Unraveling the role of black soldier fly larvae in chicken manure conversion: Facilitating maturation and enhancing humification.

Black soldier fly larvae (BSFL) have garnered considerable attention for their efficacy in mitigating waste management challenges. However, their potential in treating antibiotics contaminated chicken manure remains uncertain. This study investigates the physicochemical properties changes and nutrient dynamics during the composting of contaminated-chicken manure using BSFL. The results indicate that BSFL treatment reduces electrical conductivity (by 6.01-58.09 %), organic matter, and dissolved organic carbon content in chicken manure throughout the composting process, while maintaining a more stable pH value (pH âˆ¼ 6.0-8.0). This is attributed to the consumption of organic matter by BSFL and the subsequent promotion of organic acid formation. Additionally, BSFL treatment improves the degree of aromatization of dissolved organic matter (DOM) in chicken manure and increases the proportions of fulvic acid (up to 48.77 %) and humic acid (maximally 14.27 %) within the DOM. The germination index and pot experiments indicated improved compost maturity and plant growth in BSFL-treated composts. Furthermore, BSFL meal demonstrated high protein and essential fatty acid content, highlighting its potential as a protein supplement in animal feed. This study underscores the efficacy of BSFL in enhancing compost quality and nutrient availability, offering a sustainable solution for waste management and animal feed production.

The IncC and IncX1 resistance plasmids present in multi-drug resistant Escherichia coli strains isolated from poultry manure in Poland.

The study describes the whole-genome sequencing of two antibiotic-resistant representative Escherichia coli strains, isolated from poultry manure in 2020. The samples were obtained from a commercial chicken meat production facility in Poland. The antibiotic resistance profile was characterized by co-resistance to ß-lactam antibiotics, aminoglycosides, and fluoroquinolones. The three identified resistance plasmids (R-plasmids), pECmdr13.2, pECmdr13.3, and pECmdr14.1, harbored various genes conferring resistance to tetracyclines (tetR[A]) for, aminoglycoside (aph, aac, and aad families), ß-lactam (blaCMY-2, blaTEM-176), sulfonamide (sul1, sul2), fluoroquinolone (qnrS1), and phenicol (floR). These plasmids, which have not been previously reported in Poland, were found to carry IS26 insertion elements, the intI1-integrase gene, and conjugal transfer genes, facilitating horizontal gene transfer. Plasmids pECmdr13.2 and pECmdr14.1 also possessed a mercury resistance gene operon related to transposon Tn6196; this promotes plasmid persistence even without antibiotic selection pressure due to co-selection mechanisms such as co-resistance. The chicken manure-derived plasmids belonged to the IncX1 (narrow host range) and IncC (broad host range) incompatibility groups. Similar plasmids have been identified in various environments, clinical isolates, and farm animals, including cattle, swine, and poultry. This study holds significant importance for the One Health approach, as it highlights the potential for antibiotic-resistant bacteria from livestock and food sources, particularly E. coli, to transfer through the food chain to humans and vice versa.

The production of methyl mercaptan is the main odor source of chicken manure treated with a vertical aerobic fermenter.

The process of harmless treatment of livestock manure produces a large amount of odor, which poses a potential threat to human and livestock health. A vertical fermentation tank system is commonly used for the environmentally sound treatment of chicken manure in China, but the composition and concentration of the odor produced and the factors affecting odor emissions remain unclear. In this study, we investigated the types and concentrations of odors produced in the mixing room (MR), vertical fermenter (VF), and aging room (AR) of the system, and analyzed the effects of bacterial communities and metabolic genes on odor production. The results revealed that 34, 26 and 26 odors were detected in the VF, MR and AR, respectively. The total odor concentration in the VF was 66613 ± 10097, which was significantly greater than that in the MR (1157 ± 675) and AR (1143 ± 1005) (P < 0.001), suggesting that the VF was the main source of odor in the vertical fermentation tank system. Methyl mercaptan had the greatest contribution to the odor produced by VF, reaching 47.82%, and the concentration was 0.6145 ± 0.2164 mg/m3. The abundance of metabolic genes did not correlate significantly with odor production, but PICRUSt analysis showed that cysteine and methionine metabolism involved in methyl mercaptan production was significantly more enriched in MR and VF than in AR. Bacillus was the most abundant genus in the VF, with a relative abundance significantly greater than that in the MR (P < 0.05). The RDA results revealed that Bacillus was significantly and positively correlated with methyl mercaptan. The use of large-scale aerobic fermentation systems to treat chicken manure needs to focused on the production of methyl mercaptan.

