This paper proposes a probabilistic health index-based method for estimating the apparent age of power transformer. Compared with the conventional weighted-score-sum based health index, the probabilistic health index is calculated as a data fusion result of kinds of transformer condition monitoring data through a constructed Bayesian belief network. The regression result of such a probabilistic health index is then applied to estimate the apparent age of the transformer through a few steps listed in the paper. The apparent age not only embodies an overall health status a transformer, but also helpful for sorting a transformer fleet based on the estimated apparent age or even make it easy to make comparisons between transformer fleets. The estimated apparent age can be taken as a reference for power utilities to prioritize transformers and pay attention to the unit who owns the maximum apparent age among a fleet, and thus helps to schedule replacement plans. Case studies with different transformers verify the usability and prove the advantages of the proposed method.

To improve the biogas potential in anaerobic digestion of cattle manure in cold regions, we investigated, in this study, the potential of the anaerobic digestion of cattle manure through sequencing batch anaerobic digestion experiments at sub-mesophilic temperatures (15°C, 20°C, 25°C, and 37°C) for 50 days. Specifically, the changes in the biogas yield, pH, sCOD concentration, enzyme activity, and microbial community structure were examined. The maximum daily yield of biogas was 19.18 mL·gVS ⁻¹ , which was recorded on day 6 at 37°C, and the final biogas accumulation yield at this temperature was 403.64 mL·gTS ⁻¹ . The concentration of sCOD gradually increased as enzyme activity increased. The maximum activities of cellulase, hemicellulase, protease, and amylase were recorded in the 37°C experimental group. The decrease in temperature severely limited the activity of different types of enzymes, resulting in a decrease in the activity of microorganisms, which greatly influenced the methanogenic reaction. The dominant bacteria at the phylum level were Bacteroidetes and Proteobacteria , and the dominant methanogen at the genus level was Methanosaeta .

Livestock and poultry waste liquid contains a lot of nitrogen, phosphorus, and microorganisms, and direct discharge causes great harm to the environment. Chicken manure was selected as the research object, and nanoparticle nano-Fe₂O₃, nano-C₆₀, antibiotics enrofloxacin, sulfamethoxazole, and oxytetracycin were selected as additives to carry out medium-temperature sequential batch anaerobic digestion experiment. The experiment lasted for 55 days. The results showed that (1) gas production reached its peak in the first 1–2 days of a single stress experiment, and the cumulative gas production in the first 10 days was as follows: R5 > R4 > R3 > R2 > CK > R1; (2) the concentrations of total volatile fatty acids (TVFAs) in the groups increased rapidly from day 1 to 10, and the concentrations of TVFAs in the nano-Fe₂O₃ and nano-C₆₀ groups were higher than those in the other four groups. The pH of the system decreased, and the soluble chemical oxygen demand (SCOD) was consistent with the trend of TVFAs, while the pH of the nanoparticle group was lower; (3) changes in the horizontal structure of bacterial community of Firmicutes and Bacteroidetes were dominant bacteria in each group on the first day. On day 5, the relative abundance of actinomycetes and Bacteroidetes increased significantly. This experiment contributes to the study of the effects of adding nanoparticles and antibiotics to anaerobic digestion substrates on gas production characteristics, provides data support, and characterizes the microbial situation during digestion. This paper can help to realize carbon emission reduction in agriculture and rural areas. Based on the above background, a self-designed system for testing the anaerobic digestion potential of methane was used in this study using chicken manure. Based on the single pollutant stresses of nano-Fe₂O₃, nano-C₆₀, enrofloxacin, sulfamethoxazole, and hygromycin, the effects of different pollutants under independent stresses on methane production and the changes in the performance of the anaerobic digestion system for gas production were investigated. The chemical parameters and microbial diversity in the anaerobic digestion process were analyzed, and the effects of different nanoparticles and antibiotics on the anaerobic system of chicken manure were elucidated. The results of the study can provide data support for the stable operation of biogas projects, which is of great significance in promoting the sustainable development of ecological agriculture.

