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1.
The occurrence of bovine spongiform encephalopathy (BSE) in Canada has resulted in the implementation of regulations to remove specified risk material (SRM) from the food chain. SRM includes the distal ileum of all cattle, and the skull, brain, trigeminal ganglia, eyes, palatine tonsils, and spinal cord and dorsal root ganglia of cattle ≥30 months of age. Composting may be a viable alternative to rendering for SRM disposal. In our study, two bulking agents, barley straw and wood shavings, were composted with beef manure along with SRM in passively aerated, laboratory-scale composters. Both composts heated rapidly, exceeding 55°C after 3 days with oxygen declining in the early composting stage with wood-shaving compost, but returning to near-original levels after 5 days. During composting the two matrices differed (P <0.05) only in water content, TC and bulk density. In the final compost, water content, TC and C/N ratio were higher (P < 0.05), while EC was lower (P < 0.05) in the wood shavings as compared to the straw compost. Approximately 50% of SRM was decomposed after 15 days of composting, with 30% of SRM being decomposed within the first 5 days. Phospholipid fatty acid (PLFA) profiles were used to characterize the microbial communities and showed that Gram positive bacteria were predominant in compost at day 5, a point that coincided with a rapid increase in temperature. Gram negative bacteria and anaerobes declined at day 5 but populations recovered by day 15. Fungi appeared to be suppressed as temperatures exceeded 55°C and did not appear to recover over the remainder of the composting period, with the exception of the straw compost at day 15. On day 5, Actinomycetes increased in the straw compost, but declined in the wood shavings compost, with this group increasing in both types of compost at day 15. Although temporal changes were evident, compost matrices or depth within the composter did not obviously influence microbial communities. Decomposition of SRM also did not differ between compost matrices or with depth in the composters. These results suggest that SRM decompose rapidly during composting and that both mesophilic and thermophilic microbial communities play a role in its decomposition.  相似文献   

2.
添加菌糠对鸡粪-烟末堆肥腐熟度及污染气体排放的影响   总被引：1，自引：0，他引：1  
为探索鸡粪-烟末混合堆肥体系合适的菌糠投入量,减轻堆肥过程中污染气体的排放,通过35 d的堆肥试验,设置3个菌糠投入量[0(CK)、5%、10%],研究鸡粪-烟末堆肥条件下添加菌糠对堆肥腐熟度和污染气体排放的影响。结果表明,堆肥处理堆体温度均能在55℃持续8 d以上,达无害化标准。与CK相比,添加5%、10%菌糠处理堆肥产品对作物生长无毒害作用,腐熟度得到有效改善,但均未达到腐熟标准;添加5%菌糠处理总有机碳(TOC)损失降低了2.39个百分点,总氮(TN)损失降低了8.92个百分点;添加10%菌糠处理TOC损失增加了0.27个百分点,但TN损失降低了11.89个百分点。综合考虑堆肥腐熟度、碳氮损失和环境效应,添加菌糠作为膨松剂能够提升堆肥腐熟度并减少污染气体排放,更有利于农业废弃物肥料化的可持续发展。  相似文献   

3.
The release of ammonia nitrogen during composting of sewage sludge mixed with a lignocellulosic bulking agent leads to a reduction in the agronomic value of the final compost and to harmful effects on the environment. We propose adding a cheap salt FeCl3 which can be used without special precaution to reduce ammonia losses by decreasing pH conditions. An in-vessel co-composting experiment was conducted in a large reactor (100 L) in which FeCl3 was added to sludge mixed with a bulking agent (pine shavings and sawdust) and compared with a control mixture without FeCl3. Temperature, oxygen consumption and pH were monitored throughout the composting of both mixtures. The final balance of organic matter, organic and inorganic nitrogen permitted to conclude that the addition of FeCl3 reduced nitrogen loss (by a factor of 2.4 in relation to the control) and increased mineralisation of the organic nitrogen by 1.6.  相似文献   

