Views: 0 Author: Site Editor Publish Time: 2024-06-06 Origin: Site
Methanol as an external carbon source has the advantages of low operating cost and small sludge production, and there is nitrite accumulation when the methanol carbon source is insufficient. The denitrification rate of methanol as a carbon source is 3 times faster than that of glucose as a carbon source, and its better carbon/nitrogen ratio (COD: ammonia nitrogen) is 2.8-3.2. However, there are the following 3 points to be concerned about when methanol is used as an external carbon source:
1. Methanol is flammable and a Class A hazardous chemical, and there are strict requirements for its storage and use. In particular, its storage needs to be reported to the local public security department for record and approval, which is a cumbersome procedure.
2. The response time of microorganisms to methanol is slow, methanol can not be used by all microorganisms, when methanol is used in wastewater treatment plants for emergency addition of carbon source when the effect is not good.
3. Methanol has a certain toxic effect, the use of methanol as a long-term carbon source, the discharge of tail water will also have a certain impact.
The advantage of sodium acetate is that it responds immediately to the denitrification process and can be used as an emergency disposal in water plants. Sodium acetate is easy to be utilised by denitrifying bacteria due to small molecule organic acid salts, and the effect of nitrogen removal is better. Through the experiment, it was found that the carbon and nitrogen ratio of 4.6 can achieve stable denitrification effect, and its hydrolysate is small molecule organic matter, which can be easily degraded by microorganisms, the denitrification response time is fast and non-toxic, and it can be used as an emergency carbon source. However, it is more expensive and has a high sludge production rate, which puts a certain pressure on the sludge disposal of sewage plants.
There are 3 points to consider when using sodium acetate:
1. Sodium acetate is mostly 20%, 25% and 30% liquid, which cannot be transported over long distances due to low equivalent COD and high transport costs.
2. Sludge production is high and sludge treatment costs increase.
3. The price is more expensive, and it is almost impossible to add sodium acetate to sewage treatment plants on a large scale.