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[Display omitted] • The aim was to elucidate the gas emission and bacterial succession in response to the different length of chopped cornstalk during composting. • The most active mannerization process can be observed by applying 5 cm of corn stalk. • 5 cm of straw amendments can distinctly ammolite the greenhouse effects during composting. • The application of 5 cm of straw can strengthen the connection and activity of predominating bacterial members. In present study, four lengths of chopped cornstalks were amended with pig manure respectively for 100 days aerobic fermentation, which aimed to evaluate the impact of different length of agricultural solid wastes on gaseous emission and dominating bacterial community succession and connection. The result revealed that the maximum ammonia volatilization was observed in 5 cm of straw samples attributed to the prominent mineralization, which was opposite to the emission of CH 4 and N 2 O. As for global warming potential, the minimum value was detected in 5 cm of straw samples, which decreased by 5.03–24.75% compared with other samples. Additionally, the strongest correlation and complexity of bacterial community could be detected in 5 cm of straw treatment, representing the most vigorous bacterial metabolic ability could be recorded by optimizing the microbial habitat. Therefore, in order to decline the greenhouse effect in livestock manure composting, the 5 cm of corn straw was recommended. [ABSTRACT FROM AUTHOR]

In this study, the main objective was to investigate the potential effect of tertiary-amine modified bentonite (TAMB) on the nitrogen transformation and the volatile fatty acids (VFAs) degradation during the chicken manure (CM) composting. Six dosages of TAMB (0%, 2%, 4%, 6%, 8% and 10%) were amended into the mixture of CM and wheat straw and then composted for 50 days. The results revealed the TAMB amendment could prolong the thermophilic phase and enhance the organic matter (OM) degradation. With the increasing dosage of TAMB, the ammonia volatilization was reduced by 15.41%–65.35%. Meanwhile, the TAMB addition had a positive effect on VFAs degradation and reducing odor unit MAX (OU MAX ) by 17.61%–59.24%. Moreover, CH 4 was reduced by 12.15%–32.78% in TAMB applied treatments compared to control. Finally, combined with all results, it indicated that TAMB amendment could reduce VFAs, CH 4 emission and nitrogen loss to improve the compost quality. [ABSTRACT FROM AUTHOR]

The aim of this work was to compare the impact of biochar, zeolite and their mixture on nitrogen conservation and organic matter transformation during pig manure (PM) composting. Four treatments were set-up from PM mixed with wheat straw and then applied 10% biochar (B), 10% zeolite (Z) and 10% biochar + 10% zeolite (B + Z) into composting mixtures (dry weight basis), while treatment without additives applied used as control. Results indicated that adding B, Z and B + Z could obviously ( p < 0.05) improve the organic matter degradation and decrease the nitrogen loss. And combined addition of B and Z further promoted the organic matter humification and reduced the heavy metals mobility. Meanwhile the highest mitigation of ammonia (63.40%) and nitrogen dioxide (78.13%) emissions was observed in B + Z added treatment. Comparison of organic matter transformation, nitrogen conservation and compost quality indicated that the combined use of biochar and zeolite could be more useful for PM composting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Particle size of branch on enzymatic activity and gaseous emissions during composing were assessed. • The contaminations of greenhouse gases were regulated by amending 2 cm of branch. • The active microbial assimilation and catabolism were ameliorated by applying 2 cm of branch. • The application of 2 cm of branch facilitated the enzymatic activities by optimizing benefiting habitat. The purpose of current study was to probe the effect of various length of branch on gaseous emissions and vital enzymatic activity. Four lengths (< 2 cm, 2 cm, 5 cm, and > 5 cm) of clipped branch were mingled with collected pig manure for 100 days aerobic fermentation. The consequence demonstrated that the amendment of 2 cm of branch showed conducive to decline the greenhouse gas emissions, which the CH 4 emissions decreased by 1.62–40.10%, and the N 2 O emissions decreased by 21.91–34.04% contrasted with other treatments. Furthermore, the peak degree of enzymatic activities was also observed in 2 cm of branch treatment by the optimizing living condition for microbes. In view of microbiological indicators, the most abundant and complex bacterial community could be monitor in 2 cm of branch composting pile, which verified the microbial facilitation. Summing up, the strategy of 2 cm branch amendment would be recommended. [ABSTRACT FROM AUTHOR]