4.
不同调理剂对猪粪好氧堆肥效果的影响   总被引：3，自引：1，他引：3  
分别以木屑、药渣、菇渣、砻糠灰作为猪粪堆肥的调理剂,研究其在堆肥过程中温度、含水率、pH、EC和主要营养元素N、P、K的动态变化。结果表明,在整个堆制过程中,4个处理的堆温变化明显呈现出升温期、高温期和降温期3个阶段,其中,木屑处理堆体升温最快,且高温持续时间最长,砻糠灰处理高温持续时间最短;与初始值相比,堆肥后每个处理pH均有所上升,其中菇渣处理上升幅度最大,达0.9个单位;堆制过程中,4个处理有机质总体呈现下降的规律;堆肥后药渣处理的TN和TP含量最高;堆肥后砻糠灰处理的TK含量最高;堆肥后4个处理的pH和EC值都在腐熟堆肥的适宜范围之内,从N+P2O5+K2O总养分和保氮角度来看,应选药渣作调理剂,从提高堆肥TK含量来看,应选砻糠灰作调理剂。  相似文献   

5.
There is an increased interest in composting manure on small horse farms (1-5 horses). It is known that simple backyard, food waste composters do not efficiently reduce pathogens due to their small scale. However, it was not clear if small-scale manure composting on horse farms could ensure pathogen reduction during all seasons. Furthermore, because of potential human health concerns, the release of Aspergillus fumigatus on small horse farms was of interest. The objective of this study was to evaluate pathogen reduction in a simple shed composter and the release of Aspergillus fumigatus emissions from fall to spring under typical farm operational conditions. Horse manure mixed with wood shavings (bedding) was composted for 4-8 weeks in the fall, winter, early spring and late spring. Fecal streptococci and eggs of strongyles, which are a major recognized health concern for horses, were used as pathogen indicator organisms. Temperatures increased in all composting piles during all seasons, but tended to be higher in warmer weather. After 4 weeks, the fecal streptococci reduction was about 10- to 100-fold and, after 8 weeks, about 100- to 1000-fold. There was some effect of season on fecal streptococci levels, with the higher composting temperatures appearing to provide greater reductions. Strongyle eggs in this study were very low and were reduced over time. Levels of viable A. fumigatus spores during turning ranged from 12-2084 CFU m?3, while background levels ranged between 6 - 300 CFU m?3. Overall, this study indicates that composting horse manure mixed with wood shavings reduces pathogens. A. fumigatus levels are elevated during turning, but the levels are lower than those found at sewage sludge/municipal solid waste composting facilities or inside barns.  相似文献   

6.
Composting experiments of fish processing wastes and wood by-products were conducted in the Andean-Patagonian Region. Fish wastes were mixed with sawdust + wood shavings (3:1 ratio by weight) with two replicates. Materials were mixed and placed in 220-liter PVC reactors. After 20 days, materials were remixed and reloaded in the reactors. Samples were taken at 20, 30, 40, 60, 80 and 100 day intervals and chemical analyses were made to assess predictors of compost stability. Thermophilic temperatures over 55°C were sustained long enough to satisfy the EPA requirements for pathogen reduction (72 hours). The decrease of NH4+-N, water soluble carbon and the ratio of water soluble carbon to total nitrogen appeared to be the best parameters for predicting compost stability. Mature compost (CMP) and an organic commercial product, Lombriquen (LQN) were incubated with an Andisol and a Xeric Mollisol at a rate of lOg/kg for 16 weeks (20 to 30 percent soil moisture, 25°C) in order to estimate nitrogen and phosphorus release. Soils amended with LQN retained more P than CMP-amended soils (80 percent vs 60 percent of added Olsen-P in the Andisol and 50 vs 35 percent in the Xeric Mollisol). While N mineralization rates of LQN were variable (three to 11 percent of added total N), CMP showed constant rates for both types of soils (12 percent) and released more available N than LQN.  相似文献   

7.
ABSTRACT

Most composters in the United States use open-windrows. During high intensity precipitation events, uncontained water running off of the surface of the compost piles can potentially contaminate surface waters with nutrients and metals. Water that is absorbed poses no runoff concern but may threaten groundwater quality. To gain insight into these processes, stormwater runoff fractions and water holding capacity of compost piles have been characterized for greenwaste (GW) and biosolids (BS) materials. Laboratory scale experiments were conducted using days 1, 7, and 14 materials representing three different stages of composting. This study also evaluated sloped and flat-top as different pile geometries and surfactant use for promoting infiltration. Results indicate that fresh materials were most hydrophobic and the infiltration rates increased with increased composting times. The water storage capacity of the compost pile increased with the age of the compost pile. Compost water storage capacities could not be reliably estimated as the difference between field capacity and as-received water contents.  相似文献   

