bacteria for improving full-scale composting efficiency facing more and more organic wastes.

     

二丁与连翘药渣联合堆肥腐熟度评价

为了对不同比例的二丁与连翘药渣堆肥腐熟度进行评价,采用条垛式好氧堆肥方式,将二丁和连翘两种药渣按照5种不同的比例进行堆肥处理,通过分析堆肥过程中温度、pH、C/N和发芽指数等指标的变化规律,对堆肥腐熟度进行评价。结果表明:在试验处理条件下及堆肥周期内,单一药渣堆肥的两组处理未能完全腐熟,混合药渣堆肥的3组处理均已达到完全腐熟的标准,说明两种药渣混合后进行堆肥,可以有效促进堆肥的顺利进行,且二丁与连翘比例为2∶1(质量比)时发酵效果最好。3组混合药渣的发酵产物可以作为有机肥或土壤改良剂施用,也可以与化肥配合,制备成有机/无机配方肥。     

二丁与连翘药渣联合堆肥腐熟度评价

为了对不同比例的二丁与连翘药渣堆肥腐熟度进行评价,采用条垛式好氧堆肥方式,将二丁和连翘两种药渣按照5种不同的比例进行堆肥处理,通过分析堆肥过程中温度、pH、C/N和发芽指数等指标的变化规律,对堆肥腐熟度进行评价。结果表明:在试验处理条件下及堆肥周期内,单一药渣堆肥的两组处理未能完全腐熟,混合药渣堆肥的3组处理均已达到完全腐熟的标准,说明两种药渣混合后进行堆肥,可以有效促进堆肥的顺利进行,且二丁与连翘比例为2∶1(质量比)时发酵效果最好。3组混合药渣的发酵产物可以作为有机肥或土壤改良剂施用,也可以与化肥配合,制备成有机/无机配方肥。     

Seasonal variability of antioxidant biomarkers and energy reserves in the freshwater gammarid Gammarus roeseli

In gammarids, behavioural and biochemical biomarkers are commonly used in ecotoxicological studies. In our study, we have investigated seasonal variations of several biochemical biomarkers in Gammarus roeseli, a freshwater species. Organisms were sampled monthly over a 1-year period. Gender was distinguished to measure antioxidant enzyme activities like total glutathione peroxidase (GPxtot), selenium-dependent glutathione peroxidase (SeGPx) and catalase enzymes, lipoperoxidation end-product (malondialdehyde, MDA), and energy reserves with protein and lipid contents. In the same time, usual water physico-chemical parameters were measured at the sampling site. A based-gender difference was observed for parameters related to oxidative stress. Females showed higher antioxidant enzyme activities and lower MDA level than males. Parameters related to oxidative stress and energy reserves appeared correlated with temperature and physiological status of organisms. Females GPx activities were lower in autumn and winter when no breeding occurred. In both gender, MDA levels were correlated with temperature with an increase of lipoperoxidation in summer. Lipid contents were the lowest in summer and the highest in winter, probably due to the reproductive status of organisms and their feeding behaviour. Gender-based differences of biochemical parameters suggest a specific sensitivity of males and females in ecotoxicological experiments. Moreover, organisms could be more vulnerable in summer when MDA levels are high and energy reserves low. Deleterious effect of xenobiotics would be different with gender and season.     

RAPD marker and substrate utilization pattern applied to study microbial community diversity in the soil affected by agricultural chemicals

Present analyses of random amplified polymorphic DNA (RAPD) and Biolog GN substrate utilization pattern are combined to further study the diversity of microbial communities in four soils affected by agricultural chemicals. The results showed that the four soil microbial communities were apparently distinguishable in the diversity at RAPD level in terms of the richness and modified richness in the summer, which supports our previous report using the same soils in winter. A significant difference for the average well color development (AWCD) at 72 h incubation was found among the soils in winter using Biolog GN substrate utilization pattern, but this difference was not found among the soils in summer. However, Shannon-Weaver indices for microbial communities in the summer soils polluted by agricultural chemicals were significantly higher than those in winter at metabolic level; in contrast, no significant difference existed between the two seasons for microbial communities in the soil without chemical pollution. Present results suggest that the combined approach using RAPD and substrate utilization pattern could be used to effectively quantify microbial community diversity and its changes among the seasons in the soils affected by agricultural chemicals, simultaneously at molecular and physiological levels.     

