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.

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 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.

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.

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.

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.

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), β-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.

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.

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.

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.