8.
Use of composting technology as a treatment/disposal method for food residuals has been investigated by numerous researchers. This project evaluated the applicability of in-vessel, mechanical, rotating drum composting for food residuals. Three batches of food residuals (plate scrapings) were collected from a Texas prison and mixed with fine-textured soft-wood shavings at 2/1, 3/1 and 4/1 (ratios of shavings to food residual on a volumetric basis) to produce 0.4 m3 of compost blend. Temperature, oxygen, pH, bulk density and porosity were tracked throughout a fifteen-day composting trial. Volume and weight reductions were noticed for all blends. All blends reached thermophilic temperatures (> 45°C) while remaining aerobic during the trials. Initial pH was low in all blends, occasionally reaching 3.55 before returning to optimal levels (6.0 to 7.5) for composting. Temperature increases into the thermophilic range during composting corresponded to increases in compost pH. Most nutrients (P, K, Ca, Mg, S, Na and Zn) increased in concentration during the composting period, with the exception of N, which in some instances decreased over time. Composts utilizing the 3/1 ratio of bulking agent/food residual achieved thermophilic temperatures quickest and maintained temperatures longer than did other blending ratios. From this study, it appears that use of the mechanical, in-vessel, rotating drum composter may be a viable alternative for food residual disposal.  相似文献   

9.
Biosolids compost is a good organic amendment but immature compost can exhibit phytotoxic behavior which can be attributed to different toxic substances. Our objective was to determine the phytotoxicity of: i) Biosolids; ii) Mix of biosolids and wood sawdust sampled a day after composting started; iii) The same material sampled at the end of the thermophilic stage; iv) cured compost; v) cow manure and vi) horse manure A germination bioassay was carried out using Lolium perenne (ryegrass) seeds: germination and root growth percentage were determined as well as electrical conductivity, pH, phenol content and volatile organic acids. In three treatments, Ni, Pb, Zn, Cu and Cd were also determined. Ammonia volatilization was determined during biosolids composting. The germination percentage varied from 67% to 95% but the inhibition of root growth appears to be a more sensitive phytotoxicity indicator (18% to 74%. Phytotoxic effects on germinating ryegrass were mainly related to extract pH and electrical conductivity. Potentially toxic elements, volatile organic acids, phenolic compounds and ammonia were not related to germination.  相似文献   

10.
Disposal of crawfish processing residuals (hereinafter, referred to as crawfish residuals) poses a challenging problem to the rapidly expanding crawfish industry. Cocomposting is examined as a waste management alternative to landfill disposal. Four agricultural processing by-products were evaluated for use as bulking agents in composting crawfish residuals: wood chips, rice hulls, bagasse, and bark. Approximately 5 to 6.5 volumes of each bulking agents were mixed with one volume of crawfish residuals in 0.3-m3 composting reactors. Compost temperature was continuously monitored, and moisture content was maintained within a desirable range. Samples were collected twice weekly throughout the 50-d composting process. Use of bagasse as a bulking agent led to the largest reduction in volatile solids (27.6 percent), organic C (55.3 percent), particle size (64.7 percent), and compost volume (52.8 percent). Finished compost using bagasse contained the greatest concentration of N (18.4 g N/kg and 160 mg NH4-N/kg). Self-heating patterns and decomposition of crawfish residuals were satisfactory using all four bulking agents, and no odor, insect or other nuisance problems were detected. The finished products of all compost mixtures were suitable for use as mulch or reuse as bulking agents.  相似文献   

