JP3323012B2 - Water quality analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water quality analyzer for analyzing water quality using high performance liquid chromatography in a water quality test for easily grasping the treatment status of each treatment step of a water treatment facility represented by a water supply facility. In particular, the present invention relates to a water quality analyzer capable of simultaneously analyzing the whole dissolved substance and dissolved organic matter at the same time.

[0002]

2. Description of the Related Art In the field of water treatment, various characteristics such as raw water for tap water such as rivers, lakes and mars, groundwater, various kinds of water for environmental use, drainage, treated water in each treatment step of water supply facilities, discharged water and drinking water, and bottled water. There is water with In these water treatment facilities, organic matter removal is one of the important treatments, and there are a wide variety of organic matter items and measurement methods that can be removed by physicochemical and biological treatment methods. Organic matter is roughly divided into floating organic matter and dissolved organic matter, and its abundance is measured from the measurement of the total amount of floating organic matter and dissolved organic matter to the measurement of the low-concentration trace amount of dissolved organic matter. Understanding is important and essential for the evaluation of water treatment facilities.

[0003] As a representative index of the amount of organic matter, measurement of COD, BOD, and TOC is generally considered. However, when a trace amount of dissolved organic matter of several tens of ppb is targeted, the measurement limit of these methods is exceeded. Accuracy is required. In addition, although these methods are automated, there are many complicated devices and a large amount of sample is required. Furthermore, in the measurement of low-concentration trace dissolved organic substances by a TOC measuring device or gas chromatograph mass spectrometry, pretreatment such as concentration at a laboratory level or extraction of a solvent is required, and there is a problem in reproducibility and measurement accuracy.

Therefore, a water quality analyzer using high performance liquid chromatography, which can measure dissolved substances in a relatively short time, has begun to be used in recent years. This water quality analyzer is composed of a liquid chromatography section consisting of a column and a developing solvent for fractionating a sample according to molecular weight, and a detection section consisting of a conductivity detector, a refractive index detector, an ultraviolet absorption detector, and a fluorescence detector. In particular, salts and buffer solutions are used as developing solvents to maintain the characteristics of gel filtration packed columns.

[0005] In such a water quality analyzer, even when the electric conductivity or the refractive index, which is an index of the entire dissolved substance, is detected, the concentration of the dissolved inorganic substance in the developing solvent is higher than the concentration of the dissolved substance in the sample. Measurement cannot be performed.

On the other hand, when a salt or a buffer solution is used as a developing solvent, it is possible to measure only dissolved organic substances. For example, the absorption intensity at a specific wavelength can be measured using an ultraviolet absorption detector, and can be used as an index of a dissolved organic substance. This method is an example of an effective analysis method that can predict the abundance of a typical dissolved organic substance having an unsaturated bond in the molecular structure, and can measure the ppb level. However, since this analysis method responds only to a substance having an ultraviolet absorption property, it cannot show the entire dissolved organic matter.

FIG. 10 shows an example of a water quality analyzer using such high performance liquid chromatography. As shown in FIG. 10, the mobile phase salt and buffer solution in the tank 1 are sent to the sample injector 4 by the liquid sending pump 3, and together with the sample injected by the syringe 5, together with the aqueous gel filtration packed column 6. Where the molecular weight fractionation occurs. The fractionated dissolved substances are sent to the ultraviolet absorption detector 10 in order of decreasing molecular weight, where specific dissolved organic substances are detected, and a chromatogram is recorded in the recorder 9.

[0008]

Regarding the dissolved substances in each step of the water treatment facility, dissolved organic matter accounts for the majority in sewage and wastewater treatment, and dissolved inorganic matter accounts for the majority in tap water and industrial water. In evaluating such treated water in water and sewage facilities, it is necessary to grasp the overall characteristics of dissolved substances including inorganic substances as well as dissolved organic substances. In this case, when a salt or a buffer solution is used as a developing solvent, both detection of a dissolved organic substance such as ultraviolet absorption and fluorescence and detection of the entire dissolved substance such as electric conductivity and refractive index cannot be performed simultaneously. Further, depending on the pH, the salt and the developing solvent of the buffer solution affect dissolved substances in the sample, and it is difficult to perform highly accurate measurement.

