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1.
J Environ Qual ; 49(1): 228-235, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016360

RESUMO

Manure composting is a common management practice for cattle feedlots, but gaseous emissions from composting are poorly understood. The objective of this study was to quantify ammonia (NH3 ), nitrous oxide (N2 O), carbon dioxide (CO2 ), and methane (CH4 ) emissions from windrow composting (turning) and static stockpiling (nonturning) of manure at a commercial feedlot in Australia. An inverse-dispersion technique using an open-path Fourier transform infrared (OP-FTIR) spectrometer gas sensor was deployed to measure emissions of NH3 , N2 O, CO2 , and CH4 over a 165-d study period, and 29 and 15% of the total data intervals were actually used to calculate the fluxes for the windrow and stockpile, respectively. The nitrogen (N) lost as NH3 and N2 O emissions represented 26.4 and 3.8% of the initial N in windrow, and 5.3 and 0.8% of that in the stockpile, respectively. The carbon (C) lost as CO2 and CH4 emissions represented 44 and 0.3% of the initial C in windrow, and 54.8 and 0.7% of that in the stockpile, respectively. Total greenhouse gas (GHG) emissions from the manure windrow were 2.7 times higher than those of the stockpiled manure. This work highlights the value that could be accrued if one could reduce emissions of NH3 -N and N2 O-N from composting, which would retain manure N content while reducing GHG emissions.


Assuntos
Compostagem , Animais , Austrália , Bovinos , Gases , Efeito Estufa , Esterco
2.
J Environ Qual ; 49(3): 745-753, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016408

RESUMO

Manure is commonly used as a fertilizer or soil conditioner; however, land application of untreated manure may introduce pathogens and antibiotic-resistant bacteria (ARB) into the soil, with harmful implications for public health. Composting is a manure management practice wherein a carbon-rich bulking agent, such as corn (Zea mays L.) stalk residue, is added to manure to achieve desirable carbon/nitrogen ratios to facilitate microbial activities and generate enough heat to inactivate pathogens, including antibiotic-resistant pathogens. However, when comparing compost piles and stockpiles for ARB reduction, we noticed that bulking agents added ARB to composting piles and compromised the performance of composting in reducing ARB. We hypothesized that ARB could be prevalent in corn stalk residues, a commonly used bulking agent for composting. To test this hypothesis, corn stalk residue samples throughout Nebraska were surveyed for the presence of ARB. Of the samples tested, 54% were positive for antibiotic-resistant Escherichia coli or enterococci using direct plating or after enrichment. Although not statistically significant, there was a trend wherein the use of pesticides tended to result in a greater prevalence of some ARB. Results from this study suggest that bulking agents can be a source of ARB in manure composting piles and highlight the importance of screening bulking agents for effective ARB reduction in livestock manure during composting.


Assuntos
Compostagem , Antibacterianos , Bactérias , Esterco , Nebraska , Zea mays
3.
J Environ Qual ; 49(2): 483-495, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016434

RESUMO

To manage nitrogen (N) efficiently, organic growers must be able to predict the amount and timing of plant-available N from organic amendments. In this study, we measured N mineralization from a variety of organic amendments, including composted animal manures and plant material, pelleted and granular organic fertilizer formulations, slaughter waste products, and hydrolyzed liquid fertilizers. In a laboratory incubation, we measured net N mineralization from materials mixed with either organically or conventionally managed soil at 23°C and 60% water holding capacity after 0, 7, 21, 42, and 84 d. We found that net mineral N change in the amended soils after 84 d of incubation fell into four categories: immobilization to 5% of applied N for yard trimmings composts, 15-30% for poultry manure composts, 35-55% for granular fertilizers, and 60-90% for quick release products. However, across all amendments the amount of plant-available N after 84 d of incubation was well correlated with the carbon (C)/N ratio (R2  = 0.92). Within amendment types, the C/N ratio predicted N mineralization for yard trimmings composts (R2  = 0.91), manure composts (R2  = 0.81), and specialty fertilizer and slaughter products (R2  = 0.88) but not liquid products (R2  = 0.11). Soil management history did not consistently affect net N mineralization but may have influenced timing.