11.
Alternate technologies of compost manufactured from poultry litter (manure) were studied as a means of producing a value-added product for the landscape and nursery industry. Static pile and turned windrow technologies were investigated on a commercial scale with the composting of nearly 300 tons of material. The major difference between the technologies is the amount of energy and labor required. Static pile systems require less energy but more time than windrow turned systems. There was no process advantage found for passively aerated static piles over static piles but costs of passive aeration for pipes and labor were higher than for static piles. Machine turned windrows completed active temperature production within 100 days while portions of both the static and passively aerated piles continued to actively compost past 300 days. Process operational costs and compost quality were similar among the compost methods studied. Production operational cost is driven by the cost of compost ingredients and accounted for 60 to 70% of the cost in the pilot study. Ingredients were poultry litter, wood chips and sawdust. Screened compost was produced at an operational cost of $30 while unscreened compost could be produced for $20 per ton of compost. A production scheme where poultry litter is static pile composted on farms for later transport to regional processing centers appears feasible. This two-part composting procedure will eliminate the transport of raw litter and improve poultry biosecurity. Most likely, a private compost business would provide the expertise, on-farm compost procedures and operate the regional facility.  相似文献   

12.
Field trials demonstrated that agricultural wastes could be successfully composted in the winter with the passively aerated windrow system. Three small windrows were constructed. One pile contained a sheep manure-straw mixture, while the other two piles contained varied amounts of horse manure, cow manure, and bedding materials (straw, wood chips). The piles were constructed on a porous base of wood chips. Standard four-inch (10 cm) perforated pipes were placed approximately three feet apart in the porous base, perpendicular to the length of the windrow. Piles were covered with 15 to 20 centimeters of finished compost. A commercial compost covering fabric permeable to gases and water vapor but impermeable to liquid water was used for additional insulation and protection against high winds. Ambient temperatures ranged from ?27°C to 15°C during the trials. Initially, all three piles froze. Then the ends of the piles began to heat up, with the southern ends which received the most sunlight heating up first. Plugging the pipes seemed to help the piles heat up faster, but did not appear to be necessary. Thermophilic temperatures were attained and the composting cycle took 50 to 80 days after the piles heated up. Oxygen levels were highest at the bottom of the pile, and decreased as one moved to the top of the pile. The biggest practical problem encountered was the snow drifts that periodically formed at the windrow base, covering the pipe openings.  相似文献   

13.
Licorice (Glycyrrhiza glabra L.) is a leguminous herbaceous perennial. Its root extracts are commonly used for medicinal uses and as a flavoring agent in the food and tobacco industries. After extraction, about 10,000 tones of licorice root residues are accumulated in Israel annually with no recycling outlet. The objectives of the current research were to develop a reliable protocol for licorice root wastes composting, to test the use of licorice compost as a peat substitute in growing media and to study its suppressiveness against Fusarium oxysporum f. sp. melonis (FOM) – the causal agent of Fusarium wilt of melon (Cucumis melo L.). Licorice root wastes were cocomposted using temperature controlled forced aeration with the coarse fraction of separated cow manure, in order to enrich both its nutrients content and microbial population. Thermophilic conditions prevailed in the pile for 90 days and the compost stabilized and reached ambient temperature 110 days from start. The physical characteristics of the resulted compost were comparable to that of peat. Nutrient content was high and salinity was relatively low. No phytotoxicity was found in the compost extract, based on the cress germination test. Tomato plants grown in compost showed enhanced development as compared to peat. The number of surviving FOM spores incubated in the compost declined faster then in peat. Fusarium infested melon plants survived much better if planted in the licorice compost, as compared to peat. It is concluded that licorice compost can serve as a peat substitute with preferable qualities.  相似文献   

14.
The effects of seven manufactured commercially available activators were evaluated for their efficiency in the composting of yard trimmings (grass clippings/wood chip mixture). Two naturally available additives, and a control (absence of activator) were also evaluated. Four measures of composting efficiency were used to compare the overall decomposition response for each activator: weight loss, volume reduction, volatile solids decrease, and oxygen uptake rate. Four experimental blocks were set up in the field, and two experimental blocks were set up in the laboratory. The physical/chemical characteristics of the compost material were monitored as a function of time for each additive. Interrelationships between measures of composting efficiency were also evaluated. Results showed that grass clippings can be composted as efficiently with naturally available materials such as topsoil or mature compost, as with commercially available compost activators, or an unactivated control. The cost of commercially available activators was $1.37 to $9.36 per cubic yard of compostable grass clippings. Naturally available materials such as topsoil and mature compost are available in needed quantities at no cost to backyard composters.  相似文献   