接种外源微生物菌剂对香蕉茎秆堆肥的影响

为了研究接种外源微生物菌剂对香蕉茎秆堆肥的影响,本实验采用高温好氧堆肥技术,设计了对照（不接菌）、接种白腐菌及棱盖多孔菌3个处理,探讨了不同处理堆肥过程中堆体温度、水分、pH值、电导率、有机碳、C/N、发芽指数及堆肥质量的变化情况。结果表明,接种微生物菌剂处理的温度均高于对照,且高温期持续时间相对较长,以接种白腐菌处理的高温持续时间最长;接种外源微生物菌剂对堆肥含水率、pH、EC、全碳、C/N变化影响不大;与对照相比,接种白腐菌可增加全氮及全钾的含量,有利于提高堆肥产品质量;接种白腐菌处理在36 d（GI〉50%）就达到腐熟,比对照提前8 d腐熟,明显缩短堆肥腐熟时间;而接种棱盖多孔菌处理比对照推迟10 d腐熟,共需54 d不利于香蕉茎秆堆肥的进行。     

RAPD Marker and Substrate Utilization Pattern Applied to Study Microbial Community Diversity in the Soil Affected by Agricultural Chemicals

Abstract

Present analyses of random amplified polymorphic DNA (RAPD) and Biolog GN substrate utilization pattern are combined to further study the diversity of microbial communities in four soils affected by agricultural chemicals. The results showed that the four soil microbial communities were apparently distinguishable in the diversity at RAPD level in terms of the richness and modified richness in the summer, which supports our previous report using the same soils in winter. A significant difference for the average well color development (AWCD) at 72 h incubation was found among the soils in winter using Biolog GN substrate utilization pattern, but this difference was not found among the soils in summer. However, Shannon-Weaver indices for microbial communities in the summer soils polluted by agricultural chemicals were significantly higher than those in winter at metabolic level; in contrast, no significant difference existed between the two seasons for microbial communities in the soil without chemical pollution. Present results suggest that the combined approach using RAPD and substrate utilization pattern could be used to effectively quantify microbial community diversity and its changes among the seasons in the soils affected by agricultural chemicals, simultaneously at molecular and physiological levels.     

抗生素菌渣堆肥进程中微生物群落的变化

将青霉素菌渣、林可霉素菌渣与牛粪等原料分别进行好氧堆肥实验，以考察堆肥过程中不同菌渣对微生物群落的影响。在堆制的41d里，根据温度变化分阶段采集堆肥样品，采用稀释倒平板法测定细菌、放线菌和真菌的数量。结果表明，菌渣不同，其堆肥中的微生物群落变化趋势不同。青霉素菌渣堆肥中细菌数量变化趋势为高一低，真菌数量变化趋势为高一低．高，放线菌数量为逐渐增加；林可霉素菌渣堆肥过程中细菌数量变化趋势为低一高一低，放线菌和真菌数量变化趋势为高．低．高。依据真菌菌落形态观察，菌渣堆肥中的真菌种类比对照牛粪堆肥单一，表明两种菌渣对堆肥中的微生物多样性均产生了不利影响。林可霉素菌渣堆肥初始时的细菌数量比对照低1个数量级，放线菌数量在整个堆肥进程中都明显低于对照，堆肥结束时，随着菌渣含量的增加，放线菌数量逐渐下降，高温期真菌数量下降幅度随着菌渣含量增加而加大，表明林可霉素菌渣对细菌、放线菌和真菌均有不同程度的抑制。堆肥化后菌渣中林可霉素残留量的减少表明，在一定条件下堆肥处理可以将抗生素菌渣无害化和资源化。     

Microbial abundance and community in subsurface flow constructed wetland microcosms: role of plant presence

In this research, the role of plants in improving microorganism growth conditions in subsurface flow constructed wetland (CW) microcosms was determined. In particular, microbial abundance and community were investigated during summer and winter in Phragmites australis-planted CW microcosms (PA) and unplanted CW microcosms (control, CT). Results revealed that the removal efficiencies of pollutants and microbial community structure varied in winter with variable microbial abundance. During summer, PA comprised more dominant phyla (e.g., Proteobacteria, Actinobacteria, and Bacteroidetes), whereas CT contained more Cyanobacteria and photosynthetic bacteria. During winter, the abundance of Proteobacteria was >40 % in PA but dramatically decreased in CT. Moreover, Cyanobacteria and photosynthetic bacterial dominance in CT decreased. In both seasons, bacteria were more abundant in root surfaces than in sand. Plant presence positively affected microbial abundance and community. The potential removal ability of CT, in which Cyanobacteria and photosynthetic bacteria were abundant during summer, was more significantly affected by temperature reduction than that of PA with plant presence.     

