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How to deal with excessive fluoride in drinking water


1. Process selection for defluoridation of drinking water

At present, the methods of treating groundwater fluoride at home and abroad include: electrochemical method, coagulation precipitation method, ion exchange method and other different processes. Different processes are used in different environments and occasions, each with their own advantages and disadvantages.

The process principle of the coagulation sedimentation method is to add the coagulant aluminum salt to the raw water to remove the fluoride ion in the water after mixing, flocculation and precipitation. After this process, a large amount of precipitated sludge will be produced. In addition, using aluminum salt as a coagulant will introduce a large amount of dissolved aluminum and affect human health. Therefore, this method is mainly used for the treatment of fluorine-containing wastewater, not suitable for drinking water treatment.

The technical principle of electrodialysis chemical method is that under the action of an external electric field, negatively charged fluoride ions and positively charged ions are moved to the anode and cathode directions through anion and cation exchange membranes by selective permeation membranes, respectively. a method. The process requires a lot of electricity, and the anode and cathode by-products are difficult to control, posing a potential threat to human health.

The process principle of ion exchange method is to use the resin bed formed by anion resin to carry out ion exchange with raw water containing fluoride ion, that is, the fluoride ion is exchanged and adsorbed by the chloride ion or bicarbonate ion of the resin, so as to achieve the purpose of removing fluoride. Relatively speaking, the ion exchange process gradually slows down with the decrease of ion concentration and the increase of resin saturation, and the time is prolonged. For raw water with high fluoride concentration, generally above 20mg/L, this process has good economy and practicability. The application of this process to drinking water treatment shows some deficiencies, mainly because the concentration of fluoride in raw water is generally in the range of 2-10mg/L, and there is no professional management; resin regeneration is relatively complex; regeneration of raw materials is not easy to manage; it will produce salt content Regeneration waste liquid with high amount; waste liquid contains strong alkali, which is difficult to dispose. Therefore, this process is more suitable for the treatment of high-concentration fluoride in the industrial environment, and it is difficult to popularize it in the drinking water treatment industry.

Therefore, Beijing 322 Water Equipment Technology Development Co., Ltd. designed and developed a new type of fluoride excess-proportional method treatment equipment based on the disadvantages of the ion exchange method, combined with the characteristics of rural water supply and previous engineering experience. Method for RO Membrane Fluoride Treatment Equipment.

The equipment can stably produce qualified drinking water, which is not only different from traditional RO membrane equipment, but also achieves or even better than the ion exchange process. Not only that, the water production effect of this process can be precisely set, the degree of automation is high, it is more suitable for centralized water supply in high-salt areas, and the cost of the operation process is low, and the rate of wastewater discharge is low.

2. Introduction of drinking water proportional RO membrane fluoride treatment equipment

The fluoride exceeding standard-proportional method treatment equipment is a drinking water purification treatment equipment specially developed for treating the raw water with excessive fluoride in the self-provided well (or surface water) as qualified drinking water after treatment.

The full name of fluoride excess-proportional method treatment equipment is: drinking water proportional method RO membrane fluoride treatment equipment. The working principle of the equipment is: use the proportional method automatic mixing system as the core system; the RO membrane fluoride separation system removes most of the fluoride in the raw water exceeding the standard (fluoride content ≤ 0.2mg/L), using PID control technology, the The raw water of the proportional method distribution system is automatically mixed in the drinking water proportional method mixing system according to the set target (national standard fluoride concentration ≤ 1.2mg/L), thereby producing qualified drinking water with fluoride concentration that meets the national standard .

3. Performance characteristics of drinking water proportional method RO membrane fluoride treatment equipment:

1. No need for professional operators, if a fault is found, it can be automatically restored after power failure.

2. The operating cost is more economical, and there is no need for chemical regeneration.

3. Daily operation and operation and maintenance are simpler.

4. The water production is stable and can be adjusted automatically.

5. The output of wastewater is low and no professional treatment is required.