KR20050072342A - Nitrogen removal system by physical and chemical treatment - Google Patents

Abstract

The present invention not only effectively removes nitrogen from wastewater which causes eutrophication of water quality, but also solves the nitrogen problem by introducing advanced treatment facilities without significantly changing the conventional physical and chemical treatment facilities, and it is difficult to introduce biological treatment facilities. The present invention relates to a nitrogen treatment apparatus for wastewater generated from plating equipment and surface treatment equipment.

The present invention provides a nitrogen treatment apparatus by physicochemical treatment of wastewater generated in a plating facility or surface treatment facility, comprising: a raw water tank for accommodating wastewater to be treated; A redox and agglomeration reaction tank for transferring the wastewater contained in the raw water tank by a pump to redox and agglomerate; A precipitation tank for precipitating harmful metals or toxic substances in particulate form in the wastewater which has undergone redox reaction and agglomeration reaction tank; A treated water collecting tank for collecting the supernatant in the wastewater passed through the settling tank; An activated carbon adsorption tower for removing fine suspended solids of the wastewater not collected from the sedimentation tank in the wastewater collected by the treated water collection tank and then transported by a pump; An optional ion exchange resin tower capable of mainly removing nitrogen oxides not removed from the activated carbon adsorption tower by ion exchange with an ion exchange resin packed therein and reducing color, turbidity, and COD; A discharge tank for discharging the treated water ion-exchanged from the selective ion exchange resin tower into an aqueous system; One side is connected to the lower portion of the settling tank includes a dehydrator that can dewater the sludge precipitated through the settling tank.

Description

Nitrogen removal system by physical and chemical treatment

The present invention not only effectively removes nitrogen from wastewater which causes eutrophication of water quality, which is a phenomenon of deterioration of water quality caused by excessive inflow of organic substances (nitrogen or phosphorus) contaminated in stagnant water bodies. The present invention relates to a nitrogen treatment apparatus for wastewater generated from plating equipment and surface treatment equipment, which solves the nitrogen problem by introducing an advanced treatment equipment without significantly changing the physical and chemical treatment equipment.

Surface treatment facilities use chemicals such as nitric acid and ammonia. Alkali degassing can be removed in the case of ammonia, but since nitrate nitrogen and ammonia nitrogen coexist, and the oxidation process is at the forefront in the wastewater treatment process, most of the ammonia nitrogen is NO ₃ -N, NO _2- . It will change into the form of N. Nitrogen converted to NO ₃ -N, NO ₂ -N will be difficult to process by physicochemical methods. Nitrogen compounds in the form of NO ₃ -N and NO ₂ -N have to be removed by biological treatment process, but there is almost no biodegradable organic matter in the wastewater generated from surface treatment process, so there are few nutrients of microorganisms, It creates environment that microorganism is hard to survive.

1 is an overall schematic diagram of a surface treatment and plating wastewater treatment apparatus according to the prior art.

As shown in FIG. 1, a conventional wastewater treatment apparatus by physicochemical treatment includes: a raw water tank 31 for receiving wastewater to be treated; A redox and agglomeration reactor (33) for transferring the wastewater contained in the raw water tank (31) by a pump (32) for redox and agglomeration; A settling tank 34 for precipitating harmful metals or toxic substances in particulate form in the wastewater which has passed through the redox and coagulation reaction tank 33; A treated water collecting tank 35 for collecting the supernatant in the wastewater that has passed through the settling tank 34; A sand filtration tower (37 ') for removing fine suspended solids in the wastewater not collected in the settling tank (34) of the wastewater collected by the treated water collection tank (35) and then transported by the pump (36); An activated carbon adsorption tower 38 'capable of reducing color, turbidity, and COD by removing nitrogen oxides not removed from the sand filter tower 37'; A discharge tank 40 for discharging the treated water filtered out from the activated carbon adsorption tower 38 'into an aqueous system; One side is connected to the lower portion of the settling tank 34 is composed of a dehydrator 45 that can dewater the sludge precipitated through the settling tank (34).

The conventional wastewater treatment apparatus using a physicochemical treatment uses a sand filtration tower 37 'to remove fine suspended matter in the wastewater that has not been removed from the settling tank 34. The sand filtration tower has a low filtration efficiency. There was a flaw.

In addition, the conventional nitrogen treatment apparatus by the physicochemical treatment is equipped with an activated carbon adsorption tower (38 ') to reduce the chromaticity, turbidity, and COD not removed from the sand filter tower (37'), but the activated carbon adsorption tower is a one-time use Because of this, there is a disadvantage that the operating cost is very expensive because the activated carbon must be replaced continuously.

