The Study On Treatment Of Organic Rich-Ammonia Wastewater By PN-Anammox Process

The partial nitritation-anammox process(PN-Anammox) is a new type of biological denitrification process, with low energy consumption, less sludge production and higher nitrogen removal rate. Especially in the treatment of rich-ammonia wastewater, the process overcomes the problem of insufficient carbon source which the traditional biological denitrification process is faced with. But in reality, most of the rich-ammonia wastewater contain a certain concentration of organic matter. The level of organic matter can't satisfy the requirement of traditional denitrification microorganism, but it has already had an impact on the PN-Anammox process. In order to extend the application range of the PN-Anammox process, the PN-Anammox reactor which was designed by our research team was used for treating organic rich-ammonia wastewater.Taking alcohol wastewater as an example, the experimental result showed that organic matter had no effect on nitritation. In addition, the rate of nitritation was basically unchanged. A large number of denitrification bacteria grew in the anammox region, which competed with anammox bacteria for nitrite, so that the anaerobic ammonium oxidation reaction was inhibited. Since denitrification rate was lower than the initial anammox rate, the nitrogen remove rate of the reactor was also decreased.In the experiment of the effect of organic matter on the nitritation, it was found that the competition of DO by heterotrophic bacteria and AOB could be alleviated by appropriately increasing the aeration rate. In addition organic matter could be removed at the same time. The aeration rate adapted to influent ammonia and organic matter were obtained in a series of experiments.The influence rule of organic matter to anammox were investigated through a series of batch experiments. It was found that the inhibition concentration(ICTOC) of organic matter was related to the initial anammox activity(NRR) of the reactor. When organic matter concentration exceeded ICTOC, the anammox reaction would be inhibited. Then the NRR would be reduced due to the inhibition. When NRR varies from 0.45 to 1.86 kg·m-3·d-1, NRR and ICTOC are exponential function relationship.The method of treating organic rich-ammonia wastewater with series PN-Anammox process was promoted though the effect of organic matter on nitritation and anammox. On the premise of nitritation rate was not affected, the concentration of organic matter in the effluent of nitritation region could be reduced lower than ICTOC, so as to remove the influence of organic matter on the PN-Anammox process. It will relieve the influence of organic matter on the PN-Anammox process. The above scheme was verified in the following experiments.When influent NH4+-N concentration was 250mg·L-1, aeration rate was 300L·h-1, HRT 10 h, pH 8.0, temperature 30?, the PN-Anammox reactor in which volume ratio of nitrite region and anammox region was approximatively 10 ran stably. In addition its NRR was 0.6 kg·m-3·d-1. After a period of time, get the influent NH4+-N increase to 80 mg·L-1 that was greater than the ICTOC, at the same time raise aeration rate to 500 L·h-1. After a long time operation, the organic matter did not inhibit the reactor. It demonstrates that the above control strategy can make PN-Anammox process be successfully used in the treatment of organic rich-ammonia wastewater.