• The leachates released from MPs under different aging conditions were studied. • DOC releasing characteristics were related to MP' type and aging condition. • MPs were mainly prone to release protein-like and hydrophilic substances. • More small sizes and rough NPs were released in UV-aged treatments. • UV irradiation aggravated the toxicity of leachate released from MPs. Despite numerous studies that have been devoted to investigating the aging behaviors of microplastics (MPs), dissolved organic carbon (DOC) and nano-plastics (NPs) released from MPs under different aging conditions were limited. Herein, the characterizations and underlying mechanisms of DOC and NPs leaching from MPs (PVC and PS) in the aquatic environment for 130 days under different aging conditions were investigated. The results showed that aging could reduce the abundance of MPs, and high temperature and UV aging generated small-sized MPs (< 100 μm), especially UV aging. DOC-releasing characteristics were related to MP type and aging condition. Meanwhile, MPs were prone to release protein-like and hydrophilic substances except for 60 °C aging of PS MPs. Additionally, 8.77 × 109–8.87 × 1010 and 4.06 × 109–3.94 × 1010 NPs/L were detected in leachates from PVC and PS MPs-aged treatments, respectively. High temperature and UV promoted the release of NPs, especially UV irradiation. Meanwhile, smaller sizes and rougher NPs were observed in UV-aged treatments, implying higher ecological risks of leachates from MPs under UV aging. This study highlights the leachate released from MPs under different aging conditions comprehensively, which could offset the knowledge gap between the MPs' aging and their potential threats. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Particle size of amendments on carbon conversion during composting was evaluated. • Organic matter transformation accelerated by adding 2 cm and 5 cm of branch and straw during composting. • The highest degree of humification was detect in 2 cm and 5 cm of branch and straw treatments. • 2 cm and 5 cm of branch and straw increased the abundance of humus funguses. For purpose of clarifying the impact on particle size of bulking agents on humification and relevant mechanisms, different length (<2 cm, 2 cm, 5 cm, 10 cm) of branch and straw were blended with swine manure individually for 100 days aerobic composting. Results demonstrated that, 2 cm and 5 cm of branch and straw promoted the highest degradation of DOC by 41.49 % and 58.42 %, and increased the humic substances by 23.81 % and 55.82 % in maturity stage, respectively, compared with other treatments. As shown in microbial consequence, the maximum relative abundance of humus funguses increased by 99.55 % and 99.92 % at phylum, and 98.95 % and 99.24 % at genus in 2 cm and 5 cm of branch and straw treatment, thus verifying the result in variation of humus content. In a word, particle size could result in obvious impact on humification, and the optimized size were about 2 cm and 5 cm of branch and straw. [ABSTRACT FROM AUTHOR]

Biodegradation of microplastics (MPs) in contaminated biowastes has received big scientific attention during the past few years. The aim here is to study the impacts of livestock manure biochar (LMBC) on the biodegradation of polyhydroxyalkanoate microplastics (PHA-MPs) during composting, which have not yet been verified. LMBC (10% wt/wt) and PHA-MPs (0.5% wt/wt) were added to a mixture of pristine cow manure and sawdust for composting, whereas a mixture without LMBC served as the control (CK). The maximum degradation rate of PHA-MPs (22–31%) was observed in the thermophilic composting stage in both mixtures. LMBC addition significantly (P < 0.05) promoted PHA-MPs degradation and increased the carbon loss and oxygen loading of PHA-MPs compared to CK. Adding LMBC accelerated the cleavage of C–H bonds and oxidation of PHA-MPs, and increased the O–H, C O and C–O functional groups on MPs. Also, LMBC addition increased the relative abundance of dominant microorganisms (Firmicutes , Proteobacteria , Deinococcus-Thermus , Bacteroidetes , Ascomycota and Basidiomycota) and promoted the enrichment of MP-degrading microbial biomarkers (e.g., Bacillus , Thermobacillus , Luteimonas , Chryseolinea , Aspergillus and Mycothermus). LMBC addition further increased the complexity and connectivity between dominant microbial biomarkers and PHA-MPs degradation characteristics, strengthened their positive relationship, thereby accelerated PHA-MPs biodegradation, and mitigated the potential environmental and human health risk. These findings provide a reference point for reducing PHA-MPs in compost and safe recycling of MPs contaminated organic wastes. However, these results should be validated with other composting matrices and conditions. •Manure biochar (MBC) enhanced PHA microplastics biodegradation during composting. •MBC increased carbon loss and oxygen loading of PHA microplastics. •MBC changed the composition and structure of microbial community. •MBC increased the relative abundance of microorganisms for degrading microplastics. • MBC enhanced the connectivity between biomarkers and MPs degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Degradation of various microplastics during composting was investigated. • The abundance of PE and PHA microplastics decreased by 13–29%. • The carbon content of all microplastics were reduced by 17–30%. • MPs decreased the richness and diversity of bacteria in thermophilic phase. The objectives of this study were to investigate the degradation characteristics of different microplastics (polyethylene (PE), polyvinyl chloride (PVC), polyhydroxyalkanoates (PHA)) and their effect on the bacterial community during composting. In this study, 0.5% PE, 0.5% PVC and 0.5% PHA microplastics were individually added to the mixture of cow manure and sawdust and then composted for 60 days. The treatment without microplastics was regarded as control. Results indicated that the abundance and smaller size (0–800 μm) of microplastics in all treatments obviously decreased after composting, except PVC treatment. The surface morphology of all microplastics occurred obvious erosions and cracks and the carbon content of PE, PVC and PHA microplastics were reduced by 30, 17 and 30%, respectively. After composting, all microplastics were significantly oxidized and the functional groups O–H, C=O and C–O increased. Furthermore, all microplastics exposure reduced the richness and diversity of bacteria community at thermophilic phase, especially PVC microplastics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diatomite (DM) had no obvious negative effect on maturity of composts. • DM promoted the transformation from NH 4 +-N to AAN and HUN, and thus reduced N loss. • The optimum added dosage of DM in pig manure composting was at 10% among 0–20%. • 10% DM reduced the relative abundance of narG, nirS , nirK and nosZ. The aim of this study was to investigate the pathways and mechanisms of nitrogen transformation during the composting process, by adding diatomite (0%, 2.5%, 5%, 10%, 15% and 20%) into initial mixtures of pig manure and sawdust. The results revealed that diatomite facilitated the conversion from NH 4 +-N to amino acid nitrogen and hydrolysis undefined nitrogen, then reduced NH 3 and N 2 O emission by 8.63–35.29% and 14.34–73.21%, respectively. Moreover, the structure and abundance of nitrogen functional genes provided evidence for nitrogen loss. Furthermore, compared with the control (0.03), the treatment blended with 10% diatomite (T3) had the highest value in composting score (-1.27). Additionally, the ratio of carbon and nitrogen (57.30%) was vital for reducing nitrogen loss among all physio-chemical parameters in this study. In conclusion, adding diatomite was a practical way to enhance nitrogen conservation and increase quality of end products, and the optimum added dosage was at 10%. [ABSTRACT FROM AUTHOR]

