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What are the factors that cause ammonia nitrogen to exceed the standard? (two)

Time : 2020-04-15

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What are the factors that cause ammonia nitrogen to exceed the standard? (two)

Earlier, Makinggreen Environmental Protection introduced some reasons why ammonia nitrogen exceeded the standard. Next, Makinggreen Environmental Protection will continue to introduce you to the reasons for the excessive ammonia nitrogen, and continue to understand with Mianjin Environmental Protection.

04. The ammonia nitrogen exceeds the standard caused by too low DO
High-hardness wastewater is particularly prone to fouling. When aeration is started, a microporous detonator is used, and the aeration head will be blocked for a period of time, which causes the DO to be unable to be lifted and the ammonia nitrogen increases.
The function of aeration is oxygenation and agitation, both of which are affected by the clogging of the aeration head, and the nitrification reaction is aerobic metabolism. It is necessary to ensure that the dissolved oxygen in the aeration tank can be carried out normally in a suitable environment, while the DO is too low It will cause nitrification to be blocked and the ammonia nitrogen will exceed the standard.
(1) Replace the aeration head, this method can be considered if the blockage caused by low hardness operation problems;
(2) Transform into a large-pore aerator (for companies with too low oxygen utilization rate, large fan margin and not bad money) or jet aerator (only use the water from the monitoring pool to act as the power fluid, especially the hardness High sewage, remember).

05. The ammonia nitrogen caused by mud age exceeds the standard
There are two situations:
(1) Excessive mud pressure causes ammonia nitrogen to rise.
(2) The sludge backflow is unbalanced, and the difference in sludge backflow between the two systems is too large, resulting in increased ammonia nitrogen on the side with less sludge backflow.
Too much mud pressure and too little sludge backflow will cause the sludge age to decrease, because the bacteria have a generation period, and the SRT is lower than the generation period, which will cause the bacteria to not accumulate in the system and do not form a dominant strain, so the corresponding Metabolites cannot be removed. The average mud age is 3-4 times that of the bacterial generation.

(1) Reduce water ingress or smoldering;
(2) Add sludge of the same type (generally 1, 2 is better for use);
(3) If the problem is caused by the unbalanced sludge backflow, reduce the water inflow or smoldering of the problem series and return part of the sludge to the problem series under the condition of ensuring normal series operation.

06. Ammonia nitrogen caused by ammonia nitrogen impact exceeds the standard
This situation is generally encountered only by industrial sewage or systems where industrial sewage enters the domestic sewage pipeline network. The previous situation was that the temperature of the upstream stripping tower was controlled to decrease, resulting in a sudden increase in ammonia nitrogen in the incoming water, collapse of the denitrification system, and effluent The ammonia nitrogen exceeds the standard, and the ammonia smell in the sewage treatment site is particularly strong (some free ammonia will escape from the aeration).
There is no clear explanation for the impact of ammonia nitrogen. The analysis is caused by the high free ammonia (FA) in the water. Although the effect of FA (free ammonia) on AOB (ammonia oxidizing bacteria / nitrous acid bacteria) is relatively weak, when the FA (free ammonia) ) When the concentration is 10 ~ 150mg / L, it begins to inhibit AOB (ammonia oxidizing bacteria / nitrite bacteria), while free ammonia (FA) is more sensitive to NOB (nitrite oxidizing bacteria / nitrate bacteria). Free ammonia (FA) The inhibitory effect of NOB (nitrite oxidizing bacteria / nitric acid bacteria) at 0.1 ~ 60mg / L. It is well known that the nitrification reaction is performed by nitrite bacteria and nitrate bacteria together to inhibit nitrite bacteria It can directly lead to the collapse of the nitrification system.
Under the condition of ensuring pH, the following three methods perform better and faster at the same time:
(1) Reduce the concentration of ammonia nitrogen in the system;
(2) Add sludge of the same type;
(3) Sultry.

07. The ammonia nitrogen exceeds the standard caused by the low temperature
This situation mostly occurs in sewage treatment plants without heat preservation or heating in the north, because the water temperature is lower than the appropriate temperature of nitrifying bacteria, and the MLSS is not increased for the slow metabolism in winter, resulting in a decrease in the removal rate of ammonia nitrogen.
Bacteria have lower temperature requirements than humans, but they also have a bottom line, especially for autotrophic nitrifying bacteria. Industrial wastewater is relatively rare, because the temperature of wastewater produced by industrial production does not fluctuate greatly due to changes in ambient temperature. However, the temperature of domestic sewage is basically controlled by the ambient temperature. In winter, the inlet water temperature is very low, especially the temperature difference between day and night is often lower than the temperature required by bacterial metabolism, which makes the bacteria dormant and the nitrification system is abnormal.
(1) In the design stage, make the pool body buried (small-scale sewage treatment is more suitable);
(2) Increase the sludge concentration in advance;
(3) Inlet water heating, if there is a homogeneous adjustment tank, it can be heated in the tank, so the fluctuation is relatively small, if it is direct inlet water, electric heating or steam heat exchange or mixing can be used to increase the water temperature, which requires more precise temperature control To control the fluctuation of inlet water temperature;
(4) Aeration heating is relatively niche. It has not been encountered so far. In fact, the temperature has been raised during air compression blast. If the aeration tube can bear it, you can consider heating the compressed air to increase the temperature of the biochemical pool.

08. Process selection problem
The processes selected for nitrogen removal are simply aeration tank, contact oxidation, SBR, etc. In fact, these processes can remove ammonia nitrogen under the condition that HRT (hydraulic residence time) and SRT (mud age) are long enough. However, in practice, it is not economical and cannot be achieved!
(1) Extend HRT and SRT, for example, transform into MBR to increase mud age, etc .;
(2) Add a denitrification tank in front.
About the reason why ammonia nitrogen exceeds the standard, Mianjin Environmental Protection will introduce you to here first, and continue to pay attention to Mianjin Environmental Protection ~
Makinggreen Environmental Protection Technology (Shanghai) Co., Ltd. is committed to bringing internationally advanced water, gas, solid waste treatment technology and operation management concepts to professional customers in the Chinese market, providing customers with mature, stable, cost-effective overall solutions. We have an expert team composed of domestic and foreign water treatment environmental engineers and well-known professors. We have several independent invention patents and biological treatment core technology process packages to provide nanny lists for customers' sewage treatment systems, exhaust gas systems and sludge solid waste treatment projects. service.
Companies adhering to the "take from nature, anti-replenishment of nature" concept, has a variety of microbial strains and biological nutrition products can be widely used in wastewater, waste gas, river treatment and other environmental protection fields. The company has participated in leading nearly 100 large-scale environmental protection projects at home and abroad. Typical domestic customers include Sinopec, PetroChina, Shenhua Group, Baosteel Group, Roche Pharmaceutical, Formosa Plastics Group, etc. At the same time, the company and the Chinese Academy of Sciences, Tongji University, Central South University, Zhejiang University of Technology and other scientific research institutions and well-known universities jointly research and develop, and strive to become a comprehensive professional environmental protection company integrating production and sales, project EPC general contracting, ecological environment consulting services, and contract operation.