Assuntos
Compostagem , Nitrogênio/análise , Animais , Fertilizantes , Esterco , Solo
4.
J Environ Qual ; 49(4): 1020-1031, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33016488

RESUMO

A study was conducted to test the suitability of a range of organic and inorganic residuals mixed with municipal biosolids to create a soil amendment effective for a broad range of end uses. Biosolids suitable for unrestricted use were sourced from San Francisco, CA. Residuals including urban wood and yard waste, nut shells, biochar, and sawdust were sourced from nearby producers. Existing biosolids based soil products, peat, and a yard-food compost were used as controls. Experimental mixtures were tested for a range of soil properties, appearance, odor, germination, and growth response. Several mixtures performed as well as or better than the yard-food compost, and several performed comparably to the biosolids soil controls. Yard waste fines blended with biosolids in a 50:50 ratio by volume or yard waste fines blended with biosolids and 20% sand at 40:40:20 were highly effective across all measured indices. Mixed yard and recycled lumber fines blended with biosolids at these same ratios performed similarly well. Blends with a high percentage of char performed poorly in germination and growth response, likely as a result of elevated electrical conductivity. Certain blends such as gypsum and redwood shavings failed to mix well with biosolids to create a uniform looking material and were less visually appealing. In general, blends that met established quality control parameters for compost performed well on the measured indices. These results suggest that blending Class A biosolids with organic and inorganic feedstocks to meet quality criteria developed for compost will create marketable soil products.


Assuntos
Compostagem , Poluentes do Solo/análise , Biossólidos , Sulfato de Cálcio , Solo
5.
Waste Manag ; 118: 655-666, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011543

RESUMO

Anaerobic sludge originating from the co-digestion of used disposable nappies and expired food products treated in a pilot two-stage system was examined as feed material for a continuous pilot-scale composter (capacity: 300 L feed per week). The feed materials and final compost products were analyzed and evaluated for their suitability as compost materials. Ιn terms of stability, the compost products were identified as stable through static respiratory index measurement (0.11-0.24 g O2/(kg Volatile Solids h)), heavy metals concentrations were within acceptable limits (i.e. concentration of Cu, Cd, Zn, Pb, Cr, As lower than 1 mg/kg dry mass) as well as polycyclic aromatic hydrocarbons (0.06-0.34 mg/kg dry mass lower than 6 mg/kg dry mass). During composting, significant losses of nitrogen from the digestate and the urea added for C/N correction were observed (51-75%), indicating that the adjustment of C/N ratio through the addition of chemicals is not efficient in composting processes with forced aeration and the pre-existing nitrogen in digestate was susceptible to air-stripping. The continuous composting process implemented proved capable of producing mature compost with a retention time of 14 d. The final products were within acceptable limits for all the parameters examined, except for the presence of pathogens (Salmonella and Enterococcus) which were not eliminated, even though the composter reached 56 °C for 3-4 days at the thermophilic stage. The characteristics of the anaerobic sludge samples examined indicate that direct land application of the anaerobic effluent should be considered as an option.


Assuntos
Compostagem , Metais Pesados , Anaerobiose , Metais Pesados/análise , Esgotos , Solo
6.
Chemosphere ; 258: 127405, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947677