The present invention has been made in consideration of the above points, and simultaneously and simultaneously enhances the characteristics of the dissolved substance as a whole, including inorganic and organic substances, and the characteristics of the dissolved organic substance, which is a main operating factor in water treatment. It is an object of the present invention to provide a water quality analyzer capable of detecting with high sensitivity.

[0010]

SUMMARY OF THE INVENTION The present invention provides an aqueous gel filtration packed column for separating substances in order of molecular weight,
A developing solvent supply device for transferring the developing solvent to the aqueous gel filtration packed column side, and a sample injection device for injecting a sample into the developing solvent transferred from the developing solvent supply device to the aqueous gel filtration packed column side, A water quality analyzer comprising using pure water as a developing solvent, and a detector for a dissolved organic substance and a detector for the entire dissolved substance disposed in series on the downstream side of the aqueous gel filtration packed column. .

[0011]

The pure water as the developing solvent is transferred from the developing solvent supply device to the column filled with aqueous gel filtration, and a sample is injected into the developing solvent from the sample injection device. The sample is separated in a water-based gel filtration packed column in the order of molecular weight, and the separated substances are detected by a detector for dissolved organic substances and a detector for all dissolved substances.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 8 show a first embodiment of the water quality analyzer according to the present invention.

In FIG. 1, a water quality analyzer includes a first solution storing, for example, a 0.1 M Na ₂ SO ₄ solution (regenerating solution).
A storage tank 1A and a second storage tank 2 for storing pure water (developing solvent) are provided. The first storage tank 1A and the second storage tank 2 are arranged in parallel with each other and connected to the liquid feed pump 3 respectively. Have been.

The liquid sending pump 3 further includes a sample injector 4, a water-based gel filtration packed column 6 having a filter material as a base material and separating substances in order of molecular weight, and a differential refractive index for detecting the entire dissolved substance. A total 7, and a fluorometer 8 for detecting dissolved organic matter are directly connected in sequence.

A recorder 9 for creating a chromatogram is connected to the differential refractometer 7 and the fluorometer 8.

The sample injector 4 has a sample inlet 4A and a switching valve 4 for switching between sample injection and developing solvent.
B and a sample loop container 4C in which the amount of the dissolved substance of the sample is considered in advance. The capacity of the sample loop container 4C is determined in proportion to the amount of the dissolved substance. For example, 500 μl for water purification and 500 μl for sewage. 20 μl is used. A syringe 5 having a 0.45 μm filter is connected to the sample injection port 4A, and an excess sample injected from the syringe 5 is discharged out of the system as an excess sample waste liquid. The sample injector 4 and the syringe 5 constitute a sample injection device.

Next, the operation of this embodiment having the above configuration will be described.

First, pretreatment (regeneration) of the column is performed to stabilize the water quality analyzer. In the first storage tank 1A, a Na ₂ SO ₄ solution as a regenerating solution is ultrasonically degassed for 30 minutes or more under reduced pressure, and then the solution is supplied to the solution sending pump 3 at a flow rate of 0.5 ml /
The sample flows through the sample injector 4 and the column 6 filled with aqueous gel filtration for at least 4 hours at a minimum. Next, the second
Pure water 2 which has been degassed in the same manner in the storage tank 2 is supplied by the liquid sending pump 3 at a flow rate of 0.5 ml / min for 3 hours, the sample injector 4 and the column 6 filled with aqueous gel filtration.
And then flow for 1 hour at a flow rate of 1.0 ml / min. Thus, the regeneration of the column 6 is performed.

Next, if necessary, the column separation ability is confirmed with the standard sample and the sensitivity of the detector is corrected. For example, an aqueous solution containing polyethylene glycol or pyrenesulfonic acid having different average molecular weights is injected from the syringe 5 into the sample injector 4, and the sensitivity of the differential refractometer 7 and the fluorometer 8 is corrected.

Here, another organic substance may be used as the standard substance.

Next, the sample is measured. First, a sample is injected from the syringe 5 into the sample injector 4 from the sample injection port 4A. The sample is stored in the sample loop container 4C from the sample inlet 4A, and the excess sample is discharged out of the system as excess sample waste liquid. Next, when the switching valve 4B is switched,
A required amount of the sample retained in the sample loop container 4C is led to a packed column 6 based on an aqueous gel filtration material together with pure water 2 as a developing solvent sent by a liquid sending pump 3. , And fractionated in order from the one with the largest molecular weight.

