Carbon and water footprint analysis of pig farm buildings in Northeast China using building-information-modeling enabled assessment.

Environmental impact evaluation of buildings is critical for further analysis and optimization of pig farms for sustainable pork production. This study is the first attempt to quantify the carbon and water footprints of a standard intensive pig farm building using building information modeling (BIM) and operation simulation model. The model was constructed with carbon emission and water consumption coefficients, and a database was built. The results showed that the operational stage of pig farm accounted for most of the carbon footprint (49.3-84.9 %) and water footprint (65.5-92.5 %). Building materials production ranked second in carbon (12.0-42.5 %) and water footprints (4.4-24.9 %), and pig farm maintenance ranked third in carbon (1.7-5.7 %) and water footprints (0.7-3.6 %). Notably, the mining and production stages of building materials contributed the largest carbon and water footprints of pig farm construction. Masonry materials have a significant impact on the overall carbon and water footprints of the pig farm. Pig farm using aerated concrete could reduce 41.1 % of the total carbon footprint and 58.9 % of the total water footprint compared to that using coal gangue sintered brick and autoclaved fly ash brick. This study presented a BIM-enabled method for carbon and water footprint analysis of pig farms and illustrated how the model can be used to facilitate the low carbon design of agricultural buildings.

Enhanced efficiency of enzymatic hydrolysis of wheat straw via freeze-thaw pretreatment.

This research investigated enhancing the efficiency of enzymatic hydrolysis of wheat straw via freeze-thaw pretreatment and assessed the physicochemical structural changes after this pretreatment. The enzymatic hydrolysis efficiency of cellulose and hemicellulose was enhanced, and hemicellulose was more susceptible to pretreatment. The highest enzymatic hydrolysis efficiency of cellulose and hemicellulose was 57.06 and 70.66%, respectively, at - 80 ℃ for 24 h and - 10 ℃ for 24 h, respectively, which were 2.23 and 3.13-fold higher than the control levels, respectively. Scanning electron microscopy images indicated that transverse cracks appeared before longitudinal cracks with stronger pretreatment conditions, and holes were found in every sample after this pretreatment. Fourier transform infrared spectroscopy and X-ray diffraction analysis indicated that freeze-thaw pretreatment affected both the crystalline and amorphous regions and disrupted the hydrogen bonds within them. This study provides a physical pretreatment method to improve the efficiency of enzymatic hydrolysis of wheat straw.

Effects of Partial Organic Substitution for Chemical Fertilizer on Antibiotic Residues in Peri-Urban Agricultural Soil in China.

Recycling of organic wastes in agricultural ecosystems to partially substitute chemical fertilizer is recommended to improve soil productivity and alleviate environmental degradation. However, livestock manure- and sewage sludge-derived amendments are widely known to potentially carry antibiotic residues. The aim of this study is to investigate how substituting organic fertilizer for chemical fertilizer affects soil quality and antibiotic residues in agricultural soil, as well as their tradeoffs. A field experiment was conducted with the different treatments of pig manure and sewage sludge as typical organic fertilizers at equal total nitrogen application rates. The analysis of variance showed that the increments on the levels of residual antibiotics in the agricultural soils due to organic substitution for chemical fertilizer by pig manure and sewage sludge were observed. The antibiotic residues ranged from 13.73 to 76.83 ng/g for all treatments. Partial organic substitution significantly increased the sequestration of antibiotics in agricultural soil by 138.1~332.5%. Organic substitution will also significantly improve soil quality, especially for nutrient availability. Based on principal component analysis, organic substitution will strongly affected soil quality and antibiotic contamination. Pearson's correlation showed that soil physicochemical properties had significant correlations with concentrations of antibiotics in soil, indicating organic fertilizers can promote the persistence of antibiotics in soil by modifying soil quality. To balance the benefits and risks, appropriate management practices of organic fertilizers should be adopted.