RESUMO

Chelation of lead (Pb) is an important factor in enhancing the Pb mobility thereby improving availability to promote phytoremediation of Pb from contaminated soil. The study was conducted to evaluate the effect of amendments in enhancing the phytoremediation of Pb in soil. For this purpose, soil was spiked to obtain desired Pb concentrations (0-1500 mg kg-1) and pots were filled. One month old and uniform seedlings of Pelargonium hortoum were transplanted into each pot. Five different amendments i.e. compost (0-10%), ammonium nitrate (0-10 mmol kg-1), TiO2NPs (0-100 mg kg-1), citric acid (0-10 mmol kg-1) and EDTA (0-5 mmol kg-1), were applied. Overall, ammonium nitrate, EDTA and citric acid application increased the Pb concentration, however, compost and TiO2NPs decreased the concentration in roots and shoots. At 1500 mg Pb kg-1, Pb concentration in shoots was increased by 0.9-, 0.6- & 0.8-folds and in roots by 1.8-, 1.3- & 1.7-folds upon EDTA, ammonium nitrate and citric acid application, respectively. TiO2NPs and compost application decreased Pb concentration by 29% & 35% in shoots and 25% & 51% in roots, respectively. At the highest level of Pb (1500 mg kg-1), plant biomass was increased by 26.6%, 19.5%, 17.9% and 18.4% upon application of compost, TiO2 NPs, ammonium nitrate and citric acid, respectively. However, EDTA reduced the plant dry biomass by 28.4%. The accumulated Pb content was recovered as Pb-nanoparticles, which were in anatase phase, size ranged between 98 and 276 nm. Among all the studied amendments, citric acid efficiently increased Pb phytoaccumulation without any toxicity.


Assuntos
Biodegradação Ambiental , Chumbo/análise , Poluentes do Solo/análise , Biomassa , Quelantes , Ácido Cítrico , Compostagem , Ácido Edético , Chumbo/metabolismo , Pelargonium , Raízes de Plantas , Solo , Poluentes do Solo/metabolismo
7.
Waste Manag ; 118: 552-562, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32980734

RESUMO

The increasing concern with greenhouse gas emissions and nutrients cycling creates a need for cost-effective, practical and environmentally sensible biowaste management strategies. Centralized systems have struggled to comply with those needs. Decentralized systems, treating waste at source, promise local nutrient circularity and increased resource sovereignty. The large-scale performance of decentralized systems remains unclear, especially concerning the local sink capacity to assimilate the treatment products. This study aimed to compare centralized and decentralized systems for the region of Porto and assess whether creating additional urban farms could reduce costs and environmental impacts. Spatial analysis was used to assess waste generation, potential compost bin locations, peri-urban and potential urban farmland available, and collection and transport requirements. The carbon footprint of different scenarios was determined using life-cycle assessment. The results show that local composting led to cost savings over centralized systems. However, this system encompassed positive carbon emissions and most districts evidenced limited sink capacity for compost application. Additional urban farms added significant sink capacity, however, their impact on cost and carbon footprint was insignificant. The carbon footprint of centralized systems was heavily dependent on factors influencing collection such as population density, and affected by the renewable content of the electricity grid. Anaerobic digestion was the most climate-friendly option in the urban center and local composting in remote and less dense districts. Municipalities may benefit from tailoring the treatment systems to specific districts, creating additional jobs while reducing cost and climate impacts overall.


Assuntos
Compostagem , Gases de Efeito Estufa , Pegada de Carbono , Cidades , Fazendas
8.
Waste Manag ; 118: 360-368, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32927389

RESUMO

Available information on passivation effect of biochar on heavy metals (HMs) through regulating bacterial communities remains limited. Thus, this study investigated the correlation between bacterial diversity and HM-fractions (Zn, Cu, Cd, Cr and Pb) during composting with different dose of biochar (5% and 10%, dry weight basis), in order to ascertain the passivation effect on HMs under the influence of bacterial community. The addition of 10% biochar showed better passivation effect with reduction in bioavailability factor (BF) of Zn, Cu, Cd and Pb by 4.10%, 44.12%, 18.75% and 30.06%, respectively. In addition, it brought forward the variation in primary bacterial phylum to the thermophilic phase. The results of redundancy analysis (RDA) and structural equation models (SEMs) indicated that C:N ratio was an important factor in controlling the morphological transformation of HM by affecting the bacterial community structure. Our results maybe provide a novel insight into HM-passivation from an interaction mechanism on C:N ratio and bacterial community.