Enhancement of Biodegradability of Chicken Manure via the Addition of Zeolite in a Two-Stage Dry Anaerobic Digestion Configuration.

Leach bed reactors (LBRs) are dry anaerobic systems that can handle feedstocks with high solid content, like chicken manure, with minimal water addition. In this study, the chicken manure was mixed with zeolite, a novel addition, and packed in the LBR to improve biogas production. The resulting leachate was then processed in a continuous stirred tank reactor (CSTR), where most of the methane was produced. The supernatant of the CSTR was returned to the LBR. The batch mode operation of the LBR led to a varying methane production rate (MPR) with a peak in the beginning of each batch cycle when the leachate was rich in organic matter. Comparing the MPR in both systems, the peaks in the zeolite system were higher and more acute than in the control system, which was under stress, as indicated by the acetate accumulation at 2328 mg L-1. Moreover, the presence of zeolite in the LBR played a crucial role, increasing the overall methane yield from 0.142 (control experiment) to 0.171 NL CH4 per g of volatile solids of chicken manure entering the system at a solid retention time of 14 d. Zeolite also improved the stability of the system. The ammonia concentration increased gradually due to the little water entering the system and reached 3220 mg L-1 (control system) and 2730 mg L-1 (zeolite system) at the end of the experiment. It seems that zeolite favored the accumulation of the ammonia at a lower rate (14.0 mg L-1 d-1) compared to the control experiment (17.3 mg L-1 d-1). The microbial analysis of the CSTR fed on the leachate from the LBR amended with zeolite showed a higher relative abundance of Methanosaeta (83.6%) compared to the control experiment (69.1%). Both CSTRs established significantly different bacterial profiles from the inoculum after 120 days of operation (p < 0.05). Regarding the archaeal communities, there were no significant statistical differences between the CSTRs and the inoculum (p > 0.05).

Co-pyrolysis of chicken manure with tree bark for reduced biochar toxicity and enhanced plant growth in Arabidopsis thaliana.

Co-pyrolysis of chicken manure with tree bark was investigated to mitigate salinity and potentially toxic element (PTE) concentrations of chicken manure-derived biochar. The effect of tree bark addition (0, 25, 50, 75 and 100 wt%) on the biochar composition, surface functional groups, PTEs and polycyclic aromatic hydrocarbons (PAH) concentration in the biochar was evaluated. Biochar-induced toxicity was assessed using an in-house plant growth assay with Arabidopsis thaliana. This study shows that PTE concentrations can be controlled through co-pyrolysis. More than 50 wt% of tree bark must be added to chicken manure to reduce the concentrations below the European Biochar Certificate-AGRO (EBC-AGRO) threshold. However, the amount of PAH does not show a trend with tree bark addition. Furthermore, co-pyrolysis biochar promotes plant growth at different application concentrations, whereas pure application of 100 wt% tree bark or chicken manure biochar results in decreased growth compared to the reference. In addition, increased plant stress was observed for 100 wt% chicken manure biochar. These data indicate that co-pyrolysis of chicken manure and tree bark produces EBC-AGRO-compliant biochar with the potential to stimulate plant growth. Further studies need to assess the effect of these biochars in long-term growth experiments.

Genome-centric metagenomics and methanogenic pathway analysis for acclimated anaerobic digestion of chicken manure with high ammonia stressed under thermophilic condition.

