%A Lifeng Cao, Weihua Sun, Yuting Zhang, Shimin Feng, Jinyun Dong, Yongming Zhang, Bruce E. Rittmann %T Competition for electrons between reductive dechlorination and denitrification %0 Journal Article %D 2017 %J Front. Environ. Sci. Eng. %J Frontiers of Environmental Science & Engineering %@ 2095-2201 %R 10.1007/s11783-017-0959-x %P 14- %V 11 %N 6 %U {https://journal.hep.com.cn/fese/EN/10.1007/s11783-017-0959-x %8 2017-12-25 %X

Simultaneous reductive dechlorination and denitrification occurred simultaneously in VBBR.

The mechanism of the mutual inhibition between TCP and nitrate or nitrite was identified clearly.

Declorination was more sensitive to competitive inhibition than either denitrification.

Nitrite had a smaller inhibitory impact on TCP reduction than nitrate.

Both reactions proceed more rapidly if the oxidized nitrogen is nitrite instead of nitrate.

All reactions could be accelerated by exogenous electron donors, and especially for TCP reduction.

It is common that 2,4,6-trichlorophenol (TCP) coexists with nitrate or nitrite in industrial wastewaters. In this work, simultaneous reductive dechlorination of TCP and denitrification of nitrate or nitrite competed for electron donor, which led to their mutual inhibition. All inhibitions could be relieved to a certain degree by augmenting an organic electron donor, but the impact of the added electron donor was strongest for TCP. For simultaneous reduction of TCP together with nitrate, TCP’s removal rate value increased 75% and 150%, respectively, when added glucose was increased from 0.4 mmol·L–1 to 0.5 mmol·L–1 and to 0.76 mmol·L–1. For comparison, the removal rate for nitrate increased by only 25% and 114% for the same added glucose. The relationship between their initial biodegradation rates versus their initial concentrations could be represented well with the Monod model, which quantified their half-maximum-rate concentration (KS value), and KS values for TCP, nitrate, and nitrite were larger with simultaneous reduction than independent reduction. The increases in KS are further evidence that competition for the electron donor led to mutual inhibition. For bioremediation of wastewater containing TCP and oxidized nitrogen, both reduction reactions should proceed more rapidly if the oxidized nitrogen is nitrite instead of nitrate and if readily biodegradable electron acceptor is augmented.