Assuntos
Compostagem , Metais Pesados , Poluentes do Solo , Carvão Vegetal , Metais Pesados/análise , Solo , Poluentes do Solo/análise
9.
Water Sci Technol ; 81(11): 2441-2449, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32784287

RESUMO

Municipal sludge disposal and recycle has become a prominent research theme. In this study, a sequential process for integral treatment of municipal sludge was primarily presented, combining acid leaching, anion exchange and aerobic composting. The aim of the process was to remove chromium (Cr) from the sludge and reuse the sludge as manure. Firstly, Cr was removed from municipal sludge via the acid leaching process; the removal rate was up to 57.43%. Then, ion exchange resin was used to remove Cr from leachate; the removal rate reached 95%. Aluminum sheet was used to replace the Cr from eluent; the replacement rate was 63.3%. The aerobic composting process could be successfully warmed up to above 55 °C and lasted for 4 days; the seed germination index reached 68.3%. After the composting process, the residual Cr in sludge mainly existed at a more stable residual state and organic binding state. Overall, this novel sequential process serves as a potential high-efficiency, green, low-energy way for municipal sludge recycle.


Assuntos
Compostagem , Ânions , Esterco , Reciclagem , Esgotos
10.
Environ Monit Assess ; 192(9): 563, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32757091

RESUMO

As the composting industry develops rapidly in the world, the compost producers have focused on the efficiency of energy utilization in production without restricting the quality of compost in the forced ventilation systems. Therefore, this experimental study quantified the impacts of initial C/N ratio on aeration requirement and energy consumption due to aeration for reactor composting of rose pomace through kinetics of the process using fifteen 100-l composting reactors. The results of the study showed that initial C/N ratio significantly affected decomposition rate, compost maturity, and dry matter losses and organic matter losses (P < 0.05). The maximum decomposition rate (0.072 day-1) and the highest degree of progression of the composting process existed at the mixture with initial C/N ratio of 24.26. The results underlined the importance of the initial C/N of composting of rose pomace in terms of energy consumption due to aeration. In particular, more mature compost within a short time can be obtained when composting was operated with a C/N ratio of 23.7-25.8 in the expense of requiring more airflow rate, fan power, and energy consumption by aeration fan per composting material.


Assuntos
Compostagem , Rosa , Monitoramento Ambiental , Cinética , Solo
11.
Environ Pollut ; 265(Pt A): 114202, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806409

RESUMO

Poultry manure is a reservoir for antibiotics and antibiotic resistance genes and composting is an effective biological treatment for manure. This study explored the effect of using two methods of adding a complex microbial agent to the composting of laying-hen manure on doxycycline degradation and tetracycline resistance genes elimination. The results showed that incorporating a complex microbial agent at 0.8% (w/w) on the 0th and 11th day (group MT2) effectively degraded doxycycline with a final degradation rate of 46.83 ±â€¯0.55%. The half-life of doxycycline in this group was 21.90 ±â€¯0.00 days and was significantly lower than that of group MT1 (1.6% (w/w) complex microbial agent added on the 0th day) and group DT (compost without complex microbial agent). But there was no significant difference in the final degradation rate of doxycycline between group DT and group MT1. The addictive with the complex microbial agent changed the microbial community structure. Bacteroidetes, Firmicutes and Proteobacteria were the dominant phyla during composting. Aerococcus, Desemzia, Facklamia, Lactobacillus, Streptococcus, and Trichococcus were the bacteria related to the degradation of doxycycline. Moreover, the incorporation of a complex microbial agent could decrease the risk on spreading tetracycline resistance genes. The single addition promoted the elimination of tetM, whose possible hosts were Enterococcus, Lactobacillus, Staphylococcus, and Trichococcus. Adding the complex microbial agent twice promoted the elimination of tetX, which was related to the low abundance of Chryseobacterium, Flavobacterium and Neptunomonas in group MT2. Redundancy analysis showed that the bacterial community, residual doxycycline and physiochemical properties have a potential effect on the variation in tetracycline resistance genes levels. Overall, adding the complex microbial agent twice is an effective measure to degrade doxycycline.