The dissolved substance fractionated from the high molecular to the low molecular due to the difference in the outflow time is detected by the differential refractometer 7 and the fluorometer 8 and the chromatogram is simultaneously prepared by the recorder 9.

As the aqueous gel filtration packed column 6, a packed column generally made of a hydrophilic silica gel or the like having a three-dimensional network structure is used. However, since the surface of the column base material is hydrophilic, has hydroxyl groups and has some ion exchange ability, when pure water is used as a developing solvent, the resolution decreases with time due to interaction with ions.

The present inventor has reported that Na ₂
If the pure water is used as a developing solvent for about 2 hours or more after the regeneration using the SO ₄ solution, the resolution of the column 6 changes greatly. Therefore, the measurement using the pure water is performed within this time (within 2 hours), desirably. It was confirmed that by completing the process within 1.5 hours, it was possible to prevent a decrease in resolution.
Even if the measurement time has passed, some time is required, but the measurement can be performed again by performing the same regeneration operation of the column packed with the aqueous gel filtration as described above.

By repeating the same operation, intermittent measurement of the sample becomes possible. Utilizing such column characteristics, continuous measurement is also possible by combining a plurality of columns 6 and sequentially measuring them.

Next, in order to clarify the features of the present invention, an ozone reaction characteristic relating to water treatment of an organic substance and a feature of a detector used in high performance liquid chromatography will be described.

In recent years, ozone having a strong oxidizing power has been used for treating water contaminated with organic substances. Typical purposes of the ozone application equipment in the water treatment are oxidative decomposition of chromaticity components, odor components, COD components, etc. in the water to be treated, sterilization of general bacteria and coliforms, and the like.

When the detectors are classified according to the detection sensitivity,
Although the refractive index detector having a detection sensitivity of 10 ⁻⁷ g has a low sensitivity, it has an advantage that it can measure the entire dissolved substance including inorganic substances and organic substances. Next, an ultraviolet absorption detector having a detection sensitivity of 10 ⁻¹⁰ g responds only to an organic substance having an ultraviolet absorption, and therefore cannot show the entire dissolved organic substance.

On the other hand, a fluorescence detector having a detection sensitivity of 10 ⁻¹² g cannot measure the whole dissolved organic substances as in the case of ultraviolet absorption, but has a high sensitivity capable of selectively detecting humic substances, proteins and polycyclic aromatics. It is a detector of sensitivity, used for evaluating various water qualities such as raw water for tap water and various environmental waters, treated water and drinking water for each treatment step of water supply facilities, bottled water,
It is a detector suitable for grasping representative trace dissolved organic matter related to pollution.

In consideration of such ozone reaction characteristics and known characteristics of a detector used in high performance liquid chromatography, the present inventors performed various measurements, and as a result, the characteristics of the entire dissolved substance were determined by the chromatogram of the refractive index. And the chromatogram of fluorescence can be used to characterize typical trace dissolved organic matter related to contamination, which makes it easy to pattern treated water and evaluate treatment status. became. (Specific Example) Next, using the water quality analyzer shown in FIG. 1, an example of a chromatogram of the refractive index and the fluorescence when the treated water in each step of the water treatment is used as a sample is shown to evaluate the treatment state. The samples used were treated water and drinking water in each of the advanced water purification and sewage advanced treatment processes.

First, polyethylene glycols having different average molecular weights were developed as organic substances. In this case, an aqueous gel filtration packed column having the resolution shown in the calibration curve of FIG. 2 between the outflow time and the molecular weight fractionation characteristics was used as the aqueous gel filtration packed column 6. Using this column, changes in the chromatograms of refractive index and fluorescence were analyzed using treated water from each step of the advanced water purification treatment using a lake as a water source.
FIG. 3 shows the analysis results.

As shown in FIG. 3, the characteristics of the entire dissolved substance can be confirmed by the chromatogram of the refractive index. From the chromatogram of fluorescence, it can be seen from the chromatogram of fluorescence that the trace amount of dissolved organic matter mainly exists in raw water with a molecular weight of about 2,000, and that the dissolved organic matter of tens of thousands to 1,000 is slightly removed by coagulation and sand filtration. This indicates that the flocculant is effective for organic substances in the polymer region. The decrease in the peak of the chromatogram indicates that the dissolved organic matter was oxidized and de-molecularized by the ozone treatment and caused a qualitative change.

