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1.
Monitoring the physical, chemical and biological properties during accelerated composting enables concise determination of its stability and maturity. Determination of physical parameters such as pH, moisture and temperature, chemical parameters such as total nitrogen (N), phosphorus (P), potassium (K), organic matter and humic acid as well as biological parameters such as microbial count and carbon dioxide (CO2) evolution was carried out during a four (4) week composting period, The trend observed for pH showed the mesophilic and thermophilic phases and a similar trend was observed for the compost temperature. Intermittent increase and decrease was observed for total N, P, K as well as for the fungal and bacterial population. A direct relationship was observed among the bacterial population, CO2 evolution and humic acid. However, composting for four (4) weeks produced a stable compost, which was evident through the physical observation of the final product and the results obtained for the chemical and biological parameters.  相似文献   

2.
Composting of pruning waste, leaves and grass clippings was monitored by different parameters. A windrow composting pile, having the dimensions 2.5 m (height) x 30 m (length) was establish. The maturation of pruning waste compost was accompanied by a decline in NH4 +-N concentration, water soluble C (WSC) and an increase in NO3 –-N content. Both organic matter (OM) content and total N (TN) losses during composting followed a first-order kinetic equation. These results were in agreement with the microbiological activity measured either by the CO2 respiration or dehydrogenase (DH-ase) activity during the process. Statistically significant correlations were found between DH-ase activity, easily biodegradable organic C forms, NH4 +-N and NO3 –-N concentrations and organic matter content and N losses. For this reason, DH-ase activity and the CO2 evolution could be used as good indicators of pruning waste compost maturity. In contrast, humification parameters data from the organic matter fractionation did not agree with the initially expected values and did not contribute to the assessment of compost maturity. Neither the cation exchange capacity nor the germination index showed a clear tendency during the composting time, suggesting that these parameters are not suitable for evaluating the dynamics of the process.  相似文献   

3.
The effect of Bacillus licheniformis HA1 cell density on the acceleration of organic waste composting was tested in a bench-scale composting system utilizing a process limit temperature of 60°C. Variables measured during composting were CO2 evolution rate, conversion of substrate carbon and pH. When an initial cell density of 2.0×104 cfu/g-dry solid was used, the strain HA1 increased in number and prevented the decrease in pH during the early stage of composting. This resulted in enhanced populations of other thermophiles and increased the rate of organic matter decomposition. By contrast, no effect was observed at a lower cell density of HA1. It was found that the minimum cell density of HA1 to accelerate organic decomposition was around 104-105 cfu/g dry solid of raw material.  相似文献   

4.
As interest in food waste composting grows, so does the need for proven composting methods. Stability testing has been proposed as a compost quality assurance tool. We conducted this study to: (i) to evaluate the efficacy of simple outdoor composting methods in producing a compost with a low, stable decomposition rate, and (ii) to determine the reliability of simple, 4-h compost stability evaluation methods. Composting was conducted outdoors in winter and spring in Eugene, Oregon without moisture addition. Mixed food waste was combined with screened dairy solids and ground yard trimmings. Sawdust was used to cover windrows for the first 27 d of composting. Compost windrow temperatures remained above 55°C for 30+ d. Carbon dioxide evolved with several 4-h test methods was strongly correlated (r2 > 0.7) with CO2 evolved using a 48-h test. A limited-turn windrow (LTW) composting system produced compost with slightly greater stability than a passively aerated windrow (PAW) composting system. Food waste compost samples had a low CO2 evolution rate after 71 to 99 d using either composting system. Compost CO2 evolution rate at 25°C decreased with composting time, reaching approximately 1 to 4 mg CO2-C g compost C?1 d?1 for the PAW method and 0.5 to 2 mg CO2-C g compost C?1 d?1 for the LTW method. Putrescible organic matter in food waste was effectively decomposed in outdoor windrows using composting methods that did not employ forced aeration, self-propelled windrow turners, or manufactured composting vessels. Several 4-h stability tests showed promise for implementation as quality assurance tools.  相似文献   