Black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae) biotreatment has been accepted as an eco-friendly alternative means for organic waste disposal; it can efficiently convert animal manure into biodiesel and biofertilizer. However, information about black soldier flies related to the organic matter transformation of different manures is limited. In this study, chicken manure (CM), pig manure (PM) and cow manure (COM) were treated by black soldier fly larvae for nine days, and the manures without black soldier fly larvae were noted as control. The dissolved organic matter (DOM) obtained from the initial and digested manures were studied by UV–vis, fluorescence, and Fourier transform infrared (FTIR) spectroscopy. The results showed that black soldier fly larvae decomposed the carboxylic, alcohol and aliphatic components in PM and CM, while they increased the carboxylic substances in COM. After black soldier fly digestion, the proteinaceous materials in all manures decreased, while the aromatic polycondensation, molecular weight and polar functional groups of DOM increased. Furthermore, according to analysis of the fluorescence spectra, the simple structural organic matter (5.99–29.50%) obviously decomposed and converted into the humic-like substances after black soldier fly digestion. Meanwhile, the humification degree of digested CM and COM (57.07–63.74%) are higher than that found in PM (42.45%). • Black soldier fly (BSF) changes the composition and structure of animal manures. • BSF decreased the proteinaceous materials and promoted the aromaticity of manure. • BSF increased the humic-like and fulvic-like substances in manures. • Cow manure and chicken manure were more prone to humification than pig manure. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of polyethylene (PE), polyvinyl chloride (PVC) and polyhydroxyalkanoate (PHA) microplastics on greenhouse gas and ammonia emissions during 60 days composting. PE, PVC and PHA microplastics were respectively mixed with the cow manure; and a treatment without microplastics was used as the control. Compared to the control, PE and PVC inhibited organic matter degradation. Conversely, PHA accelerated temperature increases and organic matter degradation. Meanwhile, PE and PHA aggravated CH 4 and NH 3 emissions by 7.9–9.1% and 20.9–33.9%, respectively. PVC decreased CH 4 and NH 3 emissions by 6.6% and 30.4%, respectively. Additionally, the N 2 O emissions of the PE and PVC treatments were higher than those of the control while PHA decreased N 2 O emissions by 11.8%. Furthermore, PE, PVC and PHA microplastics reduced the NO 3 −-N contents and compost maturity. The results indicated that microplastics reduced compost quality while the effects of microplastics on greenhouse gases and ammonia emissions were related to their sources. Unlabelled Image • Effect of microplastics on greenhouse gas and ammonia emissions were investigated. • PE and PHA aggravated CH 4 and NH 3 emissions, while PVC showed the adverse effect. • PE and PVC promote the N 2 O emissions, while PHA decreased 11.84% N 2 O emission. • PE, PVC and PHA microplastics obviously decreased the NO 3 −-N and compost maturity. [ABSTRACT FROM AUTHOR]

To evaluate the effect of clay on greenhouse gas (GHGs) emissions and humification during pig manure (PM) composting, two lab-scale composting experiments, a control and a 10% clay treatment, were established. The results showed that adding clay reduced the emissions of CH 4 and N 2 O by 45.88% and 86.79%, respectively, promoted the degradation of organic matter (OM) and facilitated the synthesis of humic acid (HA). The spectrum of dissolved organic matter (DOM) indicated that adding clay promoted the formation of aromatic carbon compounds and the degradation of aliphatic carbon. Furthermore, compared with the control, the spectral parameters including the specific UV absorbance at 254 nm (SUVA 254), the specific UV absorbance at 280 nm (SUVA 280) and the ration of the area at 435-480 nm and at 300-345 nm (A 4 /A 1) of DOM were increased by 5.45%, 3.66% and 29.26%, respectively. Combined with the excitation - emission matrix (EEM) and the percentage fluorescence response (Pi,n), the clay amendment promoted the decomposition of tyrosine and Tryptophan and the formation of humic-like substances, and thus increased humification. The variation in the HA/fulvic acid and the humification index confirmed these results. Therefore, clay amendment is beneficial for reducing GHG emissions, promoting humification and aromatization during pig manure composting. Unlabelled Image • Clay was applied into mixture of pig manure and sawdust for composting. • Clay prolonged thermophilic phase and promoted the degradation of organic matter. • Adding clay reduced the emission of CH 4 and N 2 O. • Clay stimulated the formation of aromatic-carbon and improved the humification. • Adding clay increased the humic acid/fulvic acid ratio and humification index. [ABSTRACT FROM AUTHOR]

