CASE2

Lime powder has important applications in wastewater treatment, mainly reflected in the following aspects:

1、 Adjust pH value

The acidity and alkalinity in sewage have a significant impact on the subsequent treatment process and ecological environment. The main component of quicklime powder is calcium oxide (CaO), which reacts with water to produce calcium hydroxide (Ca (OH) ₂), releasing a large amount of hydroxide ions (OH ⁻), thereby increasing the pH value of wastewater. For acidic wastewater, adding an appropriate amount of quicklime powder can adjust the pH value to a suitable range, generally 6-9, to meet the requirements of subsequent biological treatment or chemical precipitation processes. For example, in some industrial wastewater treatment, due to the presence of a large amount of acidic substances such as sulfuric acid, hydrochloric acid, etc., the wastewater exhibits strong acidity. By adding quicklime powder, acidic substances can be quickly and effectively neutralized, restoring the pH value of wastewater to the normal range.

2、 Removing heavy metal ions

Calcium hydroxide can react with many heavy metal ions in water to form insoluble hydroxide precipitates. For example, it can react with heavy metal ions such as copper ions (Cu ² ⁺), lead ions (Pb ² ⁺), and cadmium ions (Cd ² ⁺) to generate corresponding hydroxide precipitates, thereby removing heavy metal ions from wastewater. This method is very effective for treating industrial wastewater containing heavy metal ions. For example, in wastewater treatment in industries such as electroplating, metallurgy, and chemical engineering, quicklime powder is often used to remove heavy metal ions from wastewater. By adjusting the dosage and reaction conditions of quicklime powder, a high removal rate of heavy metals can be achieved, reducing environmental pollution.

3、 Sterilization and disinfection

Lime powder has a certain bactericidal and disinfectant effect. Adding an appropriate amount of quicklime powder in the sewage treatment process can kill bacteria, viruses, parasites and other microorganisms in the sewage, preventing the spread of diseases. This is because calcium hydroxide has strong alkalinity, which can damage the cell membrane and protein structure of microorganisms, leading to microbial death. For example, in the treatment of some domestic sewage and medical wastewater, quicklime powder can be used for preliminary disinfection treatment to reduce the microbial load in the subsequent treatment process.

4、 Improve the properties of sludge

During the sewage treatment process, a large amount of sludge is generated. Lime powder can react with the moisture in sludge, releasing heat and causing the moisture in the sludge to evaporate, thereby reducing the moisture content of the sludge. Meanwhile, quicklime powder can also react with organic matter in sludge, promoting the stabilization and dewatering performance of sludge. For example, adding an appropriate amount of quicklime powder during sludge treatment can reduce the volume of sludge, making it easier to transport and dispose of. In addition, quicklime powder can also enhance the fertility of sludge, making it suitable for use as fertilizer or soil amendment.

In short, quicklime powder has multiple functions in sewage treatment, which can effectively improve the water quality of sewage and reduce environmental pollution. In practical applications, it is necessary to choose the appropriate amount and method of adding quicklime powder based on the properties and treatment requirements of the wastewater, in order to achieve the best treatment effect.