JPH02164500A - Water purifying treatment apparatus - Google Patents

Abstract

PURPOSE:To perform water purifying treatment capable of coping with the deterioration of the quality of raw water for tap water by combining a biological oxidation process, an immobilized nitrification process, a reverse osmosis membrane permeation process and a deionizing process. CONSTITUTION:The removal of the org. substance in raw water and the nitrification of ammoniacal nitrogen are performed in the biological oxidation basin 2 and the immobilized nitrification tank 3, wherein nitrifying bacterial are immobilized, both of which are arranged next to a sand sedimentation basin 1 and the treated raw water is passed through a water purifying process consisting of a usual rapid stirring basin 4, a sedimentation basin 5 and a filter basin 6 to remove the suspended substance in the raw water and subsequently transmitted through a reverse osmosis apparatus 7 to remove the soluble org. substance and inorg. ion in the raw water and sterilized by chlorine from a chloride injection device 8 to be distributed from a water distribution basin 9. The non-transmitted conc. water of the reverse osmosis apparatus 7 is deionized by a deionizing device to be returned to the raw water and the ion adsorbed by an ion exchange resin is washed by a washing tank 11 and lime is added to the washing solution in said tank 11 to coprecipitate a heavy metal ion while the neutralized supernatant liquid is supplied to an immobilized denitrification tank 12 to change a conc. nitrate ion to nitrogen gas before being discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a water purification treatment device capable of high-level purification treatment.

B1 Overview of the Invention The water purification device of the present invention removes organic matter from raw water and nitrifies ammonia nitrogen using a fixed-bed biological oxidation pond and an immobilization tank in which nitrifying bacteria are immobilized on superabsorbent resin. The water undergoes a normal water purification process consisting of rapid stirring, sedimentation, and filtration to remove suspended solids, and then passes through a reverse osmosis device to remove dissolved organic matter and inorganic ions, sterilizes it with chlorine, and discharges it from the distribution reservoir. On the other hand, the non-permeated concentrated water in the reverse osmosis equipment is deionized with an ion exchange resin and returned to the raw water, and the ions adsorbed on the ion exchange resin are washed, and lime is added to the washed liquid to remove heavy metal ions. Co-precipitated sludge is removed, and the supernatant water is placed in a denitrification tank with denitrification bacteria immobilized on superabsorbent resin, and methanol is supplied to convert nitrate ions into nitrogen gas before being discharged. This is what I did.

C1 Conventional technology In Japan, the demand for water supply is increasing year by year.
Water supply capacity is limited, making it difficult to obtain high-quality water sources. For this reason, many places use river surface water as their water source, causing problems such as off-flavors and trihalomethane formation. On the other hand, the need for safe and delicious water is increasing, and advanced water purification treatment is required.

Current water purification methods mainly involve removing suspended solids and sterilizing water, and are not very effective in removing dissolved substances. This has resulted in problems caused by soluble organic matter, such as off-flavors and trihalomethane formation.

When the ammoniacal nitrogen concentration of raw water increases due to water eutrophication, chlorine consumption increases and trihalomethane production increases. The current general water purification process is shown in Figure 2, but if the quality of the raw water is poor, advanced treatment is required.

Ru.

Currently, there are the following advanced processing methods.

Biological oxidation and activated carbon adsorption are effective for removing soluble organic matter, and ozone treatment is effective for removing off-flavors, tastes, and sterilization. Also,
There is an ion exchange method for removing soluble inorganic substances, and a reverse osmosis method for removing soluble substances (inorganic substances + organic substances).

D9 Problems to be solved by the invention Biological oxidation has the effect of not only removing six organic substances, but also nitrifying ammonia and reducing chlorine consumption, but it has the disadvantage that the purification ability, especially the nitrification ability, decreases when the water temperature drops. . Also,
Ozone treatment, activated carbon adsorption, and ion exchange methods are expensive.

Reverse osmosis is effective in removing soluble substances and is a promising method for the future, but there are problems in processing concentrated water that is generated in large quantities. As described above, each method has its advantages and disadvantages, and there is a limit to the improvement in treated water quality even if adopted alone.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide a water purification device that can cope with deterioration in the quality of raw water from tap water. .

61 Means for Solving the Problems The water purification treatment apparatus of the present invention comprises: a settling basin into which raw water is introduced; a fixed bed type biological oxidation pond in which activated sludge is immobilized into which water from the settling basin is introduced; An immobilized nitrification tank in which nitrifying bacteria are immobilized on superabsorbent resin into which the treated water from the biological oxidation pond is introduced, a rapid stirring pond into which the treated water from this immobilized nitrification tank is introduced, and stirring in this rapid stirring pond. A sedimentation tank into which water is introduced, a filtered oil into which water from the settling tank is introduced, a reverse osmosis device into which water from this filtered oil is introduced, and water permeated through the reverse osmosis membrane of this reverse osmosis device. A water distribution reservoir in which a an ion device, a cleaning liquid tank in which lime is added to the liquid used to wash the ion exchange resin, and an immobilized denitrification tank in which immobilized denitrifying bacteria are put in the supernatant water of the cleaning liquid tank, methanol is supplied as a substrate, the denitrification is performed, and the water is discharged. It is more than that.

After coarse turbidity is removed from F1 action water raw water in a settling pond, organic matter is removed by aerobic microorganisms in a biological oxidation pond, and then ammonia is nitrified in a fixation nitrification tank.

This water undergoes a normal water purification process consisting of a rapid stirring pond, settling basin, and filtered oil to remove suspended matter.

This water passes through the reverse osmosis membrane of the reverse osmosis device, removes dissolved organic matter and ions, and is sterilized with chlorine before entering the water distribution reservoir.

