Application of activated carbon filter for sewage treatment

The activated carbon filter is generally used in conjunction with the quartz sand filter. There is no essential difference between the tank body and the quartz sand filter. The internal water distribution device and the main body piping should meet the requirements of use.

Activated carbon filter has two functions:

(1) Use the active surface of activated carbon to remove free chlorine in water, so as to avoid the chlorination of ion exchange resin, especially cation exchange resin in chemical water treatment system, by free chlorine.

(2) Remove organic matter in water, such as humic acid, etc., to reduce the pollution of strong basic anion exchange resin by organic matter. According to statistics, through the activated carbon filter, 60% to 80% of colloidal substances, about 50% of iron and 50% to 60% of organic substances can be removed from water.

In the actual operation of the activated carbon filter, the turbidity of the water entering the bed, the backwash cycle, and the backwash strength are mainly considered.

(1) Turbidity of water entering the bed:

The high turbidity of the water entering the bed will bring too many impurities to the activated carbon filter layer. These impurities are trapped in the activated carbon filter layer, and block the filter gap and the surface of the activated carbon, hindering its adsorption effect. After long-term operation, the retentate will stay between the activated carbon filter layers, forming a mud film that cannot be washed away, causing the activated carbon to age and fail. Therefore, it is best to control the turbidity of the water entering the activated carbon filter below 5ntu to ensure its normal operation.

(2) Backwash cycle:

The length of the backwash cycle is the main factor related to the quality of the filter. If the backwash cycle is too short, the backwash water will be wasted; if the backwash cycle is too long, the adsorption effect of activated carbon will be affected. Generally speaking, when the turbidity of the water entering the bed is below 5ntu, it should be backwashed once every 4~5 days.

(3) Backwash intensity:

During the backwashing of the activated carbon filter, the expansion rate of the filter layer has a great influence on whether the filter layer is completely washed. If the expansion rate of the filter layer is too small, the activated carbon in the lower layer cannot be suspended, and its surface cannot be washed cleanly. In operation, the general controller expansion rate is 40%~50%. (4) Backwash time:

Generally, when the expansion rate of the filter layer is 40%~50% and the recoil strength is 13~15l/(㎡·s), the backwash time of the activated carbon filter is 8~10min.

Post time: Mar-12-2022