畜禽粪便堆肥过程中雌激素降解特征.

The aim of this work was to investigate the characteristics of estrogen degradation in livestock manures during composting. Natu⁃ ral estrogens containing estriol（E3）and 17β-estradiol（17β-E2）, were detected in chicken, pig, and cow manures from farms in Nanjing. The synthetic estrogen, containing ethinyloestradiol（EE2）and bisphenol A（BPA）, were also detected. Experimental composting of three livestock manures was conducted, and the concentrations of four estrogens were detected at 0, 2, 4, 8, 16 days, and 32 days. Cow manure, as a representative of all manures, was composted under different turning frequencies（i.e., never turned, turned once every two days, and turned twice every day）to study the impact of turning frequency on estrogen degradation. The results showed a high concentration of native estrogens detected in all three livestock manures. Chicken and cow manures contained synthetic estrogen. The EEQ values of estrogen in chicken, pig, and cow manures were 3 595.86, 268.84 μg·kg-1, and 1 207.12 μg·kg-1, respectively. A high contamination risk existed in all three livestock manures. The residual rates of EEQ in chicken, pig, and cow manures were 10.1%, 10.6%, and 0 after 32 d of composting, which showed that composting could significantly reduce the risk of estrogen contamination. The initial concentration of estrogen had a significant impact on their degradation when various estrogens were detected in livestock manures. The estrogen with the highest concentration degraded faster than other estrogens. Furthermore, estrogen degradation changed with microbial activity in the manure piles. Microbial activity was most active during the mid-stage of composting, and the degradation rate of estrogens was higher during this period than during the early and later stages. Turning the cow manure pile increased its oxygen content, which significantly accelerated estrogen degradation. Thus, turning the manure pile during composting was effective. However, there was little difference in rate of estrogen degradation between turning once every two days and turning twice per day, and the increase in turning frequency did not significantly influence manure composting. [ABSTRACT FROM AUTHOR]