5.
Because of proposed bans on the landfilling and incineration of leaves, grass and brush, large-scale composting is fast becoming the primary disposal option for yard trimmings in many states. Few systematic studies have been done to compare the effects of turning regime, feedstock mix ratio, or windrow vs. pile configuration on composting and the characteristics of finished compost. In this study, various ratios of leaves, grass and brush were mixed and composted in two series of windrows; and one set of static piles. One windrow series (#1) was turned seven times every four weeks, while the other windrow series (#2), and the piles, were turned once every four weeks. The effects of the different treatments were examined by measuring compost temperature, oxygen concentration, pH, organic matter and moisture content, volatile fatty acid content, bulk density, stability, humification and seed germination indices, total and available nutrient levels, and particle size distribution. Results showed that turning frequency had little impact on oxygen concentrations, VFA content and temperatures during the composting of yard trimmings in windrows, however, in piles temperatures were substantially higher and oxygen concentrations fluctuated greatly. The composts from all the treatments were stable, (oxygen uptake rates < 0.1 mg O2/g OM/hr) after 60 days of composting regardless of the turning frequency, mix ratio or configuration. The bulk density inereased much more rapidly in frequently turned windrows than in the other treatments and particle sizes were smaller in these windrows. In most respects however, the final composts (day 136) were remarkably similar and none inhibited Cress seed germination or root elongation. The pH of all the composts, and the soluble salts and nitrate levels in composts made with high levels of grass, exceeded guidelines for greenhouse growth media.  相似文献   

6.
Soil was freed of its organic matter by heating it to 400°C. Plants were grown in a 14CO2 atmosphere and from them a labelled “soil organic matter” (humus) was prepared by composting the plant material for more than 3 yr in the modified soil under laboratory conditions. The influence of small additions of unlabelled glucose on the decomposition of the labelled soil organic matter was studied. Shortly after the addition of glucose there was a small extra evolution of 14CO2, which lasted about 1 day. It is claimed that the extra evolution of 14CO2 was caused by conversion of labelled material in the living biomass and was not due to a real priming action, i.e. an accelerated decomposition of humic substances or dead cellular material.  相似文献   

7.
The hydrolysis of the fluorescein diacetate (FDA), related to several soil hydrolases, has been utilised to estimate the potential microbial activity of soil freshly amended with a wide range of organic amendments and compared to the size and activity of soil microflora, measured by the microbial biomass C (B C) and CO2 evolution, respectively. Three different composting mixtures at different phases of the composting process were added to a semi-arid soil and incubated for 2 months under laboratory conditions. The addition of the organic amendment immediately increased B C and both measures of microbial activity (FDA and CO2 evolution). Highly significant correlations were found between FDA hydrolysis and B C for soil amended with the three composting mixtures (r = 0.81–0.96; P < 0.01), regardless of the origin, composition and degree of stability of the organic amendments. FDA hydrolysis, conversely to CO2 evolution, was unaffected by the disturbance caused by the soil amendment, indicating that the two parameters probably reflect different aspects of soil microbial activity. FDA hydrolysis could serve as an alternative estimation of the microbial biomass in freshly amended soils, despite the disturbance caused by the exogenous organic matter.  相似文献   

8.
A laboratory method was developed to quantify CO2, NH3 and VOC yields and to follow solids decomposition during composting of MSW or its components. All organic substrates were shredded, water and nutrients were added to near optimum levels prior to composting, and composting was continued until feed materials reached approximately the full extent of decomposition. Twenty five L stainless steel digesters were used and aluminum packing was mixed with the wastes to facilitate airflow. Thermophilic temperatures were maintained and air supplied in excess. Nutrients were added to reach an initial C/N ratio of approximately 30. CO2 and NH3 gases in the exit air stream were captured in alkaline and acidic solutions, respectively, and quantified through titration on a cumulative basis. VOC traps, prior to the gas traps, captured emitted volatile organic compounds, which were quantified on a cumulative basis. Solids were analyzed for hot water soluble matter, fats and lipids, cellulose, hemicellulose and lignin/humus. Food wastes, yard wastes and mixed paper produced approximately 368, 220 and 153 g C-CO2/dry kg and approximately 40.5, 4.6 and 2.0 g N NH3/dry kg of starting material, respectively. VOC volatilization profiles had a decreasing trend with composting. Partially composted MSW produced 8.2 mg/dry kg of 8 selected VOCs. CO2, NH3 and VOC recovery tests resulted in efficiencies of 98.6%, 97.6% and 94.6% respectively. Reproducibility of the solids decomposition and gaseous emissions measurements was observed. Carbon and nitrogen mass balance closures ranged from 85.5% to 117.1% and 32.2% to 175% respectively.  相似文献   

