1. Basic Principles and Functions

For inorganic colloids with particle sizes ranging from 10 to 20 angstroms, dissolved organic macromolecular impurities, and residual chlorine that are difficult to remove during mechanical filtration, in order to further deeply purify the raw water and make it meet the inlet water standards for the RO machine, an activated carbon unit was designed in the process flow. The reason why activated carbon can adsorb active substances with particle sizes of several tens of angstroms is that its structure contains a large number of micropores and intergranular spaces with diameters ranging from 20 to 50 angstroms. This special structural characteristic of activated carbon enables its specific surface area to reach 500-2000 m2/g. Generally, the molecular radius of organic substances is slightly less than 10-25 angstroms, so activated carbon is the most effective in adsorbing organic substances. Additionally, it has a strong dechlorination ability, reducing the chlorine content in the raw water to less than 0.1 ppm. Generally, pressure filters and multi-media filters are similar. They can be made into simple adsorption columns or combined with quartz sand to form adsorption filtration columns. Both can remove organic substances and filter out suspended solids. The filtration speed is generally 10-15 m/h, and the backwashing intensity is generally 4-12 L/(s.m2).

2. Maintenance and Care (1) Daily maintenance of the activated carbon adsorption box: The daily maintenance tasks for the equipment include regularly checking whether the fans and pumps are operating normally, whether the filters and nozzles are unobstructed or clogged, whether the liquid level is normal, whether the float balls are malfunctioning, etc. Also, we need to ensure that the concentration of the absorption and neutralization liquid is within the specified range. If any of the above issues are found, we should address them immediately. We must not perform forced operations, as this could affect the operation quality of the activated carbon adsorption box or damage the equipment. (2) Replacement cycle of activated carbon in the activated carbon adsorption box: Generally, activated carbon is used in the activated carbon adsorption box. There is a regular need for activated carbon regeneration or replacement. Under normal circumstances, we should calculate based on the factory working hours. For each eight-hour operation period, the de-adsorption treatment time of the activated carbon should be around three months. The processing cycle under this general situation can also be calculated in detail based on the actual usage of the activated carbon. The de-adsorption time should be adjusted according to the actual situation. Moreover, the activated carbon will lose its regeneration effect after two years of use; thus, we need to update and replace it. (3) Method for replacing activated carbon in the activated carbon adsorption box: To make the replacement of activated carbon during the operation process more convenient for us, the activated carbon is usually installed in an upward-inlet type, and the discharge port should be of a downward-outlet type. (4) Recovery of solvents: The solvents used in the waste gas treatment equipment are insoluble in water. They can be easily recovered by dissolving in water. The recovered solvents can be mixed with water and then added to the coal, or sent into the boiler for combustion. (5) Concentration of the mixed solution: The concentration of the NaOH and NaCl0 mixed solution in the first-stage absorption tower and the storage tank of activated carbon should be maintained at around 2% to 6%. When the concentration drops below 2%, the mixed solution needs to be added.