• Black Tourmaline (TM) were added into pig manure and sawdust for composting. • Maximum value of HA/FA was observed in 10% TM added treatment. • TM promoted the transformation from NH 4 +-N to amino organic nitrogen. • 10% TM added treatment had the minimal nitrogen loss caused by NH 3 and N 2 O. • Total organic carbon was main factor driving changes of enzymatic activities. This study aimed to reveal the role of Black Tourmaline (TM) in the humification enhancement and the mechanism of nitrogen transformation during pig manure composting. Results showed that adding TM promoted the maturity and improved the humification degree by 20.13–33.77%. And TM was beneficial for the transformation from NH 4 +-N to amino organic nitrogen to fix more nitrogen in compost mass. Then NH 3 and N 2 O volatilization were decreased by 22.88–34.76% and 69.79–87.47% by comparison with the control, and the minimum value in nitrogen loss (26.78%) was observed in the 10% TM blended treatment. Furthermore, through RDA analysis, the protease an upmost contributor to nitrogen transformation. Meanwhile, total organic carbon was dominant factor affected enzymatic activities. Therefore, 10% TM was suggested to reduce nitrogen loss and increase humification in this research. Deeply related research in gene and specific addition amounts of TM will be investigated later. [ABSTRACT FROM AUTHOR]

Aiming to provide a highly-valuable green fertilizer, the effects of tertiary-amine bentonite on the carbon transformation and global warming potential were investigated during composting. TAB in weight ratios of 0%, 2%, 4%, 6%, 8% and 10% was mixed with CM and WS and composted for 50 days, respectively. The results showed that adding TAB promoted the degradation of TOC and DOC. With an increase in TAB amounts, HA content and polymerization were elevated by 11.71–27.08% and 3.40–47.00%, which was also supported by investigation of spectral parameters including SUVA 254 , SUVA 280 , A 4 /A 1 , and A 363-500. TAB benefited the CO 2 emission while reducing the volatilization of CH 4 and N 2 O, and the lowest global warming potential value was 108.99 in the 10% TAB treatment. TAB is considered as an economic amendment for improving CM composting process and quality in suggested amounts of 4%–10% based on humic-substance variations, spectral profiles of DOC, and global warming potential as well as the natural characterizations of TAB. Image 102 • Tertiary-amine bentonite (TAB) could promote the degradation of organic carbon. • The TAB could improve organic matter humification as well as compost maturity. • The TAB addition promoted aromatization by spectral parameters analysis. • The treatment with 10% TAB had a lowest value on greenhouse gas equivalent. [ABSTRACT FROM AUTHOR]

• Diatomite added to manure composting promoted the organic matter transformation. • Diatomite improved nitrogen conservation and increased quality of compost. • Adding Diatomite amendment reduced CH 4 and N 2 O emission. • Diatomite shortened the period of maturity reflected by germination index. In order to investigate the improvement of Diatomite (DM) on the production of cleaner composting, reflected by emission of NH 3 and greenhouse gases (GHGs), three dosages of DM (0%, 5% and 10%) were added into mixture of pig manure and sawdust for 42 days composting. Addition of DM promoted the transformation of organic matter and improved the quality of end product. Meanwhile, it was confirmed by the increase of NO 3 −-N formation and nitrogen conservation. Besides, adding DM aided on reducing emission of CH 4 , N 2 O and NH 3 by 18.27%−30.41%, 26.89%−84.16% and 10.41%−23.70%, respectively. Furthermore, the DM had a positive effect on the maturity of compost products, reflecting by GI value and HA/FA. Consequently, through the factor analysis, 10% was suggested to improve the quality of end product and reduce nitrogen loss as well as GHGs emission. [ABSTRACT FROM AUTHOR]

The effect of enhancing wood vinegar (WV) with a mixture of biochar (B) and zeolite (Z) to compost pig manure (PM) in a 130 L reactor was evaluated to determine the levels of greenhouse gas (GHG) and ammonia emissions. Six treatments were prepared in a 2:1 ratio of PM mixed with wheat straw (WS; dry weight basis): PM + WS (control), PM + WS + 10%B, PM + WS + 10%B + 10%Z, and PM + WS with 0.5%, 1.0% and 2.0%WV combined with 10%B + 10%Z. These were composted for 50 days, and the results indicated that the combined use of B, Z, and WV could shorten the thermophilic phase and improve the maturity of compost compared to the control treatment. In addition, WV mixed with B and Z could reduce ammonia loss by 64.45–74.32% and decrease CO 2 , CH 4 , and N 2 O emissions by 33.90–46.98%, 50.39–61.15%, and 79.51–81.10%, respectively. Furthermore, compared to treatments in which B and B + Z were added, adding WV was more efficient to reduce the nitrogen and carbon loss, and the 10%B + 10%Z + 2%WV treatment presented the lowest loss of carbon (9.16%) and nitrogen (0.75%). Based on the maturity indexes used, nitrogen conservation, and efficiency of GHG emissions reduction, the treatment 10%B + 10%Z + 2%WV is suggested for efficient PM composting. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effect of different concentrations (0%, 2.5%, 5.0%, 7.5% and 10.0%) of medical stone (MS) on the lignocellulose degradation and organic matter humification during pig manure (PM) composting. The results indicated that the addition of MS drastically promoted the organic carbon and lignin degradation. Compared to the control, the decomposition rate of hemicellulose and cellulose was increased by 9.64–27.08% and 2.11–12.07% in MS added treatments. Meanwhile, MS amendment significantly improved the humification of composting process, and the humic acid contents in MS added treatments were 5.58–9.75% higher than control. The FTIR and synchronous fluorescence spectra indicated that the aromatization of final compost was promoted with increasing the MS amount. In addition, the application of MS blended composts could significantly improve the biomass and chlorophyll content of pachoi ( Brassica chinensis L.). Due to the effective performance of MS, the 10.0% MS was suggested for PM composting. [ABSTRACT FROM AUTHOR]