15.
Four bulking agents, pine shavings, mixed (long and chopped) grass hay, chopped grass hay and long (whole) wheat straw, were each mixed with pig slurry and tap water to obtain three moisture contents (MC) of 60, 65 and 70%. Quadruplets of each treatment were placed in laboratory composting vessels with a capacity of 105 l and a composting depth of 0·95 m. Using the air plenum at the bottom of each vessel, air was forced at apparent velocities of 0–0·002 m s−1 through each compost mass to measure the air static pressure drop across the compost mass as a function of apparent air velocity. Airflow resistance values were measured for compost depths ranging from 0·55 to 0·85 m. Following this test, all mixtures were aerated for 21 days of composting without overturning. The static pressure measurement procedure was then repeated on all quadruplet mixtures.The air static pressure drop was found with respect to a packed bed under laminar flow, defined using the particle size distribution, porosity, depth and airflow channel characteristics of the compost material. Although MC affected the value of the airflow channel characteristics of the compost material, both the hay and straw demonstrated similar values, while shavings demonstrated values more variable and wider values for MC between 60 and 70%.There was a significant increase in airflow resistance after 21 days of composting, which supports the need for compost overturning to reestablish the material's structure and to restore the airflow channels or pores.  相似文献   

16.
The composting of food waste coupled with urban agriculture presents an opportunity to increase nutrient recycling in urban ecosystems. One potential constraint limiting the expansion of aerobic food waste composting is the availability of carbon-rich recalcitrant materials, such as wood chips. We measured the differences in nutrient retention throughout the compost life cycle for different mixtures of barley mash to wood chips, to assess whether composting using proportionally less wood chips would lead to higher nutrient recycling rates. Nine compost piles (1 m3) were constructed at varying ratios barley mash to wood chips, ranging from 10:90 to 90:10. During the composting process, the 50:50 mixture maintained internal temperatures above 55°C for 30 days, with drop-offs as mixtures diverged in either direction. Food waste content was positively related to internal moisture and CO2, and negatively related to internal O2, throughout the ensuing 3 months. The finished compost was used in raised-bed garden plots during the following summer. Yields of arugula and tomatoes increased with compost barley mash content, saturating at high levels. Across all treatments, <5% of N and <2% of P were recycled from barley mash into new vegetable production. Although the maximum amount of nutrients was recycled using high barley mash compost, these treatments also had lower nutrient recycling efficiency compared to intermediate mixtures. These results indicate that the use of wood chips in composting increases the efficiency nutrient retention from food waste and in turn enhances nutrient recycling in urban environments.  相似文献   

17.
This work is aimed at characterizing compost maturity and, organic matter transformation during this process, by the use of nondestructive spectroscopic and thermal techniques, together with some chemical analysis. Composting was conducted in a laboratory over a period of one year using the organic fraction of domestic wastes, fresh farmyard manure, spent coffee and sawdust as the raw materials. Samples were retired after different periods of composting and were analyzed by differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy as well as by routine chemical parameters including temperature, pH, C/N, ash content and humic-like substances content. Results showed that in case of domestic wastes, spent coffee and farmyard manure, the C/N ratios, ash and humic acid content showed a typical high rate of change during the first 197 days of composting and tended to stabilize thereafter, probably as a result of the maturity of the produced composts. In contrast, sawdust underwent only a very limited transformation even after one year of composting. Thermoanalytical and spectroscopic data confirms these finding and gives useful and complementary information with respect to the structure, the heterogeneity and the relative stability of the compost products. In particular, as the decomposition proceeded, there was an increase in aromatic to aliphatic structure ratio and a decrease in the importance of peptide structures of composts. Besides, both the spectroscopic and the thermal behavior of compost samples, retired beyond 197 days of composting, tended to be regular, less dependent on the raw material and close to that characterizing mature composts, with the exception of sawdust samples. We concluded that the spectroscopic and thermal techniques used are complementary to one another and to chemical tests and could be a powerful and fast approach for the study of compost maturity.  相似文献   

