New technology of biological denitrification of sewage-short-cut nitrification-denitrification process (2)

(3) Sharon-Anammox combined process The combination of Sharon process as nitrification reaction and Anammox process as denitrification reaction can overcome the disadvantages of Sharon process denitrification which requires consumption of organic carbon source and relatively high effluent concentration
.

It is to control the Sharon process for partial nitrification, so that the ratio of NH ₄ ⁺ to NO ₂ ^- in the effluent is 1:1, which can be used as the feed water of the Anammox process to form a new biological denitrification process, as shown in Figure 6-2 Show

The Sharon-Anammox combined process has obvious advantages compared with traditional nitrification/denitrification:

①Reduce oxygen demand by 50%～60%;

②No additional carbon source is required;

③The sludge output is very low;

④High nitrogen conversion rate [6kg/(m ³ ·d)] (The ammonia nitrogen removal rate of Anammox process reaches 98.

2%)

Figure 6-2 Sharon-Anammox combined process schematic (anaerobic ammonia oxidation A ² /O test process)

(4) OLAND process OLAND (Oxygen-Limited Autotrophic Nitrification and Denitrifi-cation) process, also known as oxygen-limited autotrophic nitrification and denitrifi-cation process
.

The OLAND process is a new type of biological denitrification process that combines oxygen-limited nitrosation and anaerobic ammonia oxidation.
It was developed by the Microbial Ecology Laboratory of Ghent University in Belgium in 1996

The biological denitrification system realizes the stable operation of biological denitrification at a lower temperature (22～30℃), and realizes the stable accumulation of nitrite in the nitrification stage through oxygen-limiting regulation.

At the same time, it is proposed that the process of anaerobic ammonia oxidation A new concept of microbial action mechanism

In the OLAND system, the key to controlling the reaction is the supply of oxygen, that is, how to provide suitable oxygen so that the nitration reaction only proceeds to the nitrous acid stage
.

At present, this control can only be achieved in pure bacterial culture, but it is difficult to achieve in continuous mixed bacterial culture

(5) Completely Auto-trophic Nitrogen Removal Over Nitrite (CANON) in the biofilm system (CANON) is that nitrosation can occur inside the biofilm system.
If the system is insufficiently supplied with oxygen Then Anammox inside the membrane can also occur at the same time, so the integrated complete autotrophic nitrogen removal process in the biofilm may be realized
.

In practice, this integrated autotrophic denitrification phenomenon has indeed been observed in some projects or experiments, and its working principle is shown in Figure 6-3

In a biofilm system that supports simultaneous nitrification and Anammox, there are usually three different autotrophic microorganisms: nitrosating bacteria, nitrifying bacteria and anammox bacteria
.

These three bacteria compete for oxygen, ammonia nitrogen and nitrite nitrogen

 

Figure 6-3 Process principle of autotrophic nitrogen removal in biofilm

Related Links: New Technology of Biological Nitrogen Removal from Wastewater-Short-cut Nitrification-Denitrification Process (1)