On the other hand, another conventional wastewater nitrogen, phosphorus high circulation treatment apparatus is disclosed in the Republic of Korea Utility Model Publication No. 20-0292230, Figure 2 is another conventional wastewater nitrogen, disclosed in the Utility Model Registration No. The overall schematic of the phosphorus advanced circulation treatment apparatus is shown.

According to the conventional wastewater nitrogen and phosphorus high circulation treatment apparatus described in this registered utility model, a raw water tank for accommodating wastewater 11 containing organic matter, nitrogen and phosphorus to be treated as shown in FIG. 12) Inorganic flocculant (16), fine media (17) and polymer flocculant (18) for adsorbing, absorbing and sedimenting organic matter, nitrogen and phosphorus from waste water (11) supplied by a pump from the raw water tank (12). 1 from the coagulation sedimentation tank 13 into which the coagulation sedimentation tank is injected at a constant concentration, the sludge precipitated from the coagulation sedimentation tank 13, and the coagulation sedimentation tank 13 again. Ion exchange resin tower 20 to selectively remove residual nitrogen not removed by flocculation and sedimentation from the discharged water discharged by primary treatment through the primary treatment tank 19 by ion exchange, and the corresponding resin tower 20 ) A discharge tank 21 for discharging the treated water ion exchanged from the water into a water system, and a conveying tank to return the concentrated waste liquid generated from the ion exchange resin tower 20 to the raw water tank 12 for reprocessing ( 22).

However, in such a conventional apparatus, since the ion exchange resin tower 20 is directly connected to the primary treatment water tank 19 without passing through the activated carbon adsorption column, it is insufficient in terms of filtration efficiency and is used when the concentration of nitrogen ions is high. Not only has a drawback in that a large amount of chemicals are required to regenerate and clean the ion exchange resin tower 20, but also two installations of the ion exchange resin tower 20 in succession have a disadvantage in that the cost of installation is increased. .

In addition, such a conventional apparatus is configured to return the concentrated nitrogen waste liquid which has passed through the ion exchange resin tower 20 to the raw water tank 12, and since there is no structure for reducing the nitrogen waste liquid, it is generated after concentrating the recycle waste liquid. There was a problem that can not be recycled pure water is a by-product.

Therefore, the present invention significantly replaces the sand filtration tower with the activated carbon adsorption tower in the conventional treatment process, and simultaneously replaces the activated carbon adsorption tower with the selective ion exchange resin tower to remove nitrogen oxides through the selective ion exchange resin, thereby greatly reducing color, turbidity, and COD. It is an object of the present invention to provide a treatment apparatus that reduces the number and prevents eutrophication of rivers.

Another object of the present invention is to provide a treatment apparatus for recycling pure water, which is a by-product generated when concentrating nitrogen adsorbed on a selective ion exchange resin tower, to process water.

Nitrogen treatment apparatus by physicochemical treatment of the present invention for achieving the above object, in the nitrogen treatment apparatus by physicochemical treatment for wastewater generated in the plating facility or surface treatment facility, to accommodate the wastewater to be treated Raw water tank for; A redox and agglomeration reaction tank for transferring the wastewater contained in the raw water tank by a pump to redox and agglomerate; A precipitation tank for precipitating harmful metals or toxic substances in particulate form in the wastewater which has undergone redox reaction and agglomeration reaction tank; A treated water collecting tank for collecting the supernatant in the wastewater passed through the settling tank; An activated carbon adsorption tower for removing fine suspended solids of the wastewater not collected from the sedimentation tank in the wastewater collected by the treated water collection tank and then transported by a pump; An optional ion exchange resin tower capable of mainly removing nitrogen oxides not removed from the activated carbon adsorption tower by ion exchange with an ion exchange resin packed therein and reducing color, turbidity, and COD; A discharge tank for discharging the treated water ion-exchanged from the selective ion exchange resin tower into an aqueous system; One side is connected to the lower portion of the settling tank includes a dehydrator that can dewater the sludge precipitated through the settling tank.

Here, a regeneration waste liquid storage tank for storing the regeneration waste liquid generated in the selective ion exchange resin tower; A multi-stage evaporator for transferring the regenerated waste liquid stored in the regenerated waste liquid storage tank to a slurry state; A evaporator concentrator pure water recovery tank connected to the multi-stage evaporator to collect water evaporated in the multi-steam evaporator and recycle to process water; By connecting the other side of the dehydrator to the multi-stage evaporator, it is preferable that the slurry made in the multi-stage evaporator can be dehydrated.