The objective of the present study was to mitigate the greenhouse gas (GHG) emissions during composting of dewatered fresh sewage sludge (DFSS) employing biochar combined with zeolite (B + Z) and low dosage of lime (B + L). The 12% biochar was mixed at a 10%, 15% and 30% of zeolite and 1% lime, while without any additives was used as control. The results indicated that the combine use of B + Z was significantly increased the enzymatic activities and reduced the ammonia loss 58.03–65.17% as compare to B + L amended treatment, while CH 4 92.85–95.34% and N 2 O 95.14–97.28% decreased than control. The B + L1% amendment significantly increased the organic matter degradation but the reduction was lower than B + Z and that could reduce the CH 4 and N 2 O emission by 55.17–63.08% and 62.24–65.53% as compare to control, respectively. Overall our results demonstrated that 12%B + Z10% addition into DFSS can be potentially used to improve the DFSS composting by mitigation of GHG emission and nitrogen loss. [ABSTRACT FROM AUTHOR]

Greenhouse gases (GHGs) and ammonia (NH 3) are the main gas pollutants emitted during composting. This study used boric acid (H 3 BO 3) as an additive to simultaneously mitigate GHG and NH 3 emissions during composting and produce boron-rich organic fertilizer. The results showed that high dose of boric acid (1425 mg/kg) simultaneously reduced carbon dioxide (16.4%), methane (97.0%), nitrous oxide (91.7%), and NH 3 (27.1%) emissions in the composting process, resulting in the lowest carbon and nitrogen losses and global warming potential. However, low doses of boric acid (75 and 375 mg/kg) promoted nitrous oxide emissions and had limited emission reduction effects on other gases. Pearson correlation analysis showed that Corynebacterium, Planococcus, norank_f_MWH-CFBk5, Ruminofilibacter , norank_o_Actinomarinales and Truepera are key bacterial genera strongly associated with gas emissions. The results of principal co-ordinates analysis, network analysis, and structural equation modeling collectively indicated that the high dose of boric acid mitigates GHG and NH 3 emissions by undergoing chemical reactions, altering physicochemical properties, and reshaping bacterial communities. This study provides an innovative approach for synchronously mitigating GHG and NH 3 emissions and producing high value-added boron-rich organic fertilizer. [Display omitted] • High dose of boric acid (BA) reduced nitrous oxide (92%) and ammonia (27%) emissions. • High dose of BA reduced methane (97%) and carbon dioxide (16%) emissions. • High dose of BA reshaped the bacterial community during composting. • The key bacterial genera associated with gas emissions were identified. • This study provides a novel approach for producing boron-rich organic fertilizer. [ABSTRACT FROM AUTHOR]

• Adding bean dregs (BD) promotes decomposition and humification of compost. • Asses the maturity and stability of composting with BD amendment. • Choose an appropriate ratio of BD for improving compost quality. The purpose of this study was to effectively dispose of bean dregs (BD) using composting technology, which could provide a theoretical basis for the disposal of BD. Therefore, the influence of different quantities of bean dregs (BD) (0%, 5%, 10% and 15%, w/w with a dry base of pig manure (PM)) on the decomposition and humification of organic matter during PM-composting was investigated, and a 0% BD amendment was used as the control (CK). Wheat straw was used as a bulking agent. Compared to the CK, the BD amendment promoted the degradation of organic matter. The degree of organic matter degradation increased by 16.46–25.04% upon BD amendment. Furthermore, the BD amendment improved humification and increased indices of the humification ratio (HR), percentage of humic acids (PHA), degree of polymerization (DP) and the humification index (HI). Furthermore, Fourier transform infrared (FTIR) spectroscopy indicated that the aromatic structure was enhanced with the BD amendment, and excitation-emission matrix (EEM) fluorescence spectra showed increased humic-like substance production. Additionally, the dissolved organic carbon (DOC), germination index (GI), electrical conductivity (Ec) and carbon/nitrogen (C/N) influenced the maturity and stability of composting. Comparatively, a 10% BD addition showed the optimal performance among all PM-composting treatments. [ABSTRACT FROM AUTHOR]

• Applied Bean dregs (BD) in pig manure composting generated high quality product. • The total nitrogen content was the highest in 10%BD amended. • 10%BD was the optimum in promoting the diversity and abundance of bacteria. • 10%BD improved the activity of Firmicutes. This work studied the nitrogen transformation and bacterial dynamics in the co-composting of bean dregs (BD) and pig manure (PM). Four treatments were performed with BD at 0% (CK), 5%, 10% and 15% (w/w dry basis of PM) amended for 49-days aerobic compost. Results revealed that the temperature, NH 4 +-N and pH of end product all met the maturity requirement. The BD-amendment increased nitrogen losses (8.55%–55.92%) during composting compared to CK. However, this amendment also enhanced total nitrogen content (TKN) of end products (1.86%–12%). The highest content of TKN was in 10%BD-amended treatment with relatively lower nitrogen loss compared to 15%BD. Furthermore, the results of 16S rDNA showed that BD-amended changed the bacterial community composition compared with CK. Especially, 10%BD-amended was the optimum in promoting the diversity and abundance of bacteria. Additionally, Firmicutes , Actinobacteria, Proteobacteria, Bacteroidetes and Chloroflexi were dominant phyla and Bacilli was dominant class in BD-amended compost. [ABSTRACT FROM AUTHOR]