Medium-temperature anaerobic digestion experiments lasting for 55 days were conducted using sulfamethoxazole (SMX)-containing chicken manure in sequential batch reactors added with nano-Fe ₂ O ₃ at a concentration of 300 mg·kg ⁻¹ ·TS or nano-C ₆₀ at a concentration of 100 mg·kg ⁻¹ ·TS. The effects of nanoparticles on the anaerobic digestion properties of SMX-containing chicken manure were assessed by measuring the following indicators: biogas production by anaerobic digestion, chemical parameters, enzyme concentrations, and bacterial diversity and changes in antibiotic concentrations over time. The law of bacterial degradation of SMX was analyzed. The results showed that (1) adding either nano-Fe ₂ O ₃ or nano-C ₆₀ promoted biogas production by anaerobic production from chicken manure containing different concentrations of SMX, and the cumulative biogas production in Fe ₂ O ₃ and nano-C ₆₀ increased by 35.4% and 130.7%, respectively. The final cumulative biogas productions in different groups were as follows: 3,712(CK), 4,281(S1), 3,968(S2), 4,061(S3), 4,498(S4), and 4,639(S5) mL and the final concentration of SMX residues varied between 99.79% and 99.94%; (2) Bacterial abundance at the phylum level: on day 1, Firmicutes and Bacteroidota were the main dominant bacterial phyla, with relative abundances of 45.13–68.53% and 26.12–48.32%, respectively. The addition of nanoparticles increased the abundance of Bacteroidota in S4 and S5 significantly. The abundance of Bacteroidota was slightly higher in the group added with nanoparticles than in S2. On day 50, Firmicutes became the dominant bacterial phylum, and its relative abundance varied little across the groups, ranging from 90.87% to 94.54%; (3) At different stages, the bacterial community structure at the genus level was dramatically affected by substrates. As nutrients were being depleted, some bacterial communities lost their original competitive advantages. On day 5, the relative abundance of Prevotella increased. Especially, the relative abundances of Prevotella in S4 and S5 added with nanoparticles were lower than that in S2 by 8–10%. On day 15, the relative abundance of Prevotella in S2 decreased compared with the control group CK. A decrease was also observed in S4 and S5, although to a smaller extent than in S2.

There have been various environmental issues in the treatment and resource utilisation of solid waste of livestock and poultry industry in Gansu Province. Thus, in this study, manure of cattle, pig, and chicken from farms near the Lanzhou University of Technology in Lanzhou City, Gansu Province were selected as raw materials for composting using 10 % corn stalk as a leavening agent for aerobic static composting. This study focused on bacterial, fungal, and actinomycetes community succession during livestock manure composting and the underlying microbial degradation mechanism. The results demonstrated that during livestock manure composting, the number of the above-mentioned types of microbes was all positively correlated with the temperature of the compost piles. In the initial stage of composting, the number of microbes increased as the temperature increased, and reached the peaks at the highest temperature, after which, their numbers decreased with the decrease in temperature. At the end of composting, in the cattle, pig, and chicken manure compost piles, the number of bacteria were respectively (3.1 ±1.0) · 10 ⁹ CFU·g ⁻¹ d.w., (4.4 ±1.0) · 10 ⁹ CFU·g ⁻¹ d.w. and (6.7 ±1.8) · 10 ⁹ CFU·g ⁻¹ d.w., respectively, those of fungi were (8.6 ±1.2) · 10 ⁴ CFU·g ⁻¹ d.w., (7.2 ±1.6) · 10 ⁴ CFU·g ⁻¹ d.w. and (8.0 ±2.8) · 10 ⁴ CFU·g ⁻¹ d.w., respectively, while those of actinomycetes were (8.8 ±2.2) · 106 CFU·g ⁻¹ d.w., (9.5 ±2.1) · 106 CFU·g ⁻¹ d.w. and (6.32 ±0.98) · 106 CFU·g ⁻¹ d.w., respectively.