Assuntos
Compostagem , Animais , Antibacterianos/farmacologia , Galinhas , Doxiciclina , Feminino , Esterco , Resistência a Tetraciclina
12.
J Environ Manage ; 273: 111179, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771853

RESUMO

The addition of organic wastes is a common agronomic practice in some Mediterranean regions to increase soil organic matter. In addition, they consume high amounts of agrochemicals. Hand-packed soil columns were used to evaluate the effect of three different composted organic soil amendments (agro-forestry, agro-industrial and animal manure) on the leachability of eight persistent herbicides. A new leaching index based on the amounts recovered from leachates and referred as Experimental Leaching Index (ELI) is proposed according to the mean annual precipitation in a specific place. This index is compared with others such as Groundwater Ubiquity Score (GUS), Relative Leaching Potential Index (RLPI) and Leachability Index (LIX), which only include degradation (DT50) and sorption (KOC) parameters. According to ELI, metribuzin is very mobile in all cases, while terbuthylazine, chlorotoluron and isoproturon present high leachability only in unamended soil reducing their leaching potential in amended soils. Aclonifen, oxyfluorfen, trifluralin and pendimethalin behave in all cases as immobile (non-leacher) compounds.


Assuntos
Compostagem , Água Subterrânea , Herbicidas/análise , Poluentes do Solo/análise , Animais , Solo
13.
Environ Pollut ; 266(Pt 3): 115202, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32823065

RESUMO

Bioremediation has gained global prominence as an effective method for treating hydrocarbon-contaminated drill mud waste (HCDW). However, the problem of low nutrient content, bioavailability and microbial presence remain largely unresolved. In this study, the synergistic effects of compost, cow bile and bacterial culture on the degradation rate of HCDW was investigated. A homogenized HCDW sample (80 kg) obtained from 25 different drill mud tanks was divided into 20 portions (4 kg each) and each adjusted to 1.4% nitrogen content + 20 ml cow bile (i.e., basic treatment). Pure cultures of Brevibacterium casei (Bc) and Bacillus zhangzhouensi (Bz) and their mixture (BcBz) were subsequently added to 12 of the amended HCDW (basic) to undergo a 6-week incubation. A portion of the unamended HCDW (2 kg) was used as control. Initial pH, electrical conductivity and surface tension values of the HCDW were 8.83, 2.34 mS/cm and 36.5 mN/m, respectively. Corresponding values for total petroleum hydrocarbon (TPH), total nitrogen and total plate count bacteria were 165 g/kg, 0.04% and 4.4 × 102 cfu/ml. The treatments led to a substantial reduction in TPH (p < 0.05) while the control had no significant effect (p > 0.05). TPH reduction after the experimental period occurred in the order: basic + BcBz (99.7%) > basic + Bz (99.5%) > basic + Bc (99.2%) > basic (95.2%) > control (0.06%). Multiple regression analysis revealed significant effect of total plate count, pH, CN ratio and electrical conductivity (R2 = 0.87, p = 0.05) on the degradation of TPH in the HCDW. The study demonstrates strong interactive effects of compost, cow bile and bacteria culture on the remediation of HCDW, which can be applied to boost the efficiency of the bioremediation technique.


Assuntos
Compostagem , Petróleo , Poluentes do Solo/análise , Animais , Bile , Biodegradação Ambiental , Brevibacterium , Bovinos , Feminino , Hidrocarbonetos , Solo , Microbiologia do Solo
14.
J Environ Manage ; 272: 111109, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32854897

RESUMO

Heavy metals (HM) pollution is a major limitation to the application of composting products. Therefore, mitigating the toxicity of HM has attracted wide attention during composting. The toxicity of HM is mainly acted on microorganisms during composting, and the toxicity of different HM speciation is obviously various. There are many pathways to change the speciation to reduce the toxicity during composting. Therefore, in this review, the speciation distribution, toxicity mechanism and remediation ways of HM during composting were discussed in order to better solve HM pollution. The microbial remediation technology holds enormous potential to remediate for HM without damaging composting, however, it is hard to extract HM. The innovation of this review was to outline microbial remediation strategies for HM during composting based on two mechanisms of microbial remediation: extracellular adsorption and intracellular sequestration, to solve the problem how to extract microbial agents from the compost. Ultimately, a novel theoretical method of microbial remediation was proposed to remove HM from the compost.