9.
The aims of this work were: i) to evaluate, during a composting process, some parameters in two contrasting raw materials: one a ligneous material (C1) and the other (C2) a mixture of horse and poultry manure with a low straw percentage and ii) to compare results from microbiological and chemical analyses of both composting material during the process. Total carbon, total nitrogen, C: N ratio, ash, organic matter, organic matter destroyed, CEC, soluble organic carbon, soluble ammonium and nitrate, ammonium: nitrate ratio and respiration rate were evaluated during 18 weeks. C1 material showed a lower rate of organic matter mineralization probably due to the high proportion of ligneous material. This material reached a greater CEC during the experiment. Increase in CEC during composting is due to conversion of the remaining organic material into humic substances. These results would imply that C1 presented a greater humification level and consequently, a better quality. On the other hand, the greater decrease in soluble organic carbon and NH4+-N values in C2 is in accordance with greater organic matter mineralization. A high decrease in soluble fractions, especially the more degradable ones (water soluble components) indicates a high mineralization of the organic matter during composting and a lower humification level. According to the data obtained in our experiment, some parameters such as CEC, soluble organic carbon and soluble NH4+-N seem to achieve the stability level for both studied materials, while those parameters or indices such as C: N ratio, NH4+-N: NO3?-N ratio indicated stability/maturity only in C2 material during the experimental time.  相似文献   

10.
The quality of compost made from the organic fraction of municipal organic waste (MOW), in terms of organic matter and nutrient concentrations, is inferior to that of compost from other feedstocks. The aim of this work was to improve the quality of MOW compost by means of cocomposting with biosolids (at ratios of 1:1, 2:1, and 3:1 MOW/biosolids) and vermicomposting. Vermicomposting (ground beds with worms) treatments were prepared from traditional pile material after 40 composting days; ground beds without worms were also included. Several parameters, including pH, electrical conductivity, carbon dioxide production, organic matter, total nitrogen, water-soluble carbon, nitrate, ammonium, and extractable phosphorus, were measured throughout the process. Organic matter in the products at 120 days ranged between 39 and 45%, whereas total nitrogen was between 1.7 and 2%. Considering these parameters, the quality of MOW and biosolids cocompost was better than that of MOW composted alone in a previous study (18% organic matter and 0.7% total nitrogen concentration). Extractable phosphorus was also greatly increased from 128 mg/kg in MOW compost to 542–722 mg/kg in the cocompost. Of the three MOW/biosolids ratios employed, only the 2:1 and 3:1 mixtures were adequate for composting and produced similar product qualities. However, the 2:1 mixture required more turnings and exhibited higher N losses. The improvement of quality by vermicomposting was limited. Compared to traditional piles, it did not affect concentrations of organic matter or total nitrogen. The direct action of worms, measured by comparing ground beds with and without worms, increased nitrate concentrations for mixtures 2:1 and 3:1 and extractable phosphorus concentrations for mixture 3:1.  相似文献   

11.
Properties of organic farming composts were examined during the composting process: pH, electrical conductivity, C/N ratio, total N content, NH4+ content, NO3?content, ash content, and organic matter content. In addition to these properties the respiration rate, microbial population counts, hydrolysis of Fluorescein Diacetate (FDA) and the activity of the enzyme amidase were studied. Composts at several stages of maturity were incubated in soil, and their N mineralization rates were measured. The end of the thermophilic stage was characterized by irreversible decrease in pile temperature to under 55°C, followed by stabilization of the chemical properties. This stage in the composting process is also characterized by decrease in CO2 evolution rate, changes in microbial populations and specific patterns in FDA hydrolysis and amidase activity. Based on this evidence, we suggest that biological parameters can be considered as indicators for compost maturity.  相似文献   