Thermophilic anaerobic digestion (AD) of animal manure offers various environmental benefits but the process requires a microbial community acclimatized to high ammonia. In current study, a lab-scale continuous stirred tank reactor (CSTR) fed with chicken manure was operated under thermophilic condition for 450 days in total. Results showed that the volumetric methane production decreased from 445 to 328 and sharply declined to 153 mL L-1·d-1 with feeding total solid (TS) step increased from 5% to 7.5% and 10%, respectively. While, after a long-term stop feeding for 80 days, highly disturbed reactor was able to recover methane generation to 739 mL L-1·d-1 at feeding TS of 10%. Isotope analysis indicted acetate converted to methane through the syntrophic acetate oxidation and hydrogenotrophic methanogenesis (SAO-HM) pathway increased from 33% to 63% as the concentration of ammonium increased from 2493 to 6258 mg L-1. Significant different in the genome expression of the SAO bacterial from 0.09% to 1.23%, combining with main hydrogenotrophic partners (Methanoculleus spp. and Methanothermobacter spp.) contented of 2.1% and 99.9% during inhibitory and recovery stages, respectively. The highly expressed KEGG pathway in level 3 (enzyme genes) for the Recovery sludge combining with the extraordinary high abundance of genera Halocella sp. suggested that Halocella sp. might be a highly efficient hydrolytic and acidogenic microorganism and enhance the process of SAO during carbon metabolic flow to methane. This report will be a basis for further study of AD studies on high nitrogen content of poultry manure.

Chicken manure-derived biochar enhanced the potential of Comamonas testosteroni ZG2 to remediate Cd contaminated soil.

The combined remediation of Cd-contaminated soil using biochar and microorganisms has a good application value. In this study, the effect of chicken manure-derived biochar on CdCO3 precipitation induced by Comamonas testosteroni ZG2 was investigated. The results showed that biochar could be used as the carrier of strain ZG2, enhance the resistance of strain ZG2 to Cd, and reduce the toxicity of Cd to bacterial cells. Cd adsorbed by biochar could be induced by strain ZG2 to form CdCO3 precipitation. Strain ZG2 could also induce CdCO3 precipitation when biochar was added during precipitation formation and fermentation broth formation. The CdCO3 precipitation could enter the pores of the biochar and attach to the surface of the biochar. The single and combined effects of strain ZG2 and biochar could realize the remediation of Cd-contaminated soil to a certain extent. The overall effect was in the order of strain ZG2 with biochar > biochar > strain ZG2. The combination of strain ZG2 and biochar reduced soil available Cd by 48.2%, the aboveground biomass of pakchoi increased by 72.1%, and the aboveground Cd content decreased by 73.3%. At the same time, it promoted the growth and development of the root system and improved the microbial community structure of the rhizosphere soil. The results indicated that chicken manure-derived biochar could enhance the stability of CdCO3 precipitation induced by strain ZG2, and strain ZG2 combined with biochar could achieve a more stable remediation effect on Cd-contaminated soil.

The biotic effects of lignite on humic acid components conversion during chicken manure composting.

Targeted regulation of composting to convert organic matter into humic acid (HA) holds significant importance in compost quality. Owing to its low carbon content, chicken manure compost often requires carbon supplements to promote the humification progress. The addition of lignite can increase HA content through biotic pathways, however, its structure was not explored. The Parallel factor analysis revealed that lignite can significantly increase the complexity of highly humified components. The lignite addition improved phenol oxidase activity, particularly laccase, during the thermophilic and cooling phases. The abundance and transformation functions of core bacteria also indicated that lignite addition can influence the activity of microbial transformation of HA components. The structural equation model further confirmed that lignite addition had a direct and indirect impact on enhancing the complexity of HA components through core bacteria and phenol oxidase. Therefore, lignite addition can improve HA structure complexity during composting through biotic pathways.

Co-composting sugar-containing waste with chicken manure-A new approach to carbon sequestration.