FIGS. 4 and 5 show the chromatograms of the refractive index and the fluorescence when drinking water from a water tap (water tap) is used as a sample. The sample is tap water obtained in a normal treatment step using river surface water as a water source.
FIG. 5 shows a chromatogram of tap water in Town B (No. 45).
, National Water Research Conference, Evaluation of Drinking Water by High Performance Liquid Chromatography 1994.5).

Comparing the total amount of dissolved substances, it can be seen that town A is larger than town B. In addition, the peaks of the towns A and B both rise sharply, indicating that a relatively single inorganic substance exists. In particular, the water quality of the water source in town B is good and there are few dissolved substances. The amount of dissolved organic matter is relatively small in both towns A and B.
In town B tap water, the presence of dissolved organic matter that shows fluorescence on the high molecular weight side is recognized.

As described above, since there is a chromatogram specific to each tap water depending on the water source of the drinking water and the treatment status, the evaluation can be performed in a shorter time and more easily than the chromatogram at the time of the optimal treatment.

Further, FIGS. 6 to 8 show various chromatograms of a treatment facility in which advanced treatment is performed for the purpose of effectively utilizing water resources of sewage treatment water and water for scenic and hydrophilic use is secured. FIG.
Uses sewage secondary treatment water as raw water, removes turbidity by coagulated sand filtration,
It is a chromatogram of an A treatment plant which supplies lands for scenic water after decomposing and sterilizing chromaticity and odor components with ozone. FIG. 7 shows that the coagulated sand filtered water of the secondary sewage treatment is used as raw water, chromaticity and odor components are decomposed and sterilized with ozone, trace amounts of dissolved organic substances decomposed with bioactive carbon are removed, and water for hydrophilicity is supplied after simple chlorination. It is a chromatogram of a processing plant. Figure 8 is a raw sewage secondary treatment water, NH 4 _-N removal and turbid component removed biofilm filtration, ozone chromaticity-odor components decompose, sterilized, C treatment plants chromatogram supplying hydrophilic water It is.

In the chromatogram of the refractive index indicating the entire dissolved substance, the characteristics of the sample water quality can be patterned based on the height, number, and position (outflow time) of the peaks. In any case, after the ozone treatment, the peak of the fluorescence chromatogram decreases, and a favorable treatment effect can be confirmed.

At the tap water source, countermeasures against trace contamination by chemical substances such as organic pesticides and trihalomethane, which is a by-product of the reaction between chlorine and trace dissolved organic substances such as humic substances, have become serious, and their behavior in the water purification process has become serious. Is essential. However, the usual water purification process is generally a process of physically and chemically removing turbid components such as water intake → sedimentation → pre-chlorine → coagulation sedimentation → medium chlorine → sand filtration → post-chlorine. Is hardly removed by the normal processing. Thus, harmful by-products due to chlorination pose a problem. On the other hand, in facilities with advanced treatment, for example, water intake → sedimentation → coagulation sedimentation → sand filtration → ozone → biological activated carbon →
As in the case of post-chlorination, trace amounts of dissolved organic matter are largely removed before chlorination, so the amount of harmful by-products and trihalomethane generated by chlorination is small.

As an item indicating the extent to which trihalomethane is generated, such as when chlorine is added in the final step of water purification, there is trihalomethane generation ability. The present inventors have determined that the fluorescence intensity obtained with the water quality analyzer according to the present invention and the trihalomethane generation The results confirm that the production ability shows a good positive correlation. In addition, measurement of a low-boiling organic halogen compound represented by trihalomethane requires complicated operations such as a head space method and a solvent extraction method among gas chromatography methods.
From this, it is considered that trihalomethane generation ability can be predicted by the fluorescence intensity obtained by the water quality analyzer according to the present invention, and a complicated water quality analysis operation can be omitted.

As described above, according to this embodiment, the characteristics of the dissolved organic substance and the characteristics of the whole dissolved substance can be simultaneously detected by using pure water as the developing solvent. When the capacity of the column 6 packed with aqueous gel filtration is reduced, the column can be regenerated by periodically flowing a Na ₂ SO ₄ solution into the column 6.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 9, the first storage tank 1A and the second storage tank 2 are arranged in parallel, and the liquid feed pumps 3A and 3A are respectively provided.
B sends the liquid to the sample injector 4 side. The liquid feed pumps 3A and 3B are connected to an inlet valve 3E on the upstream side of the sample injector 4.