12.
The evolution of organic matter of sludge from vegetable oil refining (50%) mixed with turf (40%) and straw (10%) during 6 months of composting was evaluated by physicochemical and spectroscopy analysis. The intense microbial activity is characterized by a significant increase in temperature (over 67°C) during the thermophilic phase (7 days). The final product is characterized by a decomposition rate of 50, C/N ratio about 12, NH4+/NO3? ratio less than 1, and a neutral pH. The lipid analysis showed that total lipids decreased by 83% as a result of biodegradation of lipid compounds of the composted substrate. The degree of polymerization during composting is of about 16%, which provides information on the success of the process. The spectroscopic analysis showed a decrease of the ratios E4/E6 and E2/E6, which clearly shows the humification of organic matter. The physicochemical and spectroscopy parameters of the mixture show the stability and maturity of the final compost, which is confirmed by the germination index (60% for lettuce and turnips, and 90% for cress and lucerna). The results of the evolution of sludge from vegetable oil refining mixed with green wastes produced a mature product that can be applied in agriculture.  相似文献   

13.
Manures lose N through volatilization almost immediately after deposit. Attempts to control losses include the addition of a C source to stimulate nitrogen immobilization. Composting is a treatment process that recommends the addition of carbonaceous materials to achieve a C:N ratio of 30:1 to stimulate degradation and immobilize nitrogen. Dairies near cities may be able to reduce N loss from manures by composting with urban carbonaceous residues such as municipal solid waste (MSW) or MSW compost that, by themselves, have little agronomic value. Studies were conducted using a self-heating laboratory composter where dairy solids were mixed with MSW compost to determine the reduction of N loss during composting. One-to-one mixtures (v/v) of dairy manure solids and MSW compost were composted and NH3 volatilization, CO2 evolution and temperatures were compared to composting of manure alone. Addition of MSW compost resulted in increased CO2 evolution and reduced N loss. Nitrogen loss from composting dairy manure alone was four to ten times greater than that from composting dairy manure mixed with MSW compost. Adjustment of the C:N ratio to 25 by adding MSW compost to manure appeared to be the major factor in reducing N losses.  相似文献   

14.
To accurately predict the potential environmental benefits of energy crops, the sequestration of carbon in soil needs to be quantified. The aim of this study was to investigate the mineralisation rate of the perennial C4 grass Miscanthus giganteus and Miscanthus-derived soil organic matter under contrasting nitrogen supply. Soils were collected from sites where Miscanthus had been grown for 11 and 18 years, respectively, and where a C3-grass (Lolium spp.) had been grown for 7 years. The soils were incubated for 4 months at two levels of soil inorganic nitrogen with or without dead root material of Miscanthus.Addition of root material (residues) increased carbon mineralisation of indigenous organic matter when no nitrogen was added. Added inorganic nitrogen decreased carbon mineralisation in all soils. Nitrogen addition did not affect carbon mineralisation of the residues. Using the 13C fraction to calculate the proportion of respiratory CO2 derived from Miscanthus showed that nitrogen addition decreased carbon mineralisation in soils, but it did not affect carbon mineralisation of the residues. Nitrogen mineralisation was highest in the C3 grass soil without added residues. Nitrification decreased pH, especially in the treatments where nitrogen was added. The Miscanthus-derived organic matter is at least as stable as C3 grassland-derived organic matter. Furthermore, the turnover time of the organic matter increases with time under Miscanthus cultivation.The CENTURY soil organic matter sub-model was used to simulate the organic matter decomposition in the experiment. Carbon mineralisation was accurately simulated but there were unexplained discrepancies in the simulation of the δ13C in the respiration from the treatment with residues. The δ13C in respiration did not decrease with time as predicted, indicating that lignin accumulation did not influence the measurements.  相似文献   