In addition, the ion exchange resin of the selective ion exchange resin column is preferably present in the form of an adsorber of R (resin) -Cl before the adsorption.

In addition, it is preferable that the selective ion exchange resin column is charged with a regenerant to return the ion exchange resin, which is filled in the ion exchange resin column and saturated with nitrogen ions, to the original resin form having an R-Cl adsorber form. .

In addition, the regenerant is preferably salt (NaCl).

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

Figure 3 of the accompanying drawings is a schematic diagram of a nitrogen treatment apparatus by a physicochemical treatment according to the present invention.

Nitrogen treatment apparatus by physicochemical treatment according to a preferred embodiment of the present invention is a nitrogen treatment apparatus by physicochemical treatment for wastewater generated in the plating or surface treatment equipment, raw water tank for receiving the waste water to be treated (31); A redox and agglomeration reactor (33) for transferring the wastewater contained in the raw water tank (31) by a pump (32) for redox and agglomeration; A precipitation tank 14 for precipitating harmful metals or toxic substances in particulate form in the wastewater which has passed through the redox and flocculation reaction tank 33; A treated water collecting tank 35 for collecting the supernatant in the wastewater that has passed through the settling tank 34; An activated carbon adsorption tower (37) for removing fine suspended solids in the wastewater not collected in the sedimentation tank (34) of the wastewater collected by the treated water collection tank (35) and then transported by the pump (36); An selective ion exchange resin tower 38 capable of mainly removing nitrogen oxides not removed from the activated carbon adsorption tower 37 and reducing chromaticity, turbidity, and COD by ion exchange with an ion exchange resin packed therein; A discharge tank 40 for discharging the treated water ion-exchanged from the selective ion exchange resin tower 38 into an aqueous system; One side is connected to the lower portion of the settling tank 34 includes a dehydrator 45 that can dewater the sludge precipitated through the settling tank 34.

Here, sludge refers to a sediment produced during sewage treatment or water purification, and is also referred to as sludge. The slurry used hereinafter is a mixture of a solid and a liquid or fine solid particles suspended in water. ) Suspension.

In addition, chemical oxygen demand (COD), or chemical oxygen demand, refers to the amount of chemical oxygen consumed to oxidize and purify pollutants such as organic matter by oxidizing agent in parts per million (mg) or mg / As indicated by l, the more water is contaminated, the more organic matters. Therefore, the amount of oxygen required for oxidative decomposition also increases. Accordingly, the greater the COD value, the more severe the contamination of water.

In general, wastewater generated from plating processes mainly contains cyanide (CN), chromium, acids, and alkali-based components.

In the wastewater containing such components, cyan is oxidized at pH 10 or more using an oxidizing agent, NaOCl, in the redox and agglomeration reactor 33 and finally decomposed into CO ₂ and N ₂ .

In addition, the chromium contained in the waste water is divided into hexavalent chromium and trivalent chromium. Trivalent chromium is precipitated well as a hydroxide, but hexavalent chromium is not precipitated and is dissolved. Therefore, since the hexavalent chromium can be reduced to trivalent chromium to precipitate the hydroxide, sulfur compounds such as NaHSO ₃ are mainly introduced into the redox and agglomeration reactor 33 to reduce hexavalent chromium to trivalent chromium.

In this way, when the oxidized and reduced wastewater is above the pH neutral, particles are generated. Such a process is called neutralization, and when a coagulant is added to the redox and agglomeration reactor 33 to sink the particles in the neutralized liquid, the particles are aggregated together. The flocculant used for flocculation may vary depending on the environment, such as waste water, properties, and factories.

The settling tank 14 is transported in the wastewater containing the aggregated particles through the oxidation, reduction and coagulation reaction as described above in the redox and coagulation reaction tank 33 to sink the aggregated particles.

The activated carbon adsorption tower 37 of the present invention replaces the sand filter of the physicochemical wastewater treatment apparatus of the prior art, and is installed for the purpose of removing fine suspended solids in the wastewater that has not been removed from the sedimentation tank 34. Backwash can restore the original condition. Therefore, the activated carbon adsorption tower 37 of the present invention does not cause the problem of continuing to replace the activated carbon as described in the prior art activated carbon adsorption tower. Since the above backwashing method is well known, a detailed description thereof will be omitted.

Then, the ion exchange resin of the selective ion exchange resin column 38 is that the ion affinity (NO ₃ ^- -N or ^{_{NO 2 - -N)> SO 4}} 2-> HCO 3 -> Cl - is in the order of it NO ₃ ^- is able to selectively adsorb nitrogen in the form -N ^- -N or NO _2.