Improving resource use is a pressing research issue because of the huge potential organic waste market. Composting is a recycling technique, treatment to achieve the dual effect of resource recovery and zero waste. Waste composition varies: for example, chicken manure is rich in protein, straw contains wood fibres, fruit and vegetables contain sugar, and food waste contains starch. When considering combining waste streams for composting, it is important to ask if this approach can reduce overall composting costs while achieving a more concentrated result. Chicken manure, in particular, presents a unique challenge. This is due to its high protein content. The lack of precursor sugars for glucosamine condensation in chicken manure results in lower humus content in the final compost than other composting methods. To address this, we conducted experiments to investigate whether adding sugary fruits and vegetables to a chicken manure composting system would improve compost quality. To improve experimental results, we used sucrose and maltose instead of fruit and vegetable waste. Sugars added to chicken manure composting resulted in a significant increase in humic substance (HS) content, with improvements of 9.0% and 17.4%, respectively, compared to the control. Sucrose and maltose have a similar effect on the formation of humic substances. These results demonstrate the feasibility of composting fruit and vegetable waste with chicken manure, providing a theoretical basis for future composting experiments.

Potential of combined reactor and static composting applications for the removal of heavy metals and antibiotic resistance genes from chicken manure.

Chicken manure (CM) can pose a serious threat to environmental and human health, and need to be managed properly. The compost can effectively treat CM. However, there is limited research on the heavy metals and antibiotic resistance genes (ARGs) during compost CM. In this study, the combined application of reactor and static composting (RSC) was used to produce organic fertilizer of CM (OCM), and heavy metals, ARGs and bacterial community structure was investigated. The results show that RSC could be used to produce OCM, and OCM meet the National organic fertilizer standard (NY/T525-2021). Compared to the initial CM, DTPA-Cu, DTPA-Zn, DTPA-Pb, DTPA-Cr, DTPA-Ni and DTPA-As in OCM decreased by 40.83%, 23.73%, 34.27%, 38.62%, 16.26%, and 43.35%, respectively. RSC decreased the relative abundance of ARGs in CM by 84.06%, while the relative abundance of sul1 and ermC increased. In addition, the relative abundance and diversity of ARGs were mainly influenced by the bacterial community, with Actinobacteria, Firmicutes, and Proteobacteria becoming the dominant phyla during composting, and probably being the main carriers and dispersers of most of the ARGs. Network analyses confirmed that Gracilibacillus, Lactobacillus, Nocardiopsis, Mesorhizobium and Salinicoccus were the main potential hosts of ARGs, with the main potential hosts of sul1 and ermC being Mesorhizobium and Salinicoccus. The passivation and physicochemical properties of heavy metals contribute to the removal of ARGs, with sul1 and ermC being affected by the toal heavy metals. Application of RSC allows CM to produce mature, safe organic fertilizer after 32 d and reduces the risk of rebound from ARGs, but the issues of sul1 and ermC gene removal cannot be ignored.

Mitigating Tetracycline antibiotic contamination in chicken manure using ex situ fermentation system.

Excessive use of tetracycline antibiotics in poultry farming results in significant concentrations of these drugs and tetracycline resistance genes (TRGs) in chicken manure, impacting both environmental and human health. Our research represents the first investigation into the removal dynamics of chlortetracycline (CTC) and TRGs in different layers of an ex situ fermentation system (EFS) for chicken waste treatment. By pinpointing and analyzing dominant TRGs-harboring bacteria and their interactions with environmental variables, we've closed an existing knowledge gap. Findings revealed that CTC's degradation half-lives spanned 3.3-5.8 days across different EFS layers, and TRG removal efficiency ranged between 86.82% and 99.52%. Network analysis highlighted Proteobacteria and Actinobacteria's essential roles in TRGs elimination, whereas Chloroflexi broadened the potential TRG hosts in the lower layer. Physical and chemical conditions within the EFS influenced microbial community diversity, subsequently impacting TRGs and integrons. Importantly, our study reports that the middle EFS layer exhibited superior performance in eliminating CTC and key TRGs (tetW, tetG, and tetX) as well as intI2. Our work transcends immediate health and environmental remediation by offering insights that encourage sustainable agriculture practices.

Control of nitrogen and odor emissions during chicken manure composting with a carbon-based microbial inoculant and a biotrickling filter.

