Types of carbon sources commonly used in wastewater treatment
Types of carbon sources commonly used in wastewater treatment
1.Methanol
Methanol liquid is a relatively high-quality carbon source for denitrification. It is easy to use by denitrifying bacteria and has a high denitrification rate. However, methanol is a dangerous chemical and its transportation and storage are troublesome. Therefore, the use of methanol is limited in this aspect. For the market where denitrification is used as a carbon source, there is nothing that can be faked about methanol, which can be verified by directly detecting COD.
2.Sodium acetate
Due to its short molecular chain, sodium acetate, as a denitrification carbon source, has a reaction rate second only to methanol, and there is no major risk in transportation and storage. The sodium acetate generally used in the market is sodium acetate trihydrate with a content of 60%. It is divided into liquid and solid. The COD equivalent of liquid is generally 20/250,000, and the equivalent of solid is generally about 460,000. Some businesses will use by-product sodium acetate produced in other industries. The content is generally not too high, but the COD equivalent of liquid by-product sodium acetate is sufficient. Some by-product sodium acetate contains some insoluble substances. There are some polymer substances, which can generally be used in practical applications as long as there are no insoluble substances.
3. Glucose
Since the molecular chain of glucose is longer than that of sodium acetate, it is mostly used to cultivate activated sludge in the preliminary debugging of sewage plants. Of course, it is also used for denitrification and denitrification. The COD equivalent is relatively high, but the BOD value is relatively low. In this way, the COD of industrial glucose will be greatly reduced. So after buying the glucose, you can taste it for saltiness. If it tastes salty, it means a lot of salt has been added. Then test whether the COD equivalent is satisfied!
4.Composite carbon source
Composite carbon source refers to the carbon source produced by compounding other carbon sources, such as methanol, ethanol, sodium acetate and other carbon source materials. However, generally composite carbon sources do not use the above substances, but use scraps from some waste chemical products. These scraps come in all shapes and sizes, including waste ethanol, methanol, formaldehyde, acetic acid, sodium acetate, and even macromolecular organic matter. Although the COD value in these composite carbon sources can be reached, there is no guarantee that there are no harmful substances (heavy metals, toxic organic matter, toxic inorganic matter, etc.) in these composite carbon sources. As a denitrification carbon source, it is likely to reduce sludge activity and detoxify. Nitrogen efficiency is reduced, and in severe cases, it may lead to the collapse of the biochemical system, so we must be cautious in this situation.
5. Biological carbon source
Biological carbon source refers to the extremely cost-effective treatment of some macromolecular sugars, agricultural waste, etc. through bioengineering principles. However, the biomass carbon sources sold on the market are sometimes not completely fermented. Although the COD can meet the requirements, there are still long-chain organic matter in them, which are not easily utilized by denitrifying bacteria, and may also cause the effluent COD to exceed the standard.
In practical applications, the most famous one is the application of Tsingtao Brewery wastewater as a carbon source for sewage treatment. Turning beer wastewater into treasure and using it as a carbon source for sewage treatment plants not only solves the high cost of beer wastewater treatment, but also solves the shortage of carbon sources for denitrification and denitrification in sewage treatment plants.
