Start-up of CANON reactor with modified polyethylene carrier and its performance

A CANON reactor with modified polyethylene carrier was started up by seeding sludge from another mature CANON reactor and using artificial inorganic ammonia-rich waste water as influent. To accelerate ANAMMOX bacteria cultivation, the start-up was under anaerobic conditions first to avoid dissolved oxygen inhibition on ANAMMOX bacteria, and then under aerobic conditions. The reactor was first under anaerobic conditions to start ANAMMOX process at room temperature [(20±5)℃] in first 300 days, however, total nitrogen removal load was only 0.12 kg·(m3·d)-1, which meant failure of ANAMMOX. When temperature was increased to 30℃, 30 days later, total nitrogen removal load was up to 0.23 kg·(m3·d)-1. Then anaerobic conditions was changed to aerobic conditions, and total nitrogen removal load was up to 1.01 kg·(m3·d)-1, while nitrogen removal efficiency was 77.61%, and average variation ratio of nitrate and nitrogen (δNO3--N/δTN) was 0.122, close to theoretical value 0.127, showing both good stability of nitritation and good nitrogen removal. Adopting the way of anaerobic stage first and then aerobic stage could not accelerate ANAMMOX bacteria cultivation as expected, and modified polyethylene carrier was not a suitable carrier to start ANAMMOX process under anaerobic conditions. However, once the reactor was successfully started up, aeration could be saved, though it might perform unstably. Modified polyethylene carrier was suggested to combine with UASB reactor to keep bacteria. ©All Rights Reserved.