Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
Ecotoxicol Environ Saf. 2020 Jun 15;196:110547. doi: 10.1016/j.ecoenv.2020.110547. Epub 2020 Mar 31.
Large molecular weight pig biogas slurry (L-PBS) and small molecular weight pig biogas slurry (S-PBS) were separated from original pig biogas slurry (O-PBS) using a 100 kDa membrane. The original bioavailability and biosafety of L-PBS was very low. In order to enhance the total bioavailable dissolved organic nitrogen (TB-DON) and total bioavailable dissolved organic phosphorus (TB-DOP), optimum catalytic ozonation of L-PBS conditions were determined using Box-behnken design models (P < 0.0001) and intersection tests. The optimal values for ozone concentration, pH value, active catalyst concentration and reaction time were 2.63 mg·L, 6.48, 1.43 g·L and 40 min, respectively. Catalytic ozonation can effectively decompose and transform 68.07% of L-PBS into S-PBS to improve content organic bioavailability, with a molecular weight distribution of 0-1 kDa (13.53%), 1-5 kDa (16.62%), 5-10 kDa (11.16%), 10-30 kDa (11.73%), 30-100 kDa (15.04%). Catalytic ozonation of L-PBS can reduce protein levels from 85.28% to 47.18%, but increases the proportion of fulvic and humic components from 10.22% to 32.67% and 4.51%-20.15%, respectively. Because catalytic ozonation changes the internal components and molecular weights of L-PBS, both saw increases in TB-DON and TB-DOP from 3.33% to 41.12% and 2.43%-37.88%, respectively, with a large number of TB-DON and TB-DOP derived from hydrophilic organic components during catalytic ozonation. These important internal mechanisms changed by catalytic ozonation can effectively reduce the ecotoxicity (IR, from 76.5% to 33.1%) and phytotoxicity (GI, enhanced from 35.4% to 70.3%) of L-PBS. Therefore, catalytic ozonation combined with membrane separation is a choice technology in improving the nutrition of biogas slurry and reduce its ecological risk.
采用 100 kDa 膜从原始猪沼气发酵液（O-PBS）中分离出大分子量猪沼气发酵液（L-PBS）和小分子量猪沼气发酵液（S-PBS）。L-PBS 的原始生物利用度和生物安全性非常低。为了提高总可生物利用溶解有机氮（TB-DON）和总可生物利用溶解有机磷（TB-DOP），使用 Box-Behnken 设计模型（P < 0.0001）和交点测试确定了 L-PBS 的最佳催化臭氧化条件。臭氧浓度、pH 值、活性催化剂浓度和反应时间的最佳值分别为 2.63 mg·L、6.48、1.43 g·L 和 40 min。催化臭氧化可以有效地将 68.07%的 L-PBS 分解转化为 S-PBS，以提高有机物的生物利用度，分子量分布为 0-1 kDa（13.53%）、1-5 kDa（16.62%）、5-10 kDa（11.16%）、10-30 kDa（11.73%）、30-100 kDa（15.04%）。L-PBS 的催化臭氧化可以将蛋白质水平从 85.28%降低到 47.18%，但会增加富里酸和胡敏酸成分的比例，分别从 10.22%增加到 32.67%和 4.51%-20.15%。由于催化臭氧化改变了 L-PBS 的内部成分和分子量，TB-DON 和 TB-DOP 分别从 3.33%增加到 41.12%和 2.43%-37.88%，催化臭氧化过程中大量的 TB-DON 和 TB-DOP 来源于亲水性有机成分。这些由催化臭氧化引起的重要内部机制的变化可以有效降低 L-PBS 的生态毒性（IR，从 76.5%降低到 33.1%）和植物毒性（GI，从 35.4%提高到 70.3%）。因此，催化臭氧化结合膜分离是提高沼气发酵液营养水平和降低其生态风险的一种选择技术。
