A study on the comparison of coated nitrifying bacteria on nitrification efficiency and distribution of nitrifying bacteria

Nitrification characteristics and performance of wastewater treatment plants depend on not only temperature, pH, and dissolved oxygen of the wastewater but also species, distribution, and their metabolic stages of nitrifying bacteria. Due to their low specific growth rate, nitrifying bacteria are easy to wash out of the reactor and need long time to start-up and recover from damaged nitrifiers community. In order to overcome this limitation, nitrifying bacteria were coated on a polyurethane-based media. Laboratory and pilot-scale reactor had been designed and operated to compare the effect of coated nitrifying bacteria on wastewater nitrification efficiency and performance. Furthermore, the species and quantitative distribution of nitrifying bacteria were also investigated in the suspension and on the media. The results showed that nitrifier-coated reactor had better nitrification efficiency and performance than the control experiments. It also demonstrated that the amounts of total nitrifying bacteria of a coated reactor was higher than other reactors and it increased with operation time and wastewater temperature.

생물반응기의 운전 특성과 성능은 온도나 pH, 용존산소 등의 물리화학적 조건 외에 미생물의 종류와 분포비율, 미생물의 대사상태에 따라서도 매우 다양한 특성을 보인다. 질산화 미생물 코팅 담체를 투입한 반응조에서는 담체가 없는 반응조에 비해 질산화 미생물의 양이 증가하였고, 또한 질산화 미생물이 코팅된 담체를 사용한 반응기는 코팅되지 않은 담체를 투입한 반응조에 비해 질산화 미생물 양의 상승효과가 있었다. 질산화 미생물의 양은 운전 기간과 수온의 상승에 따라 증가하는 것으로 나타났다.