Highlights • Clay amendment on abundance of ARGs in poultry manure compost was studied. • ARGs abundance in 4% clay was significantly lower than higher dosage of clay. • 4% clay addition shows significant correlation between ARGs and temperature. • Clay addition is an effective approach to reduce the ARGs in compost. Abstract In this paper, the influence of clay amendment on antibiotic resistance genes (ARGs) fate and their relation with bacterial diversity in poultry manure (PM) composting was evaluated. The results confirmed that 4% clay amendment was significantly reduce the relative abundances (RAs) 94% of ARGs, while higher dosage of clay blended treatments (T5 and T6) composts were observed relatively very high percentage of ARGs as compared to other clay blended treatments. Clay addition play potential role on the occurrence and distribution of ARGs during the composting by altering the overall RAs of Firmicutes and Proteobacteria , and there host bacterial species. The heat map correlation figure also indicated that reduction of ARGs was significantly associated with the alteration of microbial dynamics and physicochemical parameters during the composting. Therefore, the addition of 4% clay in to PM composting system could efficiently mitigate the greater concentration of ARGs in PM compost and also environmental risk associated with its application. [ABSTRACT FROM AUTHOR]

Highlights • Biochar combined with enriched cultures addition in cow manure composting was studied. • Bacteria diversity and abundance remarkably enhanced in composting. • 12%WSB with bacteria culture treatment has maximum abundance of Firmicutes phyla. • Bacteroidales, Flavobacteriales and Bacilli were significantly higher abundance. Abstract The present work studied to evaluate the effectiveness under the interaction of bacterial consortium and biochar applied to give impetus to bacterial community activities among cow manure composting. High-throughput sequencing technique and six treatments were carried out: T2, T3 and T6 were single apply of bacteria culture (C), 12%wood biochar (12%WB) and 12%wheat straw biochar (12%WSB), respectively, while T4 and T5 were bacterial consortium combined with 12%WB and 12%WSB respectively, and T1 was used as control. The conclusion shows that the richness of bacterial community were most prosperity in T5 and T4 that in line with the statistical analysis angle of curves and cluster. The dominate phyla of Firmicutes, Proteobacteria and Bacteroidetes were accounted to 31.36%, 34.79% and 33.85%, the superior genera were Dysgonomonas (16.55%) , Empedobater (9.39%) , Atopostipes (13.42%) , Tissierella (8.25%) , Marinimicrobium (14.45%) and Pseudomonas (9%). Overall, bacterial consortium combined with biochar could stimulate microbe activity to accelerate degradation, enhance richness and alter specific selection of bacterial community. [ABSTRACT FROM AUTHOR]

Highlights • Wheat straw biochar addition effectively influence the fungal dynamic. • Fungal diversity analogous but relative abundance distinct variable during compost. • Batrachochytrium was potential host fungal genus in poultry manure compost. • Fungal and environmental elements interactions determined via Heat map illustrator. Abstract The fungal dynamics and its correlation with physicochemical and gaseous emission were investigated using metagenomics and Heat map illustrator (HEMI). Five different concentrations of wheat straw biochar (WSB) were applied to poultry manure (PM) and composted for 50 days; those without the WSB treatment were used as a control. The results revealed the dominant phyla to be Chytridiomycota , Mucoromycota , Ascomycota and Basidiomycota , while Batrachochytrium , Rhizophagus, Mucor, and Puccinia were the superior genera. In particular, the diversity of Chytridiomycota and Ascomycota was more abundant among all of the treatments. Overall, the diversity of the fungal species was correspondent, but relative abundance varied significantly among all of the composts. Principle Coordinate Analysis (PCoA) and Non-Metric Multi- Dimensional Scaling (NMDS) indicated that different concentrations of WSB applied treatments have significantly distinct fungal communities. In addition, correlation analyses of fungal interactions with environmental elements via HEMI also indicate a clear difference among the treatments. Ultimately, the relative abundance of fungal composition significantly influenced the PM compost treated by the WSB. [ABSTRACT FROM AUTHOR]

In this paper study the feasibility of Calcium-bentonite (Ca-B) combined with biochar (B) as an effective amendment for the co-composting of dewatered fresh sewage sludge (DFSS) mixed with wheat straw (WS), focusing on mitigation of greenhouse gases (GHG) emission and nutrients loss. The 12%B mixed with three different concentration of Ca-B (2%, 4% and 10%) was supplemented into 1:1 ratio mixture of DFSS and WS (dry weight basis), while compared with a 12%B alone and control or without any amended treatments. This experiment lasted for 42 days in a 130-L reactor. The CH 4 and N 2 O emission profiles were clearly indicated that 12%B alone and 12%B + Ca-B addition effectively buffered the composting mass and enhanced the rate of organic matter mineralization as compared to control treatment. Among the all treatments, minimum TOC (16.83%), TKN (0.38%) and dry matter (29.73%) losses were observed in 12%B+4%Ca-B applied treatment; and also improved compost quality compared to control. Furthermore, 12%B+4%Ca-B amendment was beneficial to the efficient organic matter degradation and low quantity of total GHG production from the feedstock without inhibition to composting compared with control treatment. Therefore, 12%B+4%Ca-B amendment is a promising ecofriendly solution for DFSS co-composting because it contributes to reduce the total GHG emission and produced matured compost with sound management of DFSS in China. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effects of biochar on greenhouse gas and microplastics mitigation were investigated. • Manure biochar reduced the global warming potential during sludge composting. • Sawdust biochar and manure biochar have better performance on microplastics reduction. • Biochar could promote small-sized microplastics (10-100 μm) degradation. • Biochar-regulated specific microbes to mitigate greenhouse gas and microplastics. This study aimed to investigate the effects of biochar derived from different sources (wheat straw, sawdust and pig manure) on greenhouse gas and microplastics (MPs) mitigation during sewage sludge composting. Compared to the control, all biochar significantly reduced the N 2 O by 28.91–41.23%, while having no apparent effect on CH 4. Sawdust biochar and pig manure biochar significantly reduced the NH 3 by 12.53–23.53%. Adding biochar decreased the global warming potential during composting, especially pig manure biochar (177.48 g/kg CO 2 -eq.). The concentration of MPs significantly increased in the control (43736.86 particles/kg) compared to the initial mixtures, while the addition of biochar promoted the oxidation and degradation of MPs (15896.06–23225.11 particles/kg), with sawdust biochar and manure biochar were more effective. Additionally, biochar significantly reduced the abundance of small-sized (10–100 μm) MPs compared to the control. Moreover, biochar might regulate specific microbes (e.g., Thermobifida , Bacillus and Ureibacillus) to mitigate greenhouse gas emissions and MPs degradation. [ABSTRACT FROM AUTHOR]