After ions are removed from the concentrated water that has not passed through the reverse osmosis membrane, it is returned to the raw water of the tap water and enters the settling basin again, where the water purification treatment is performed.

When the ion exchange resin in the deionization device becomes saturated and its deionization ability decreases, it is washed, and lime is added to the washing liquid in the washing liquid tank to co-precipitate heavy metal ions.

The supernatant water is discharged after converting concentrated nitrate ions into nitrogen gas in a fixed denitrification tank.

G. Example An embodiment will be described with reference to FIG.

The raw water from the water supply is passed through a settling pond (2) to remove coarse turbidity, and then enters the biological oxidation pond (2). The biological oxidation pond 2 has aerobic microorganisms (poor sludge) immobilized on a fixed bed, and aeration is performed to remove organic matter by the microorganisms and nitrify ammonia by nitrifying bacteria in the activated sludge.

Next, ammonia is nitrified in the immobilization nitrification tank 3.

The immobilized nitrification tank 3 contains immobilized nitrifying bacteria that have been selectively cultured in an ammonia-based medium and is comprehensively immobilized with a super absorbent resin, calcium carbonate, and calcium chloride, and performs airage gin to achieve biological oxidation. In pond 2, unreacted ammonia nitrogen and nitrite nitrogen generated by incomplete nitrification change to nitrate nitrogen. Ammonia nitrogen reacts with chlorine, resulting in significant chlorine consumption, but nitrate nitrogen does not react with chlorine, thereby eliminating the need for a pre-chlorination device (FIG. 1) in the normal purification process.

From the water treated in the nitrification tank 3, suspended matter is mainly removed in a rapid stirring tank 4, a sedimentation tank 5, and a filtered oil 6, which are normal water purification processes.

Next, the water from the filtration oil 6 is passed through the reverse osmosis membrane of the reverse osmosis device 7 to remove soluble organic matter and ions, sterilized with chlorine by the chlorine injection device 8, and sent to the distribution reservoir 9. Water will be distributed.

On the other hand, the concentrated water that does not pass through the reverse osmosis membrane in the reverse osmosis device 7 has its ions removed by the deionization device IO, is returned to the tap water, is mixed with the raw water, and then enters the settling tank 1 again for water purification treatment.

When the ion exchange resin in the deionization device 10 becomes saturated and the deionization ability decreases, cleaning is performed. The washed liquid is neutralized by adding lime in the washing tank 11 to coprecipitate heavy metal ions, and the supernatant liquid is immobilized in the denitrification tank 12, where the concentrated nitrate ions are converted into nitrogen gas and denitrified, and then used in rivers, etc. Drain to. The immobilization denitrification tank 12 contains entrapping immobilization of denitrification bacteria selectively cultured in a denitrification bacteria medium using a super absorbent resin, calcium carbonate, and calcium chloride, and is supplied with methanol as a substrate.

H2 Effects of the Invention Since the present invention is configured as described above, it produces the following effects.

■ Biological oxidation and nitrification reduce organic matter and ammonia nitrogen in raw water, making it possible to reduce the amount of chlorine injection during water purification. As a result, the amount of trihalomethane produced, which is harmful to health, can be reduced.

■ Since nitrifying bacteria are autotrophic, their growth rate is slow, and their nitrification activity decreases at low water temperatures, the nitrification rate often decreases in winter with the normal activated sludge method, but immobilization reduces the nitrification rate. Since the concentration is high, the nitrification rate does not decrease even in winter, and the ammonia concentration can be lowered. Moreover, this allows stable water purification treatment with little change in the amount of chlorine injected.

■ With reverse osmosis, there is a problem with processing large amounts of unpermeated concentrated water, but by deionizing this and returning it to the raw water supply, the water can be purified and used.

■ The water quality of purified water is higher than that of conventional water as soluble organic matter and ions are removed.

■ Nitrate nitrogen and harmful heavy metals, which cause trophication, are removed.

■ Secondary treatment of sewage It can be used as a tertiary treatment process such as denitrification, dephosphorization, removal of suspended solids, soluble organic matter, and inorganic ions.

[Brief explanation of the drawing]

FIG. 1 is a water purification process diagram of the water purification apparatus of the present invention, and FIG. 2 is a water purification process diagram of a conventional water purification apparatus.

Claims (1)

[Claims] (1) A settling basin into which raw water from the water supply is introduced; a fixed-bed biological oxidation pond with immobilized activated sludge into which water from the settling basin is introduced; and a super absorbent resin into which treated water from the biological oxidation pond is introduced. An immobilized nitrification tank in which nitrifying bacteria are immobilized, a rapid stirring tank into which the treated water from this nitrification tank is introduced, a settling tank into which the agitated water from this stirring tank is introduced, and a settling tank in which the water from this settling tank is A filtration pond to be introduced, a reverse osmosis device to which water from this filtration pond is introduced, a distribution reservoir to which reverse osmosis membrane permeated water of this reverse osmosis device is introduced, and chlorine injected into the reverse osmosis membrane permeated water. a chlorine injection device; a deionization device using an ion exchange resin that removes ions from the concentrated water that has not permeated through the reverse osmosis membrane and returns it to the tap raw water; and a deionization device that uses an ion exchange resin to remove ions from the concentrated water that has not permeated through the reverse osmosis membrane and to add lime to the liquid from which the ion exchange resin has been washed and stir it for sedimentation. A water purification treatment device comprising: a cleaning liquid tank that contains immobilized denitrifying bacteria in supernatant water of the cleaning liquid tank, supplies methanol as a substrate, denitrifies the water, and discharges the water.