18.
针对当前猪粪好氧堆肥过程中存在的腐熟度低、氮素损失严重、污染气体排放量大等问题,该研究以木本泥炭作为添加剂与猪粪进行联合堆肥,研究了不同木本泥炭添加量(添加比例依次为占物料湿基质量的5%、10%、15%和20%的4个处理)对猪粪好氧堆肥产品腐熟度和堆肥过程中CH4、NH3和H2S等污染气体排放变化的影响。结果表明:在猪粪堆肥中添加木本泥炭作为调理材料,堆体可成功启动升温,在第2~4天堆体可进入高温期,并持续7 d以上,达到无害化卫生标准;经28 d好氧堆肥以后,堆肥产品p H值为8.0左右,电导率值为1.47~1.82 m S/cm,发芽指数均大于80%,达到腐熟标准;木本泥炭添加量增加至15%以上时,有机质分解程度高,物料干质量降解率达22%左右,28 d堆体含水率下降35%左右,CH4、NH3和H2S排放量分别减少82.12%~89.48%、53.47%~63.31%、50.98%~62.76%,总温室气体排放当量减少70.34%~83.26%,堆体总氮损失减少率达44%~63%,保氮效果显著。因此,建议木本泥炭用作猪粪堆肥添加剂的最优添加量为15%~20%(以物料总湿重计)。  相似文献   

19.
The changes in population size of different microbial groups (total aerobic heterotrophs, actinomycetes, fungi, fecal coliforms, ammonium- and nitrite-oxidizing bacteria, and denitrifying bacteria) and the activities of 19 different enzymes (three phosphatases, three esterases, two proteases, three amino-peptidases, and eight glycosyl-hydrolases) were examined during cocomposting of poultry litter (a mixture of poultry manure, waste feed, feathers, and wood shavings) and yard trimmings (a mixture of grass clippings, leaves, and wood barks). Three piles with forced aeration were established by mixing 2:1 (v/v) ratio of poultry litter and yard trimmings. During composting, samples were taken at three different locations (top, middle, and bottom) of the forced aeration piles for microbial and enzyme analyses. Results demonstrated that population size of different microbial groups was not a limiting factor in this composting process as the microorganisms in the poultry litter + yard trimmings compost are in great abundance. Although the numbers of these microbial groups were reduced by high temperature, their populations multiplied rapidly as composting progressed. Fecal coliforms were eliminated by day 49, suggesting that the poultry litter + yard trimmings compost showed an overall increase in diversity and relative abundance of extracellular enzymes present as composting progressed. The population of fungi and actinomycetes (microorganisms active in degradation of cellulose, hemicellulose, and lignin) were positively correlated with esterase, valine amino-peptidase, α-galactosidase, β-glucosidase, and lipase. Of all 19 enzymes examined, ß-galactosidase (enzyme involved in the hydrolysis of lactose) had the most significant positive correlation with microbial populations, such as total aerobic heterotrophs, ammonium- and nitrite-oxidizing bacteria, denitrifying bacteria, and fecal coliforms. Cystine amino peptidase, chymotrypsin, and trypsin showed no evidence of activity during the entire period of composting. This composting process represented a combined activity of a wide succession of environments in the compost pile as one microbial group/enzyme overlapped the other and each emerged gradually as a result of the continual change in temperature as well as moisture content, O2 and CO2 level, and progressive breakdown of complex compounds to simpler ones.  相似文献   

20.
This study was carried out to investigate the influence of wood chip biofilter properties and the depth of biofilter media, on ammonia emissions during high rate composting of dairy manure mixed with bulking agents. The composting and biofiltration process consisted of two series of tests. Experimental trials lasted three weeks and were composted in a 605 L pilot-scale reactor vessel. Initial conditions of composting and biofiltration process between each of two sets appeared to be similar. The experimental design used replication of three biofilter vessels of wood chips in two series of biofilter medium(total of six tests). The ammonia laden emissions from the composting mixture were passed through biofilter media and collected in the boric acid trap from the compost reactor and biofilter vessels. Temperatures in the compost and biofilter, ammonia emissions, and pressure drop across the biofilter media were monitored throughout all runs. Material masses, moisture contents, pH and various chemical properties were determined for initial and final samples from all runs. Results indicated that ammonia emission was influenced by the depth of biofilter media. Optimum biofilter media depth in a closed wood chip biofilter was 40 cm for the ammonia concentration of allowable condition of less than 50 ppm.  相似文献   

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