| Compared with traditional process for removal of ammonium, ANAMMOX (anaerobic ammonium oxidation) process has many advantages. So many scholars attached much importance to this process from domestic to abroad. But ANAMMOX biomass is a new style autotrophic bacteria, which grows slowly and is sensitive to conditions, so it is difficult to cultivate this kind of bacteria. In addition, study on organic wastewater containing high concentration ammonium and high concentration sulphate arouses attention of many scholars. The found of new process for simultaneous removal of nitrogen and sulphur under anaerobic conditions(ANSRNS) plays an important role in the development of biological treatment wastewater. In experiments, we operate two kinds of reactors which are ASBR (Anaerobic Sequencing Batch Reactor) and ARBC(Anaerobic Rotating Biological Contactor Process) to study the ANAMMOX. The two systems are carried out under anaerobic conditions and inoculated different sludge, with different electron acceptor. At the same time, static experiments are carried out, in order to investigate the influence of many kinds of factors on the cultivation of ANAMMOX bacteria and on the operation results of the system. The results of experiments are as following.1. In order to cultivate the special ANAMMOX bacteria, which uses sulphate as electron acceptor, two experiments are carried out respectively in different substrate proportion: one situation is high concentration sulphate with low COD and ammonium concentration; the other is low concentration sulphate with high COD and ammonium concentration. The experiment shows that the latter situation is more suitable for the process of ANAMMOX.2. During the course of ANSRNS, overly reduction of sulphate can inhibit the course of removal of ammonium. Nitrate can decrease reduction of sulphate, but thephenomenon of ANSRNS don't appear again. It is thought that the course of sulphate reduction inhibit the process of ANSRNS, and the inhibition is irreversible and non-rivalrous. Nitrate is inhibitor of the process of sulphate reduction , and have evident inhibition. The result of experiment shows that the inhibition of nitrate to the course of sulphate reduction is reversible and emulous, which was deeply verified by the dynamic parameters.3. The start-up of ANAMMOX is carried out in single anaerobic sludge and mixed sludge inoculated with aerobic sludge. At the same time, we carried out static experiments. The experiment showed that the process of ANAMMOX is easily developed in the mixed situation. The results of static experiments are consistent with the dynamic experiment. It is thought that there are possible two reasons: one is that aerobic ammonium oxidizing bacteria have anaerobic characteristic; the other is that aerobic sludge of the mixed situation easily forms biological membrane. There is filamentous bacterium in the membrane which may absorb the ANAMMOX bacteria and promote the growth of it.4. After the ANAMMOX phenomenon occurred in the ARBG, the system was still conducted under the following conditions: without light, temperature is 35 + l°C, pH is kept in 8.0 or so. The removal of Ammonium was studied in different HRT, which is respectively 2d, Id, l/2d. The experiment results showed that the removal rate of ammonium is near, respectively 20% and 22%, when the HRT is respectively 2d and Id. However the removal rate decreased to 15% when HRT is changed to l/2d. So it is suitable for the process of ANAMMOX when HRT is between 2d and Id.
|
PDF Full Text Request