In this study, the bacterial community succession and variations were investigated in poultry manure (PM) compost by the using high-throughput sequencing in six different concentration of clay [at 0% (T1), 2% (T2), 4% (T3), 6% (T4), 8% (T5) and 10% (T6) on PM dry weight basis] applied compost. The results indicated that dominant phylum were Firmicutes , Proteobacteria , Actinobacteria and Bacteroidetes , while Bacillus , Paenibacillus , Virgibacillus , Oceanobacillus and Clostridium were the dominant genera in all the treatments. Correlation analyses provided useful tools for insight into the bacterial interactions with environmental factors and also extension of the compost maturation and resistance of bacteria. During the course of study, the diversity of bacteria similar but relative abundance variable in each treatments. However, the average and the normalized (to bacterial RAs or copies of sequences) both remained greater in higher dosage of clay applied treatments. Finally, the RAs of various bacterial community composition was affected in PM compost by the clay application. [ABSTRACT FROM AUTHOR]

In this study, the co-composting performance of Zn-rich antibiotic manufacturing wastes (AMW) and pig manure (PM) was evaluated. Four treatments, representing 2.5%, 5%, 10% and 20% of AMW (of PM dry weight) and control without AMW, were established during composting. Results suggested that the temperature, pH, electrical conductivity, NH 4 + -N and germination index in end product met the maturity and sanitation requirement. More than 99% of residual antibiotic was removed. Compared with PM composting alone, the cumulative CH 4 and N 2 O emissions in AMW composting increased by 13.46–79.00% and 10.78–65.12%, respectively. While the higher mixing ratios of AMW (10% and 20%) presented a negative impact on composing by inhibiting organic matter (OM) degradation and higher NH 3 emissions. The AMW had highly bioavailable Zn, but the exchangeable faction of Zn significantly decreased with the composting progress. [ABSTRACT FROM AUTHOR]

To assess the impact of clay as additive on compost maturity and reduction of greenhouse gases (GHGs) as well as ammonia emission during chicken manure composting. Six treatments with different dosages of clay (0%, 2%, 4%, 6%, 8% and 10% clay added by dry weight basis of chicken manure and wheat straw) were designed to conduct an aerobic composting experiment for 50 days. The results showed that the clay amendment could prolong the thermophilic phase and reduced the maturity period of composting. In addition, the GHGs (N 2 O and CH 4 ) and ammonia emission of clay added treatments were reduced by 25.3–63.4%, 26.01–50.24% and 8.5–70.5%, respectively. But CO 2 emission was significantly higher in 10% clay amended treatment. Furthermore, the redundancy analysis showed that C/N ratio and total organic matter among all physiochemical properties had significant relationship with GHGs and ammonia emission. Therefore, this study shown that clay addition can promote maturity, reduced GHGs emission and improve the quality of product. [ABSTRACT FROM AUTHOR]

This research was conducted to evaluate the effect of medical stone (MS) on the dissolved organic matter (DOM) extracted from composted pig manure (PM). Five treatments with different MS amounts (0%, 2.5%, 5%, 7.5% and 10% of PM by dry weight) were mixed with the initial feedstock and composted for 60 days. DOM was extracted from the composted materials and characterized using spectroscopic techniques, including UV–visible, Fourier transform infrared (FTIR) and fluorescence spectroscopy. The results showed that the addition of MS improved the biodegradation of protein-like materials, ether, alcohols, and polysaccharides. Compared to the control, the ratios of FTIR spectra peaks (1645 cm −1 /1407 cm −1 , 1645 cm −1 /2930 cm −1 , and 1645 cm −1 /1003 cm −1 ) in treatments in which MS was added were higher, and the peak ratio (1645 cm −1 /1103 cm −1 ) was increased by 4.54%–10.22%. Adding MS could also increase the SUVA 254 and SUVA 280 values while decreasing the E 250 /E 365 ratio, which indicates that the addition of MS increases aromaticity and molecular weight of the compost as well as humic-like compounds. Furthermore, the addition of MS improved the efficiency of the composting process and the rate of humification. The P i , n of region V in the MS amended treatments (53.86%–56.66%) was higher than in the control (52.17%), and 10% MS addition yielded the highest value. Overall, the results show that the addition of 10% MS to PM is beneficial to the composting process. [ABSTRACT FROM AUTHOR]

