Nitrogen Removal Of OLAND-SMBR Process By Using Biogas Mixed With Air Aeration

Anammox bacteria are autotrophic bacteria, there is no need to add additional organic carbon. Meanwhile anaerobic ammonia oxidation technology has short reaction pathways and high efficiency. Compared with conventional denitrification technology, it is more economical and more convenient. But anammox bacteria’s slow growth, long multiplication cycle, and severe growth conditions, making it difficult to concentrate in a conventional reactor, which makes it difficult to apply to industrial production. Aiming at the exising problems of Anammox, a submerged membrane bioreactor (SMBR) was developed in this study.A new biological nitrogen removal thchnology-OLAND process was setted up. The mixed gas was to offer oxygen for AOB and purge membrane for fouling alleviatation The main results are as follows:(1) The ammonia-oxidizing bacteria was successfully cultivated in the continuous stirred-tank reactor by controlling the reactor dissolved oxygen (DO) and free ammonia (FA) concentration. The reaction operated at room temperature (20 ± 3 ℃) for 37 days and the ammonia conversion rate was 54%. The growth of nitrite-oxidizing bacteria is inhibited by low dissolves oxygen.(2) Anammox bacteria were enriched in submerged membrane bioreactor (SMBR). The reactor was successfully operated for 70 days.The maximum nitrogen loading rate was 0.5 kg TN/m3-d and total nitrogen removal rate remained at 85%.(3) The OLAND process was successfully setted up in the submerged membrane bioreactor (SMBR). Using mixed gas sparging method aims to offer oxygen for the bacteria and alleviates the membrane fouling. The nitrogen loading rate was 0.5 kg TN/m3·d and total nitrogen removal rate was over 84%.(4) Different aeration was investigated to study the membrane fouling. The results showed that:increase the aeration rate can effectively extend membrane life cycle, but if the aeration rate is too high, the treatment effect will fall down. In sudy, the optimum aeration rate was 0.1 m3/h (air aeration of 0.05 m3/h+circulation aeration of 0.05 m3/h). Although aeration could not avoid membrane fouling, with the increase in aeration rate, membrane fouling could be effectively alleviated.