Although aerobic composting is usually utilized in livestock manure disposal, the emission of odorous gases from compost not only induces harm to the human body and the environment, but also causes loss of nitrogen, sulfur, and other essential elements, resulting in a decline in product quality. The impact of biotrickling filter (BTF) and insertion of carbon-based microbial agent (CBMA) on compost maturation, odor emissions, and microbial population during the chicken manure composting were assessed in the current experiment. Compared with the CK group, CBMA addition accelerated the increase in pile temperature (EG group reached maximum temperature 10 days earlier than CK group), increased compost maturation (GI showed the highest increase of 41.3% on day 14 in EG group), resulted in 36.59% and 14.60% increase in NO3--N content and the total nitrogen retention preservation rate after composting. The deodorization effect of biotrickling filter was stable, and the removal rates of NH3, H2S, and TVOCs reached more than 90%, 96%, and 56%, respectively. Furthermore, microbial sequencing showed that CBMA effectively changed the microbial community in compost, protected the ammonia-oxidizing microorganisms, and strengthened the nitrification of the compost. In addition, the nitrifying and denitrifying bacteria were more active in the cooling period than they were in the thermophilic period. Moreover, the abundance of denitrification genes containing nirS, nirK, and nosZ in EG group was lower than that in CK group. Thus, a large amount of nitrogen was retained under the combined drive of BTF and CBMA during composting. This study made significant contributions to our understanding of how to compost livestock manure while reducing releases of odors and raising compost quality.

Response of fulvic acid linking to redox characteristics on methane and short-chain fatty acids in anaerobic digestion of chicken manure.

Fulvic acids (FAs) is formed during the bioconversion of organic matter (OM) to biogas during anaerobic digestion (AD) and has a complex structure and redox function. However, the evolutionary mechanisms of FAs during AD and its interactions with acid and methane production have not been sufficiently investigated, especially at different stages of AD. Intermittent AD experiments by chicken manure and rice husk showed significant structural changes and reduced aromatization of FAs (e.g., O-H stretch6, 14.10-0%; SR, 0.22-0.60). The electron donating capacity (EDC) [9.76-45.39 µmole-/(g C)] and electron accepting capacity (EAC) [2.55-5.20 µmole-/(g C)] of FAs showed a tendency of decreasing and then increasing, and FAs had a stronger electron transfer capacity (ETC) in the methanogenic stage. Correlation analysis showed that the EDC of FAs was influenced by their own structure (C-O stretch2, C-H bend1, C-H bend4, and N-H bend) and also had an inhibitory effect on propionic production, which further inhibited acetic production. The EAC of FAs was affected by molecular weight and had a promoting effect on methane production. Structural equation modelling identified three possible pathways for AD. The C-O stretch2 structure of FAs alone inhibits the production of propionic. In addition, pH can directly affect the EDC of FAs. This study provides a theoretical basis for the structural and functional evolution of FAs in AD of chicken manure on the mechanism of methane production.

Impact of biochar and organic fertilizers on sweet potato yield, quality, ascorbic acid, ß-carotene, sugars, and phenols contents.

The demand for food is increasing and the use of soil organic amendments in agricultural management practices has been instructed to increase crop yield and reduce dependence on synthetic inorganic fertilizers at low cost to limited resource farmers. However, the effect of organic amendments on the quality and nutritional composition of edible plants has received little attention. Locally available organic amendments (sewage sludge SS, chicken manure CM, cow manure Cow, vermicompost Vermi, and biochar Bio) were chosen to test their impact on field-grown sweet potato, Ipomoea batatas L. yield, root quality, and root nutritional composition. The results indicated that utilizing Cow manure in growing sweet potatoes significantly promoted root yield and root nutritional composition. Cow treatment produced the greatest number of roots compared to Bio, CM, SS, and the control treatments. The results also revealed that the concentrations of vitamin C (260. 3 µg g-1), ß-carotene (45.4 µg g-1), soluble sugars (16.7 mg g-1), and total phenols (196.3 3 µg g-1 fresh roots) were greater in the roots of plants grown in Cow compared to the roots of the control treatment. The results indicated the low impact of biochar whereas Cow is recommended for enhancing sweet potato yield and nutritional composition.

