To solve the problem of poor sludge dewatering effect, the selection of sludge conditioner is indeed the key. The following are some detailed recommendations on the selection of sludge conditioner:
A, according to the nature of sludge selection
Organic content:
For the sludge with high organic matter content, it is recommended to use cationic organic polymer conditioner, and the higher the organic matter content, the more suitable to choose the product with higher polymerization degree.
For inorganic sludge, anionic organic polymer conditioner can be considered.
Sludge dewatering performance:
Activated sludge is often poor in water dewatering, so it is necessary to choose a conditioner that can effectively improve its dewatering performance.
The dewatering performance of the sludge after anaerobic digestion is better, but it may be necessary to choose the appropriate conditioner according to the specific situation to further optimize the dewatering effect.
Two, consider the pH of the sludge
Different conditioners have different effects on sludge treatment at different pH values. For example:
The hydrolysis reaction of aluminum salt is greatly affected by pH value, and the optimal pH value of the condensation reaction is 5~7. When the pH value deviates from this range, the conditioning effect of aluminum salt will be significantly reduced.
Ferric salt conditioner is less affected by pH value. No matter the sludge is acidic or alkaline, it can form Fe(OH)3 floc, the best pH value range is 6~11.
Therefore, when selecting the conditioner, it is necessary to fully consider the pH value of the sludge to ensure that the conditioner can play the best effect.
Three, choose the right conditioner concentration
The concentration of the conditioner not only affects the conditioning effect, but also relates to the consumption of the agent and the yield of the sludge dehydrating agent. In general:
The lower the concentration of the organic polymer conditioner, the less the drug consumption, the better the conditioning effect. But too low or too high concentration will reduce the yield of mud cake. The general recommendation is between 0.05% and 0.1% is more appropriate.
The preparation concentration of inorganic polymer adjuster (such as ferric chloride) needs to be determined according to the specific situation, generally the preparation concentration of ferric chloride is 10%, and the preparation concentration of aluminum salt is 4% to 5%.
Four, consider the temperature of the mixed treatment solution
The sludge temperature directly affects the hydrolysis of the conditioner. When the temperature is low, the hydrolysis will be slow, especially when the temperature is lower than 10℃, the sludge conditioning effect will be significantly reduced. In this case, you can improve the effect by:
Appropriate extension of conditioning time.
Select a drug with strong adaptability to low temperature.
Heat the conditioner dilution tank.
Increase the stirring intensity to improve the dissolution conditions.
Five, through the test to determine the best conditioner type and dosage
In order to determine the most suitable type and dosage of conditioner, a precipitation test is recommended. The test can be carried out by six mixers, and the optimal type and dosage of the conditioner can be determined by measuring the turbidity of the supernatant. This ensures that the selected conditioner will work best in practical applications.
Six, consider the combination with other chemicals
If a conditioner alone does not produce the desired effect, it can be considered in combination with other chemicals. For example, an inorganic conditioner (such as lime, iron salt) can be combined with an organic conditioner (such as PAM, PAA) to improve the dewatering performance of the sludge. However, it is necessary to pay attention to the compatibility and reaction conditions between different chemicals to avoid negative effects.
In summary, to solve the problem of poor sludge dewatering effect, it is necessary to consider the nature of the sludge, pH, conditioner concentration, temperature and other factors such as the combination of other chemicals. Through scientific and reasonable selection and use of conditioner, the dewatering effect of sludge can be significantly improved and the treatment cost can be reduced.