Assuntos
Compostagem , Metais Pesados/análise , Poluentes do Solo/análise , Poluição Ambiental , Solo
15.
Ecotoxicol Environ Saf ; 202: 110907, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800242

RESUMO

The impact of bioaerosols in municipal solid waste management is nowadays identified as a growing health concern worldwide. In this study, exposure to endotoxin in composting facilities and its association with lung function and clinical symptoms was investigated in Tehran municipal solid waste management complex (Aradkooh) as one of the largest solid waste management facilities in the Middle East. Airborne endotoxins were collected between June and July 2019 and the concentrations were determined by Limulus Amebocyte Lysate (LAL) method. Healthy workers with no history of respiratory disease were recruited and data on clinical symptoms (cough, phlegm, wheezing, dyspnea, fatigue, headache, eye irritation, runny nose, runny eyes, and sore throat) was obtained by the modified American Thoracic Society questionnaire, and spirometric measurement was performed by an expert. The binary logistic regression test was used and adjusted for confounding variables. The results didn't show any difference in lung function parameters (FEV1, FVC, FEV1/FVC, PEF, FEF25-75%), and most of the respiratory symptoms despite a relatively high difference in the concentration of endotoxin observed in air samples of different locations. Only the increased risk of cough (OR 10.5, 95% CI: 2.4 to 44.8 in the moderately exposed group and 7.8, 95% CI: 1.6 to 39.1 in highly exposed ones), fatigue (OR 3.7, 95% CI: 1.2 to 11.7), and headache (OR 6.02, 95% CI: 1.4 to 24.5) were found in the exposed groups compared to controls after adjusting for age, active and passive smoking. However, findings of the study might be underestimated due to some issues including healthy worker effect, intra and intersubject variability, and self-reporting bias, thereby the results should be interpreted with caution. Although we did not find any relationship, due to the high concentrations of endotoxins observed in some sites, it is recommended to consider some possible prevention measures such as using personal protective equipment to reduce the exposure of workers at an acceptable level.


Assuntos
Poluentes Ocupacionais do Ar/análise , Compostagem , Endotoxinas/análise , Exposição Ocupacional/estatística & dados numéricos , Doenças Respiratórias/epidemiologia , Adulto , Microbiologia do Ar , Feminino , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Testes de Função Respiratória/efeitos adversos , Sons Respiratórios , Doenças Respiratórias/etiologia , Poluição por Fumaça de Tabaco
16.
J Environ Manage ; 274: 111193, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32810680

RESUMO

Composting represents a suitable and cheap method for handling and processing seaweeds accumulated on the coast. Within this framework, two seaweed composts were prepared, one with Undaria pinnatifida accumulated in spring-summer and other with a mixture of seaweeds accumulated in autumn-winter, both from Central Patagonian beaches. The effect of these two composts was evaluated experimentally as an amendment for the growth of Sarcocornia perennis (chickenclaws), a plant species dominating Patagonian salt marshes. Both composts were applied at 75, 50, and 25% doses with perlite. The analysis of the compost properties (phytotoxicity test, C/N, electrical conductivity, pH, and metal content) allowed characterizing both composts as matures and stables. The growth results showed that both composts allow the growth of S. perennis in all doses tested; however, Undaria compost was better in the stimulation of vegetative growth when applied in dose 50%, followed by 75% of both composts. For these reasons, both composts from seaweed waste accumulated on Patagonian coasts could be used in the growth of S. perennis and potentially other plant species, giving value to the seaweeds that currently are considered a waste that disturb these coasts and are discarded without use.