Struvite-Driven Integration for Enhanced Nutrient Recovery from Chicken Manure Digestate.

This study investigated the synergistic integration of clean technologies, specifically anaerobic digestion (AD) and struvite precipitation, to enhance nutrient recovery from chicken manure (CM). The batch experiments were conducted using (i) anaerobically digested CM digestate, referred to as raw sample (RS), (ii) filtered digestate sample (FS), and (iii) a synthetically prepared control sample (CS). The research findings demonstrated that the initial ammonia concentration variations did not significantly impact the struvite precipitation yield in the RS and FS, showcasing the materials inertness process's robustness to changing ammonia concentrations. Notably, the study revealed that the highest nitrogen (N) recovery, associated with 86% and 88% ammonia removal in the CS and FS, was achieved at pH 11, underscoring the efficiency of nutrient recovery. The RS achieved the highest nitrogen recovery efficiency at pH 10, at 86.3%. In addition, the research highlighted the positive impact of reducing heavy metal levels (Zn, Cu, Pb, Ni, Cd, Cr and Fe) and improving the composition of the microbial community in the digestate. These findings offer valuable insights into sustainable manure and nutrient management practices, emphasizing the potential benefits for the agricultural sector and the broader circular economy. Future research directions include economic viability assessments, regulatory compliance evaluations, and knowledge dissemination to promote the widespread adoption of these clean technologies on a larger scale. The study marks a significant step toward addressing the environmental concerns associated with poultry farming and underscores the potential of integrating clean technologies for a more sustainable agricultural future.

Production of bagasse fly ash-derived CO2 adsorbent by physical activation and by nitrogen-functionalization using hydrothermal treatment.

The high cost of commercial CO2 capture material is one of the issues hindering the widespread adaptation of the technology. This study explored efficient ways of utilizing waste material in the form of bagasse fly ash (BFA) as CO2 adsorbent through thermochemical preparations of physical activation, and hydrothermal carbonization (HTC). The activation of BFA using flue gas was able to produce an adsorbent with good CO2 adsorption capacity, with similar results to the CO2 activation. The second approach using co-HTC of BFA with chicken manure (CM) optimized using Box-Behnken design of experiment was able to produce an adsorbent with CO2 adsorption capacity nearly on-par with commercial adsorbents. It was also found that the model was able to accurately predict the experiment outcome when verified with the additional experiments. Material characterizations showed that the increase of the CO2 adsorption capacity of the adsorbent might have been achieved through the formation of secondary amines deposited on the BFA. The results of this study showed that the utilization of waste in the form of BFA and CM could contribute to the advancement of circular and low-cost CO2 capture medium from waste materials, which could increase the adaptation and involvement of sugar industry and poultry farm.

Change of core microorganisms and nitrogen conversion pathways in chicken manure composts by different substrates to reduce nitrogen losses.

Due to the rapid development of animal husbandry, the associated environmental problems cannot be ignored, with the management of livestock and poultry manure emerging as the most prominent issue. Composting technology has been widely used in livestock and poultry manure management. A deeper understanding of the nitrogen conversion process during composting offers a theoretical foundation for selecting compost substrates. In this study, the effects of sawdust (CK) and spent mushroom compost (T1) as auxiliary materials on nitrogen as well as microbial structure in the composting process when composted with chicken manure were investigated. At the end of composting, the nitrogen loss of T1 was reduced by 17.18% relative to CK. When used as a compost substrate, spent mushroom compost accelerates the succession of microbial communities within the compost pile and alters the core microbial communities within the microbial community. Bacterial genera capable of cellulose degradation (Fibrobacter, Herbinix) are new core microorganisms that influence the assimilation of nitrate reduction during compost maturation. Using spent mushroom compost as a composting substrate increased the enzyme activity of nitrogen assimilation while decreasing the enzyme activity of the denitrification pathway.

