Effects of High Temperature on the Nitrification Performance using Moving Bed Bioreactor

Abstract

Biological nitrification-denitrification process is cost-effective and energy-saving way to treat nitrogen wastewater. Many early studies have reported the effects of low temperatures on nitrogen removal performance, but not the effects of high temperatures. In Japan, it has been confirmed that the maximum temperature in summer exceeds 40℃. In the present study, we evaluated the effect of high temperature on nitrification performance in a continuous test system using two different types of carriers such as a polyvinyl alcohol sponge carrier （PVA carrier） and a polyethylene tubular carrier （PE carrier）. Consequently, no significant effect was observed when water temperatures was rapidly increased to 35, 38 and 40℃. However, when the water temperature was raised to 43℃, an increase in the nitrite concentration in the effluent was confirmed. Moreover, the nitrification activity decreased significantly when the water temperature was further raised to 45℃. As a result of the test of gradually raising the water temperature from 35℃ to 45℃ for about 4 months, the effluent nitrogen concentrations were not affected up to 43℃. However, effluent ammonium concentration was rapidly increased when the water temperature was raised to 45℃. Microbial community analysis revealed that the difference of microbial structure among two carriers, and response to the temperature changes.