When the ion exchange resin of the selective ion exchange resin tower 38 is expressed as R (resin), the ion exchange resin is initially present in the form of R-Cl, and nitrite and nitrate nitrogen pass through the ion exchange resin. The ion exchange resin is changed to R-NO ₃ , R-NO ₂ . That is, chlorine (Cl) ions and NO ₃ , NO ₂ ions are replaced. As a result, nitrogen ions are removed from the wastewater passing through the ion exchange resin. If the substitution continues as described above and the ion exchange resin is saturated, that is, if all of the ion exchange resins are replaced with nitrogen ions, the nitrogen ions contained in the waste water can no longer be replaced. The waste water will be discharged as it is without being removed.

In the case described above, when the regenerant 39 is introduced into the selective ion exchange resin tower 38 in which nitrogen ions are saturated and adsorbed, the ion exchange resin of the ion exchange resin tower 38 is in the form of a resin having the original adsorber. It can be returned to the state that can be used continuously, but it is preferable to use salt (NaCl) as the regenerant 39, but is not limited thereto.

When salt (NaCl) is selected as the regenerant 39 and the salt is added to the ion exchange resin of the selective ion exchange resin tower 38 in which nitrogen ions are saturated and adsorbed, R-NO ₃ , R-NO ₂ + NaCl → R-Cl + Na + + NO 3 - or No 2 - a nitrogen ion concentration over the course of the are forced out from the ion exchange resin.

On the other hand, according to another embodiment of the present invention, the present invention and the regeneration waste liquid storage tank 41 for storing the regeneration waste liquid generated in the selective ion exchange resin tower 38 in the configuration according to a preferred embodiment of the present invention described above and ; A multi-stage evaporator (44) for transferring the regeneration waste liquid stored in the regeneration waste liquid storage tank (41) to a slurry state; A evaporator concentrator pure water recovery tank 42 connected to the multi-evaporation concentrator 44 to collect water evaporated in the multi-evaporation concentrator 44 and to recycle the process water; By connecting the other side of the dehydrator 45 to the multi-stage evaporator 44 is characterized in that the slurry made in the multi-stage evaporator 44 can be dehydrated.

Here, the regeneration waste liquid refers to an ion exchange resin in which a nitrogen-saturated ion exchange resin is charged by adding a regenerant 39 to the selective ion exchange resin tower 38 and filled in the ion exchange resin tower 38. It refers to the waste liquid generated according to the input of the regenerant 39 when it is returned to the original resin form can be conveyed by the pump 43 to make a slurry in the multi-stage evaporator 44 to discard.

In addition, the waste water contained in the raw water tank is transferred, the activated carbon adsorption tower 37 transfers the waste water from which the fine suspended solids are removed, and the regeneration waste liquid stored in the regeneration waste liquid storage tank 41 is respectively pump 32, 36, 43).

Looking at the operation and treatment process of the nitrogen treatment apparatus by the physicochemical treatment of the present invention having the configuration as described above are as follows.

In the plating process or the surface treatment process, waste water in the state of containing heavy metals and nitrogen at the time of etching or washing is generated. In the present invention, it is possible to treat the wastewater containing the heavy metal components and nitrogen generated in the plating process or surface treatment process as described above,

Such wastewater is accommodated in the raw water tank 31 and transported by a pump to perform redox and agglomeration reactions in the redox and agglomeration reaction tanks 33, and the harmful metals in the wastewater that have passed through the redox and agglomeration reaction tanks 33 Toxic substances are precipitated in particulate form in the settling tank 34, and then fine suspended solids of the wastewater not removed from the settling tank 34 are removed by the activated carbon adsorption tower 37.

The treated water collecting tank 35 collects the supernatant of the wastewater which has passed through the settling tank 34 as described above, and collects the wastewater from which the fine suspended solids have been removed from the activated carbon adsorption tower 37 by a pump, and collects the activated carbon adsorption tower. Wastewater having passed through (37) is ion-exchanged in the selective ion exchange resin tower (38) with the ion exchange resin packed inside the resin tower (38) to remove nitrogen oxides not removed from the activated carbon adsorption tower (37). It is possible to greatly reduce turbidity and COD, and thus the treated water ion-exchanged from the selective ion exchange resin tower 38 may be discharged into the water system through the discharge tank 40.

The regeneration waste liquid generated by the input of the regenerant 39 in the selective ion exchange resin tower 38 is stored in the regeneration waste storage tank 41, and the regeneration waste liquid stored in the regeneration waste storage tank 41 is transferred by a pump. It may be made in a slurry state in the multi-stage evaporator 44.

