Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Canada.
Environ Technol. 2021 Mar;42(7):984-1000. doi: 10.1080/09593330.2019.1650122. Epub 2019 Aug 4.
Anoxic co-biodegradation of linear and cyclic naphthenic acids (NAs) namely octanoic acid, trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), cis- and trans-4-methyl-1-cyclohexane-acetic acids (cis-4MCHAA and trans-4MCHAA) was investigated in denitrifying biofilm reactors. In all evaluated compositions, co-biodegradation of NAs was coupled to denitrification, with octanoic acid showing the fastest biodegradation rate (1180.4 mg L h at loading rate of 1180.4 mg L h), followed by trans-4MCHCA (398.1 mg L h at loading rate of 435.8 mg L h), trans-4MCHAA (25.7 mg L h at loading rate of 221.7 mg L h), and cis-4MCHAA (5.3 mg L h at loading rate of 16.9 mg L h). Biodegradation of octanoic acid and trans-4MCHCA were not influenced by the presence of recalcitrant NAs (cis- and trans-4MCHAA). Co-biodegradation of cis- and trans-4MCHAA with octanoic acid, trans-4MCHCA, or their combination enhanced the biodegradability of these recalcitrant NAs, with the positive impact being more pronounced for trans-4MCHCA. Finally anoxic co-biodegradation of NAs under denitrifying conditions proceeded at rates that were faster than the aerobic rates obtained in similar mixtures. Anoxic biodegradation, therefore, is an effective alternative for in situ treatment of oil sands process water in anoxic stabilization ponds amended with nitrate, or as an ex situ treatment approach in denitrifying bioreactors whereby the cost and technical challenges of aeration are eliminated.
在反硝化生物膜反应器中研究了直链和环状环烷酸（NA）即辛酸、反式-4-甲基-1-环己烷羧酸（反式-4MCHCA）、顺式和反式-4-甲基-1-环己烷乙酸（顺式-4MCHAA 和反式-4MCHAA）的缺氧共生物降解。在所评估的所有组成中，NA 的共生物降解与反硝化耦合，辛酸表现出最快的生物降解速率（在 1180.4 mg L h 的负荷速率下为 1180.4 mg L h），其次是反式-4MCHCA（在 435.8 mg L h 的负荷速率下为 398.1 mg L h），反式-4MCHAA（在 221.7 mg L h 的负荷速率下为 25.7 mg L h），顺式-4MCHAA（在 16.9 mg L h 的负荷速率下为 5.3 mg L h）。难生物降解的 NA（顺式和反式-4MCHAA）的存在并不影响辛酸和反式-4MCHCA 的生物降解。辛酸、反式-4MCHCA 或它们的组合与顺式和反式-4MCHAA 的共生物降解增强了这些难生物降解的 NA 的生物降解性，反式-4MCHCA 的影响更为明显。最后，在反硝化条件下进行的 NA 缺氧共生物降解速率比在类似混合物中获得的好氧速率更快。因此，缺氧生物降解是在添加硝酸盐的缺氧稳定塘中原位处理油砂工艺水的有效替代方法，或者是在反硝化生物反应器中进行的异位处理方法，从而消除了曝气的成本和技术挑战。