Assuntos
Chenopodiaceae , Compostagem , Alga Marinha , Metais , Solo , Verduras
17.
Bioresour Technol ; 316: 123915, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32739574

RESUMO

This study was evaluated industrial waste fine coal gasification slag (FCGS) as an additive on pig manure composting by parameters of greenhouse gases, NH3, volatile fatty acids (VFAs) and maturity. Six treatments of FCGS (0%, 2%, 4%, 6%, 8% and 10%) were added into the mixture raw material and composted 42 days. Results illustrated that the FCGS amendment could prolong sanitation stage and promote the degree of maturity, germination index and C/N ratio during composting. With the increasing amendment of FCGS, GI was increased from 9.97 to 28.45%. Compared with control, increasing of FCGS proportion could reduce the mitigation of global warming potential (N2O and CH4), NH3 and cumulative of VFAs from 8.89-77.04%, 3.81-71.65%, 5.18-28.02% and 8.79-83.33%. Finally, present study results revealed that 10%FCGS could improve composting and reduced the maturity period as well as compost quality, thus recommended as effective dosage for efficient pig manure composting.


Assuntos
Compostagem , Gases de Efeito Estufa , Animais , Carvão Mineral , Ácidos Graxos Voláteis , Esterco , Nitrogênio/análise , Solo , Suínos
18.
Bioresour Technol ; 316: 123946, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32769001

RESUMO

The agri-food waste (AW) require amendments for composting to adjust nutritional and physicochemical deficiencies. The theoretical mixtures formulation is difficult to reach on an industrial scale. The main objective of this work was to evaluate to what extent the composition of AW-based mixtures determines the quality of the final compost produced at the industrial scale. Raw materials having the same AW share characteristics, irrespectively of the amendments added, but their compost were different. All the materials were biological stable at the cooling phase, and mature enough at the end, although the degree of humification did not match with the absence of phytotoxicity. The final compost had sufficient quality even though the AW-based raw materials have a low C/N ratio (<20) and other characteristics such as high electrical conductivity (13 mS·cm-1) and pH (<8.5) that are unfavorable for composting. The management operations during industrial composting correct the deficiencies of raw materials.


Assuntos
Compostagem , Eliminação de Resíduos , Carbono , Alimentos , Resíduos Industriais/análise , Nitrogênio/análise , Solo
19.
Bioresour Technol ; 316: 123905, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32777720

RESUMO

Emission of nitrous oxide (N2O) during animal manure composting is of great concern, and its emission factor (EF) is important for greenhouse gas emission inventory, while the EF is still uncertain due to limited on-site full-scale observations worldwide. In this study, N2O emissions were monitored during different seasons in a full-scale swine manure windrow composting with pile volume of about 76.5 m3. The results showed that the maximum N2O flux during the cold season (CS) was 23 times higher than during the warm season (WS), significant differences in the contribution to direct N2O emissions were observed in three composting stages, and shaded-side N2O emission was higher than sunny-side emission. The direct N2O emission factors of animal manure composting were 0.0046, 0.0002 kg N2O-N/kgTN (dry weight) in the CS and WS, respectively. Scenario analysis results showed that windrow composting is a suitable manure management that emits less N2O than solid storage.


Assuntos
Compostagem , Gases de Efeito Estufa , Animais , Esterco , Metano/análise , Óxido Nitroso/análise , Estações do Ano , Solo , Suínos
20.
Bioresour Technol ; 316: 123823, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32795866

RESUMO

In this study, green soybean hulls and maize straw were used for composting to explore the dynamics of material conversion, bacterial and fungal communities and metabolic functions. The results showed that bacterial and fungal communities had different temporal successions during composting. The bacterium Streptosporangiaceae was a biomarker in the thermophilic stage of composting, and the fungus Chaetomiaceae was a biomarker in the thermophilic stage and cooling stage. In the bacterial network, the germination index (GI) had a time-delayed association with Truepera, Pseudomonas and Methylococcaceae, which represented the key physicochemical characteristics that affect the community. In the fungal community, the GI, pH, fulvic acid (FA) and temperature etc. had a joint effect. Carbohydrate metabolism and amino acid metabolism were the main metabolic pathways, and saprotrophs represented the dominant fungal trophic mode in the composting process. These results provide a reference from screening specific and efficient agents to accelerate natural vegetable composting.


Assuntos
Compostagem , Microbiota , Micobioma , Bactérias , Esterco , Solo , Soja
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