engleski

Nitrate removal in the continuous-flow stirred reactor

The presence of excess nitrate in natural water resources is determined and therefore the EU water legislation set a Nitrates directive to reduce and prevent water pollution. As a result, the new methods for nitrate removal are studied and the use of attached bacterial cells was investigated for effective nitrate removal. The main objective of the present study was the use of acclimated bacterial cells that were interacted with natural powdered clinoptilolite and the resulting biozeolite particles (B-NPC) were applied in the continuous-flow stirred reactor for establishing stable and efficient nitrate removal from the surface water (SW). The nitrate removal was monitored in the first set of experiments at different dilution rates (0.027, 0.043, 0.095, 0.429, and 0.755 1/h) in order to achieve the optimal dilution rate. In the first test set, nitrate ions were found in the effluent only at dilution rates of 0.429 and 0.755 1/h. The removal of 100 mg NO3–-N/L from the SW with B-NPC (9% w/w) was monitored during 21 days and complete and efficient removal was achieved at pH of 7-8 and 20-25 °C. Finally, the use of B-NPC in the continuous-flow stirred reactor was demonstrated as an efficient method for nitrate removal from the surface water.

clinoptilolite; continuous-flow stirred reactor; denitrification; mixed bacterial culture; nitrite accumulation

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