And, the sludge precipitated through the settling tank 34 and the slurry made in the multi-stage evaporator 44 can be dewatered in the dehydrator 45.

Here, the treated water can be maintained at a level of 1 NTU for turbidity and less than 10 ppm for COD.

As described above, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention should be construed that all changes or modifications derived from the meaning and scope of the appended claims and their equivalents, rather than the detailed description, are included in the scope of the present invention.

The present invention according to the configuration as described above by replacing the sand filtration tower with the activated carbon adsorption tower in the conventional treatment process and at the same time by replacing the activated carbon adsorption tower with the selective ion exchange resin tower to remove the nitrogen oxide through the selective ion exchange resin Color, turbidity and COD can be significantly reduced to prevent eutrophication of rivers.

In addition, according to the present invention there is an effect that can be recycled into the process water pure water, which is a by-product generated when the nitrogen adsorbed on the selective ion exchange resin tower.

1 is an overall schematic diagram of a surface treatment and plating wastewater treatment apparatus according to the prior art;

2 is an overall schematic view of another conventional wastewater nitrogen, phosphorus high circulation treatment apparatus;

3 is a schematic diagram of an apparatus for treating nitrogen by physicochemical treatment according to the present invention.

* Description of the symbols for the main parts of the drawings

11: wastewater 12: raw water tank

13: flocculation sedimentation tank 14: conveying pump

16: Inorganic Coagulant 17: Porous Fine Media

18: polymer flocculant 19: primary treatment tank

20: ion exchange resin tower 21: discharge tank

22: return tank 31: raw water tank

32, 36, 43: pump 33: redox and flocculation reactor

34: sedimentation tank 35: physicochemical treated water collection tank

37 ': sand filtration tower 37: activated carbon adsorption tower

38 ': activated carbon adsorption tower 38: selective ion exchange resin tower

39: regenerant 40: discharge tank

41: ion exchange resin regeneration waste liquid storage tank 42: evaporative concentrator pure water recovery tank

44: multi-stage evaporator 45: dehydrator

Claims (5)

In the nitrogen treatment apparatus by physicochemical treatment of wastewater generated in the plating facility or surface treatment facility, A raw water tank 31 for receiving waste water to be treated; A redox and agglomeration reactor (33) for transferring the wastewater contained in the raw water tank (31) by a pump (32) for redox and agglomeration; A precipitation tank 14 for precipitating harmful metals or toxic substances in particulate form in the wastewater which has passed through the redox and flocculation reaction tank 33; A treated water collecting tank 35 for collecting the supernatant in the wastewater that has passed through the settling tank 34; An activated carbon adsorption tower (37) for removing fine suspended solids in the wastewater not collected in the sedimentation tank (34) of the wastewater collected by the treated water collection tank (35) and then transported by the pump (36); An selective ion exchange resin tower 38 capable of mainly removing nitrogen oxides not removed from the activated carbon adsorption tower 37 and reducing chromaticity, turbidity, and COD by ion exchange with an ion exchange resin packed therein; A discharge tank 40 for discharging the treated water ion-exchanged from the selective ion exchange resin tower 38 into an aqueous system; One side is connected to the lower portion of the settling tank 34, nitrogen treatment apparatus by a physicochemical treatment, characterized in that it comprises a dehydrator 45 for dewatering the sludge precipitated through the settling tank (34). The method of claim 1, A regeneration waste liquid storage tank 41 for storing the regeneration waste liquid generated by the selective ion exchange resin tower 38; A multi-stage evaporator (44) for transferring the regeneration waste liquid stored in the regeneration waste liquid storage tank (41) to a slurry state; A evaporator concentrator pure water recovery tank 42 connected to the multi-evaporation concentrator 44 to collect water evaporated in the multi-evaporation concentrator 44 and to recycle the process water; Connecting the other side of the dehydrator (45) to the multi-stage evaporator (44) by dehydrating the slurry produced in the multi-stage evaporator (44) characterized in that the nitrogen treatment apparatus by physicochemical treatment. The nitrogen treatment apparatus according to claim 1, wherein the ion exchange resin of the selective ion exchange resin tower (38) exists in the form of an adsorber of R (resin) -Cl before adsorption is performed. The ion exchange resin of claim 1, wherein a regenerant 39 is added to the selective ion exchange resin tower 38 and filled in the ion exchange resin tower 38 to saturate and adsorb nitrogen ions. Nitrogen treatment apparatus by physicochemical treatment, characterized in that to return to the original resin form. The nitrogen treatment apparatus according to claim 4, wherein the regenerant is salt (NaCl).