Adsorption characteristics and mechanisms of Cd(II) from wastewater by modified chicken manure biochar.

Due to the threat to food supply and human health posed by cadmium-contaminated wastewater, a highly effective adsorbent is under necessary development to remove cadmium from wastewater. In this study, four new types of modified biochars with different modifier concentrations were prepared from chicken manure using K2FeO4 as a modifier, and the modified biochar KFBC1 with the best adsorption effect was obtained through optimal experiments. Various characterization analyses have shown that KFBC1 has a rough surface structure, abundant pore structure, and a large number of functional groups. Additionally, iron oxides are introduced on the surface of the biochar, which provided a favorable condition for the adsorption of Cd(II) in wastewater. The adsorption performance of Cd(II) on the biochar before and after modification was investigated through batch adsorption experiments. The adsorption kinetic model of KFBC1 to Cd(II) in solution was in accordance with the quasi-secondary kinetic model, and the adsorption isothermal model was in accordance with the Langmuir model, with a maximum adsorption capacity of 330.06 mg/g, which was 5.15 fold of pristine BC. Meanwhile, the adsorption rate of Cd(II) by KFBC1 was positively correlated with dosage and pH. Pore adsorption, ion exchange, surface precipitation, interaction with -π electrons, and complexation of oxygen-containing functional groups on the surface were considered as important mechanisms for the removal of Cd(II) by KFBC1. According to the results, KFBC1 is a novel and efficient adsorbent that can be used as a treatment agent for cadmium-contaminated wastewater.

Effects of biochar combined with MgO desulfurization waste residue on nitrogen conversion and odor emission in chicken manure composting.

Aim: Chicken manure is known to produce strong odors during aerobic composting, which not only pollutes the surrounding environment but also leads to the loss of valuable nutrients like nitrogen and sulfur, thus reducing the quality of the fertilizer. Methods: In this study, we explored the use of biochar combined with MgO desulfurization waste residue (MDWR) as a novel composting additive. Our approach involved conducting composting tests, characterizing the compost samples, conducting pot experiments, and examining the impact of the additives on nitrogen retention, deodorization, and compost quality. Results: Our findings revealed that the addition of biochar and MDWR significantly reduced ammonia volatilization in chicken manure compost, demonstrating a reduction rate of up to 60.12%. Additionally, the emission of volatile organic compounds (VOCs) from chicken manure compost treated with biochar and MDWR decreased by 44.63% compared to the control group. Conclusions: The composting product treated with both biochar and MDWR (CMB) exhibited a 67.7% increase in total nitrogen (TN) compared to the blank control group, surpassing the other treatment groups and showcasing the synergistic effect of these two additives on nitrogen retention. Moreover, the CMB treatment facilitated the formation of struvite crystals. Furthermore, our pot experiment results demonstrated that the CMB treatment enhanced vegetable yield and quality while reducing nitrate content. These findings highlight the significant impact of MDWR on nitrogen retention, deodorization, and compost quality enhancement, thereby indicating its promising application prospects.

Wood biochar enhances methanogenesis in the anaerobic digestion of chicken manure under ammonia inhibition conditions.

The process of breaking down chicken manure through anaerobic digestion is an effective waste management technology. However, chicken manure can be a challenging feedstock, causing ammonia stress and digester instability. This study examined the impacts of adding wood biochar and acid-alkali-treated wood biochar to anaerobically digest chicken manure under conditions of ammonia inhibition. The results highlighted that only the addition of 5 % acid-alkali-treated wood biochar by volume can achieve cumulative methane production close to the typical methane potential range of chicken manure. The treated wood biochar also exhibited highest total ammonia nitrogen removal compared to the Control treatment. Scanning Electron Microscope revealed growing interactions between biochar and methanogens over time. Real-time polymerase chain reaction showed that treated wood biochar produced the highest number of bacterial biomass. In addition, 16S amplicon-based sequencing identified a more robust archaeal community from treated biochar addition. Overall, the acid-alkali treatment of biochar represents an effective method of modifying biochar to improve its performance in anaerobic digestion.