添加小麦秸秆对猪粪高温堆肥腐熟进程的影响

选用猪粪与小麦秸秆为堆肥原料进行高温好氧堆肥实验,研究添加小麦秸秆对猪粪高温好氧堆肥过程中堆体温度、pH值、种子发芽指数、碳氮比和养分等理化指标的影响,寻求猪粪高温堆肥时的最佳秸秆配比,旨在为猪粪快速资源化利用提供科学依据。结果表明,猪粪高温堆肥时添加小麦秸秆可以缩短进入高温发酵阶段的时间,减少氮素损失,加快C/N的降低速率,加速有毒有害物质分解。其中猪粪和小麦秸秆6∶4处理各层温度在2~5 d内上升至50℃,并持续37~46 d,在堆肥结束时,有机质和速效氮含量较堆肥初期下降幅度最小,分别为33.90%和23.76%,全氮、全磷、全钾、速效磷和速效钾含量较堆肥初期提高幅度最大,分别为13.34%、20.24%、53.19%、41.53%和16.57%。若以种子发芽指数80%作为堆肥腐熟的评价指标,猪粪和小麦秸秆6∶4配比堆肥的腐熟速度比纯猪粪快18 d,36 d即可腐熟。综合判断,实际应用中,猪粪与小麦秸秆按体积6∶4进行堆肥较为适宜。     

Microbial activity during composting of anthracene-contaminated soil

Microbial activity of an anthracene-spiked soil mixed with kitchen waste during laboratory composting at 56-59 degrees C was studied using an in-vessel technology. The effect of old compost containing acclimated microorganisms on the composting efficiency was also investigated. Microbial succession, microbial enzyme activity, microbial diversity and anthracene removal rate were analyzed during 42 days of composting. The results demonstrated that inoculating with old compost increased the amounts of thermophilic microorganisms, but did not significantly increase anthracene removal. A microbial succession from mesophilic bacteria to thermophilic bacteria and thermophilic actinomycetes was observed during composting. Polyphenol oxidase activity decreased while catalase activity varied irregularly. Microbial diversity increased drastically when temperature elevated from 35 to 56 degrees C, but decreased when temperature maintained at 56-59 degrees C.     

Effects of different ratios of pig manure to fungus residue on physicochemical parameters during composting

This study examined physicochemical parameters to assess their effectiveness as stability and maturity indicators during the process of composting pig manure and fungus residue at different ratios. The results showed that composting mixtures with all ratios of pig manure to fungus residue maintained a temperature exceeding 50 °C for more than 10 days during composting and met the requirement for pathogen destruction. The treatment containing mainly pig manure showed higher nitrogen loss and a shorter thermophilic phase and maturity time than the treatment containing mainly fungus residue. The germination index (GI) values indicated that compost maturity was achieved in the final compost with initial ratios of pig manure to fungus residue of 9:1–7:3 (GIs of 101.4%, 91.2%, and 81.3%); the ratio of 6:4 did not reach compost maturity (GI of 63.8%) and had an inhibitory effect on seed germination. The results of this study suggest that a ratio of pig manure to fungus residue of approximately 8:2 can be considered suitable for the efficient and quality composting of pig manure and fungus residue.

Implications: Co-composting of pig manure and edible fungi residue with appropriate proportion can effectively reduce the risk of environmental pollution caused by agricultural wastes, as well as achieve a safer and high-quality organic fertilizer, which can be used to improve physical and chemical properties of the soil, increase crop yields, and promote agricultural sustainable development. Therefore, technique of co-composting of pig manure and edible fungi residue has a wide prospect of application in practical production all over the world.     

Development of functional composts using spent coffee grounds,poultry manure and biochar through microbial bioaugmentation

Spent coffee grounds (SCG), poultry manure, and agricultural waste-derived biochar were used to manufacture functional composts through microbial bioaugmentation. The highest yield of tomato stalk-based biochar (40.7%) was obtained at 450°C with a surface area of 2.35 m² g^?1. Four pilot-scale composting reactors were established to perform composting for 45 days. The ratios of NH₄⁺–N/NO₃^?–N, which served as an indicator of compost maturity, indicate rapid, and successful composting via microbial bioaugmentation and biochar amendment. Moreover, germination indices for radish also increased by 14–34% through augmentation and biochar amendment. Microbial diversity was also enhanced in the augmented and biochar-amended composts by 7.1–8.9%, where two species of Sphingobacteriaceae were dominant (29–43%). The scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) were enhanced by 14.1% and 8.6% in the fruits of pepper plants grown in the presence of the TR-2 (augmentation applied only) and TR-3 (both augmentation and biochar amendment applied) composts, respectively. Total phenolic content was also enhanced by 68% in the fruits of the crops grown in TR-3. Moreover, the other compost, TR-L (augmentation applied only), boosted DPPH scavenging activity by 111% in leeks compared with commercial organic fertilizer, while TR-3 increased the phenolic content by 44.8%. Composting facilitated by microbial augmentation and biochar amendment shortened the composting time and enhanced the quality of the functional compost. These results indicate that functional compost has great potential to compete with commercially available organic fertilizers and that the novel composting technology could significantly contribute to the eco-friendly recycling of organic wastes such as spent coffee grounds, poultry manure, and agricultural wastes.