The second storage tank 2 is connected to a pipeline from the first storage tank 1A to the liquid feed pump 3A via a switching valve 3D, and further connected to a flow control device 3C to the liquid feed pump 3A. I have.

An outlet valve 6A is connected to the downstream side of the aqueous gel filtration column 6, and the outlet valve 6A sends the liquid in the system to either the differential refractometer 7 or the outside of the system. I have.

In FIG. 9, the first pump is provided by the liquid feed pump 3A.
Pure water 2 as a developing solvent in the storage tank 1A is sent to the sample injector 4 and the column 6 side and measured for 2 hours.

Hereinafter, the automatic reproduction operation will be described in detail. First, two hours after the start of the measurement, a message indicating that measurement is not possible is displayed, and the switching valve 3D is switched from the pure water side to the Na ₂ SO ₄ side, and at the same time, the inlet valve 3E and the outlet valve 6A are switched to the regeneration side.

Next, Na ₂ SO _{4 is} supplied at a flow rate of 0.5 ml / min by a liquid sending pump 3 B having a flow rate adjusting device 3 C.
Is flowed for 4 hours, then the switching valve 3D is switched to the pure water side, pure water is flowed at a flow rate of 0.5 ml / min through the sample injector 4 and the column 6 for 3 hours, and further at a flow rate of 1.0 ml / min. Pure water is allowed to flow for one hour, and regeneration of the column 6 is completed, indicating that measurement is possible. Note that a display device and a control device for the measurable time, the reproduction end time, and the like are separately provided. As a result, the aqueous gel filtration packed column 6
Can be used under optimal conditions.

The time required for regeneration is 8 hours and the measurable time is 2 hours, so that if the packed columns 6 are 5 sets, continuous measurement can be performed for 24 hours.

[0048]

As described above, according to the present invention, the characteristics of the dissolved organic matter and the entire dissolved substance can be simultaneously detected, and the operation management of the water treatment facility can be efficiently performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first embodiment of a water quality analyzer according to the present invention.

FIG. 2 is a calibration curve showing the relationship between molecular weight and outflow time when polyethylene glycols having different average molecular weights are developed.

FIG. 3 is a view showing various chromatograms of advanced water purification treatment.

FIG. 4 shows a chromatogram of tap water.

FIG. 5 shows a chromatogram of tap water.

FIG. 6 is a view showing various chromatograms of sewage altitude treatment.

FIG. 7 is a view showing various chromatograms of sewage altitude treatment.

FIG. 8 is a view showing various chromatograms of the advanced sewage treatment.

FIG. 9 is a schematic view showing a second embodiment of the water quality analyzer according to the present invention.

FIG. 10 is a schematic diagram showing a conventional water quality analyzer.

[Explanation of symbols]

 1A 1st storage tank 2 2nd storage tank 3,3A, 3B Liquid feed pump 3C Flow control device 3D, 4B switching valve 3E Inlet valve 4 Sample injector 4A Sample inlet 4C Sample loop container 5 Syringe 6 Silica gel packed column 6A Outlet Valve 7 Differential refractometer 8 Fluorometer 9 Recorder

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G01N 33/18 101 G01N 33/18 101 106 106Z (72) Inventor Nobuyoshi Kaiga 1-1-1, Shibaura, Minato-ku, Tokyo In the head office of Toshiba Corporation (56) References JP-A-7-128323 (JP, A) JP-A-7-63725 (JP, A) JP-A-1-143953 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01N 30/88 G01N 30/26 G01N 30/78 G01N 33/18

Claims (2)

(57) [Claims] 1. An aqueous gel filtration packed column for separating substances in order of molecular weight, a developing solvent supply device for transferring a developing solvent to the aqueous gel filtration packed column, and an aqueous gel filtration packing from the developing solvent supply device. A sample injection device for injecting a sample into a developing solvent transferred to the column side, using pure water as the developing solvent, and a detector for dissolved organic substances and a dissolved organic compound downstream of the aqueous gel filtration packed column. A water quality analyzer, wherein a detector for all substances is arranged in series. 2. A regenerating solution supply device for supplying a regenerating solution to the aqueous gel filtration packed column is provided in parallel with the developing solvent supply device on the upstream side of the aqueous gel filtration packed column. Water quality analyzer.