15.
Composting has become an increasingly popular manure management method for dairy farmers. However, the design of composting systems for farmers has been hindered by the limited amount of information on the quantities and volumes of compost produced relative to farm size and manure generated, and the impact of amendments on water, dry matter, volume and nitrogen losses during the composting process. Amendment type can affect the free air space, decomposition rate, temperature, C:N ratio and oxygen levels during composting. Amendments also initially increase the amount of material that must be handled. A better understanding of amendment effects should help farmers optimize, and potentially reduce costs associated with composting. In this study, freestall dairy manure (83% moisture) was amended with either hardwood sawdust or straw and composted for 110-155 days in turned windrows in four replicated trials that began on different dates. Initial C:N ratios of the windrows ranged from 25:1 to 50:1 due to variations in the source and N-content of the manure. Results showed that starting windrow volume for straw amended composts was 2.1 to 2.6 times greater than for sawdust amendment. Straw amended composts had low initial bulk densities with high free air space values of 75-93%. This led to lower temperatures and near ambient interstitial oxygen concentrations during composting. While all sawdust-amended composts self-heated to temperatures >55°C within 10 days, maintained these levels for more than 60 days and met EPA and USDA pathogen reduction guidelines, only two of the four straw amended windrows reached 55°C and none met the guidelines. In addition, sawdust amendment resulted in much lower windrow oxygen concentrations (< 5%) during the first 60 days. Both types of compost were stable after 100 days as indicated by CO2 evolution rates <0.5 mg CO2-C/g VS/d. Both types of amendments also led to extensive manure volume and weight reductions even after the weight of the added amendments were considered. However, moisture management proved critical in attaining reductions in manure weight during composting. Straw amendment resulted in greater volume decreases than sawdust amendment due to greater changes in bulk density and free air space. Through composting, farmers can reduce the volume and weights of material to be hauled by 50 to 80% based on equivalent nitrogen values of the stabilized compost as compared to unamended, uncomposted dairy manure. The initial total manure nitrogen lost during composting ranged from 7% to 38%. P and K losses were from 14 to 39% and from 1 to 38%, respectively. There was a significant negative correlation between C:N ratio and nitrogen loss (R2=0.78) and carbon loss (R2=0.86) during composting. An initial C:N ratio of greater than 40 is recommended to minimize nitrogen loss during dairy manure composting with sawdust or straw amendments.  相似文献   

16.
添加木炭改善猪粪稻壳好氧堆肥工艺及质量   总被引：14，自引：3，他引：11  
为促进农业废弃物的资源化利用,试验以猪粪和稻壳为原料,用化学分析和仪器分析相结合的方法,研究了添加不同质量分数（0、2.5%、5.0%、7.5% 和10.0%）的木炭对60 d猪粪好氧堆肥过程的影响。结果表明：在堆肥有机质的降解过程中,含-OH、-CH3和-CH2基团的化合物的质量分数逐渐减少,含-C=O、C-O-C、-COO基团和含芳香环类物质的质量分数逐渐增加。添加木炭能促使堆肥物料的降解,随着木炭添加量的增加,在60 d的堆肥过程中,各处理有机碳的质量分数分别降低了12.23%、13.77%、14.88%、15.36%和15.86%,碳氮比分别下降了47.80%、54.98%、56.97%、60.03%和65.73%。与对照相比,添加木炭可延长堆肥高温期的停留时间3～ 5 d,增加堆肥物料的持水能力并降低堆肥产品的电导率;同时,添加木炭还能减少堆肥初期氨气的挥发,提高铵态氮的质量分数,促使堆肥后期硝态氮的转化。堆肥结束时,添加木炭可使硝态氮的质量分数提高55.86%～89.32%,总氮的质量分数提高20.55%～53.07%,雪里蕻种子发芽率提高17.6%～41.2%,萌发指数达1.02～1.44。研究表明,添加木炭能促进堆肥有机物料的降解,加快堆肥腐熟脱毒,增加堆肥产品总氮的质量分数,提高产品质量。木炭作为一种潜在的猪粪堆肥添加剂,在促进农业废弃物资源化利用方面具有广阔的应用前景。  相似文献   

