01 Organic matter caused by excessive ammonia nitrogen
For high ammonia nitrogen wastewater with CN ratio less than 3, the nitrogen removal process requires CN ratio between 4 and 6, so carbon source should be added to improve the completeness of denitrification. The carbon source added is methanol. Due to some reasons, the outlet valve of the methanol storage tank falls off, and A large amount of methanol enters pool A, which leads to A lot of foam in the aeration tank, and the effluent COD and ammonia nitrogen soar, and the system crashes.
Analysis: A large number of carbon sources into pool A, denitrification can not be utilized, into the aeration tank, because of sufficient substrate, heterotrophic bacteria aerobic bolism, A large amount of oxygen and trace elements consumption, because nitrifying bacteria are autotrophic bacteria, poor bolism, oxygen is contested, can not form the dominant species, so the nitrification reaction is limited, ammonia nitrogen increased.
Solutions:
(1) Immediately stop the water inlet for suffocating explosion and continuous opening of internal and external reflux;
(2) Stop mud pressing to ensure sludge concentration;
(3) If the organic matter has caused the expansion of non-filamentous bacteria, PAC can be added to increase the flocculation of sludge, and defoaming agent can be added to eliminate the impact foam.
Excess ammonia nitrogen due to internal reflux
There are several reasons for exceeding the standard of ammonia nitrogen caused by internal reflux: the internal reflux pump has electrical failure (site skip throw operation signal), mechanical failure (impeller off) and human reasons (internal reflux pump did not try positive and negative, the site is in reverse state).
Analysis: Excessive ammonia nitrogen caused by internal reflux can also be attributed to the impact of organic matter, because there is no reflux of nitrification liquid, resulting in only A small amount of nitrate nitrogen carried by external reflux in pool A, the overall anaerobic environment, carbon source will only hydrolyze acidification, but not completely bolized into carbon dioxide escape. So a large amount of organic matter into the aeration tank, resulting in the increase of ammonia nitrogen.
Solutions:
The problem of internal reflux is very easy to find, and can be judged by the data and trend whether it is caused by internal reflux: in the early stage, the nitrate nitrogen in pool O increases, the nitrate nitrogen in pool A decreases to 0, and the pH decreases, etc., so the solutions can be divided into three situations:
(1) Timely discovery of problems, maintenance of internal reflux pump can be;
(2) Internal reflux has led to the increase of ammonia nitrogen, repair the internal reflux pump, stop or reduce the water intake for suffocating explosion;
(3) The nitrification system has collapsed and the inlet water is stopped to suffocate. If conditions are available and the situation is relatively urgent, biochemical sludge similar to the denitrification system can be added to speed up the recovery of the system.
Excessive ammonia nitrogen due to low 03pH
There are three cases of excessive ammonia nitrogen caused by too low pH:
(1) the return is too big or the back of aeration open too big, lead to carry large amounts of oxygen into A pool, destroy the hypoxia environment, aerobic denitrifying bacteria, organic matter is aerobic bolism, serious impact on the integrity of the denitrification, because denitrification can compensate nitration bolic off half of alkalinity, so the destruction of the environment leads to lack of oxygen to reduce alkalinity, When pH is lower than the suitable pH of nitrifying bacteria, nitrification reaction is inhibited and ammonia nitrogen increases. This situation may be encountered by some peers, but never from this aspect to find the reason.
(2) The influent CN ratio is insufficient, which is also caused by incomplete denitrification and less alkalinity, resulting in pH decline.
(3) The pH decreases continuously due to the decrease of influent alkalinity.
Analysis: Ammonia nitrogen exceeding the standard caused by pH reduction has a relatively low probability of occurrence in practice, because the continuous decrease of pH is a process, and the general operation personnel will open it when they do not find the problem