This study was aimed to examine the response of Ca-bentonite (CB) amendment to improve the sewage sludge (SS) composting along with wheat straw (WS) as bulking agent. Five treatments (SS + WS) were mixed with or without blending of discrepant concentration of CB (2%, 4%, 6%, and 10%), respectively, and without CB added treatment applied as the control. The results showed that compared to control and 2%CB blended treatments, while the 6–10%CB -amended treatment indicated maximum enzymatic activities with the composting progress and highest organic matter degradation and loss. The amendment of 6–10%CB increased the humic acid, HA/FA ratio, DON, NH 4 + -N, NO 3 and DOC but reduced the fulvic acids content and the maturity period by 2 weeks as compared to control. In addition, maturity parameters also confirmed that the highest seed germination was observed with the 10%CB applied compost followed by 6%CB, 4%CB and 2%CB applied treatments, respectively. [ABSTRACT FROM AUTHOR]

In this work, the influence of composting on the thermal decomposition behavior and decomposition kinetics of pig manure-derived solid wastes was analyzed using thermogravimetry. Wheat straw, biochar, zeolite, and wood vinegar were added to pig manure during composting. The composting was done in the 130 L PVC reactors with 100 L effective volume for 50 days. The activation energy of pyrolysis of samples before and after composting was calculated using Friedman’s method, while the pre-exponential factor was calculated using Kissinger’s equation. It was observed that composting decreased the volatile content of all the samples. The additives when added together in pig manure lead to a reduction in the activation energy of decomposition, advocating the presence of simpler compounds in the compost material in comparison with the complex feedstock. [ABSTRACT FROM AUTHOR]

The impact of biochar amendment on volatile fatty acids (VFAs) and odor generation during the biosolids-wheat straw composting was investigated. Five treatments were design using the same mixture of biosolids-wheat straw with different dosage of biochar blending (2%, 4%, 8% and 12% on dry weight basis) and without biochar applied treatment served as control. The results of VFAs and Odour Index (OI) profile designated that compost with 8–12% biochar became more rapidly humified with less quantity of VFAs and OI generation content compared to control. Consequently, the VFAs degrading and total bacterial abundance are also significantly higher recorded in 8–12% biochar than 2% biochar and control. In addition, 8–12% biochar applied treatment has significantly maximum close correlation among the all physicochemical and gaseous emission parameters. Finally, results designated that higher dosage of biochar (8–12% biochar) was more feasible approach for biosolids composting. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the feasibility of medical stone (MS) on microbial biomass, bacteria genes copy numbers, mitigation of gaseous emissions and its correlation with analyzed parameters during the biosolids composting. Composting of the biosolids by amendment of MS 0%, 2%, 4%, 6% and 10% (on dry weight basis) was performed using a 130-L composting reactor. The results showed that with increasing the dosage of MS, the CH 4 , N 2 O and NH 3 emission were reduced by 60.5–88.3%, 46.6–82.4% and 38.2–78.5%, respectively. In addition, the 6–10% MS amendment enhanced the organic waste mineralization and prolonged the thermophilic phase. The abundance of ammonia oxidizing bacteria (AOB) and archaea (AOAB) were decreased during the first 28 days, but considerable increment was observed during the maturation phase which indicated that AOB and AOAB were liable for nitrification during the curing phase of composting. A significant correlation was observed among the all analyzed parameters in 6–10% MS blended treatments. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify the effect of mixture of additives to improve the enzymatic activities, organic matter humification and diminished the bioavailability of heavy metals (HMs) during biosolids co-composting. In this study, zeolite (Z) (10%, 15% and 30%) with 1%lime (L) (dry weight basis of biosolids) was blended into the mixture of biosolids and wheat straw, respectively. The without any amendment and 1%lime applied treatments were run for comparison (Control). The Z + L addition resulted rapid organic matter degradation and humification with maximum enzymatic activities. In addition, higher dosage of Z + 1%L amendment reduced the bioavailability of HMs (Cu and Zn) and improved the end product quality as compared to control and 1%L applied treatments. However, the 30%Z + 1%L applied treatment showed maximum humification and low bioavailability of HMs but considering the economic feasibility and compost quality results, the treatment with 10%Z + 1%L is recommended for biosolids co-composting. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the bacterial and fungal diversities of 18contrastivecomposts applied with 17 different sources mad biochars applied treatments using 16S rRNA and 18S rDNA technology, while T-1 used as a control. The results showed that bacterial species of the phyla Actinobacteria , Proteobacteria and Chloroflexi , and fungi of the phylum Ascomycota and Basidiomycota were pre-dominant among the all treatments. The bacterial genus Subgroup_6_norank, Nocardioides , Pseudonocardia , Sphingomonas , Solirubrobacter and RB41_norank are first time identified in composting ecosystem. In addition, the fungal genus Ascomycota _unclassified, Aspergillus , Penicillium , Pleosporales _unclassified and Herpotrichlellacease _unclassified ubiquitous among the all compost. The Shannon and refraction-curve biodiversity indices showed a clear heterogeneity among all the treatments, which could be due to isolation of new genera in this system. Finally, the principal component analysis of the relative number of sequences also confirmed that bacterial and fungal population indiscriminate in different sources mad biochar applied treatments. [ABSTRACT FROM AUTHOR]