17.
Biowaste can be converted into compost by composting or by a combination of anaerobic digestion and composting. Currently, waste management systems are primarily focused on the increase of the turnover rate of waste streams whereas optimisation of product quality receives less attention. This results in low quality composts that can only be sold on bulk markets at low prices. A new market for quality compost could be potting mixes for horticultural container-grown crops to partially replace non-renewable peat and increase the disease suppressiveness of potting mixes. We report here on the effect of wetsieving biowaste prior to composting on compost quality and on disease suppressiveness against the plant pathogen Pythium ultimum of peat mixes amended with this compost. The increased organic matter and decreased salt content of the compost allow for significantly higher substitution rates of peat by compost. In this study up to 60% v/v compost peat replacement did not affect cucumber growth. However, disease suppressiveness of the potting mixes strongly increased from 31 to 94% when the compost amendment rate was increased from 20 to 60%. It was shown that general disease suppression for P. ultimum can only be effective when the basal respiration rate is sufficiently high to support microbial activity. In addition, organic matter of the compost should reach a sufficient stability level to turn from disease conducive to disease suppressive. Increasing the compost addition from 20 to 60% did not significantly affect plant yield, yield variation were due to differences in nutrient levels. It can be concluded that compost from wetsieved biowaste has high potential to replace peat in growing media for the professional market.  相似文献   

18.
R.D. Laura 《Geoderma》1973,9(1):15-26
An experiment was carried out to study effects of 0.25%, 0.50% and 1.0% Na2CO3 on CO2 evolution, nitrogen mineralisation, losses of carbon and nitrogen and humus composition of added gulmohur (Delonix regia) leaves. The CO2 evolution was higher under all levels of alkalinity than in the controls, being highest at 0.5% Na2CO3. Although the process of ammonification was not inhibited at any concentration, the process of nitrification was completely inhibited at 1.0% Na2CO3. The losses of carbon and nitrogen and the ratio of humic to fulvic acids increased with increased alkalinity.  相似文献   

19.
The use of poultry manure or goat/sheep manure in the co-composting of the two-phase olive-mill cake “alperujo” (ALP) with olive leaf (OL) is compared by studying organic-matter mineralization and humification processes during composting and the characteristics of the end products. For this, two different piles (P1 and P2) were prepared using ALP with OL mixed with poultry manure (PM) and goat/sheep manure (GSM), respectively, and composted by the turned windrow composting system. Throughout the composting process, a number of parameters were monitored, such as temperature, pH, electrical conductivity (EC), organic matter (OM), OM losses, total organic carbon (Corg), total nitrogen (Nt), Corg/Nt ratio, and the germination index (GI). In both piles, the temperature exceeded 55 °C for more than 2 weeks, which ensured maximum pathogen reduction. Organic-matter losses followed a first-order kinetic equation in both piles. The final composts presented a stabilized OM and absence of phytotoxins, as observed in the evolution and final values of the Corg/Nt ratio (Corg/Nt < 20) and the germination index (GI > 50 percent). Therefore, composting can be considered as an efficient treatment to recycle this type of waste, obtaining composts with suitable properties that can be safely used in agriculture.  相似文献   

20.
Three composts from citrus-processing industry wastes, sampled at prefixed times during the composting process, were studied with the aim to follow the organic matter evolution by using the isoelectrofocusing (IEF) technique. Results indicated that IEF qualitative analyses allowed evaluation of the organic matter transformation during composting process, showing a decrease of IEF peaks focused at lower values of pH (less stabilized organic matter) and a corresponding increase of peaks focused at higher value of pH (more humified material). The parameter A %, defined as the areas sum of IEF peaks focused at pH>4.7, could be considered particularly effective as a “threshold value” to evaluate the level of organic matter evolution for the considered composts.  相似文献   

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