JPH0729101B2 - Inorganic wastewater coagulation treatment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a coagulation treatment apparatus for inorganic waste water containing heavy metals. More specifically, the present invention relates to a coagulation treatment apparatus for inorganic waste water, which is controlled so as to have an optimum coagulant addition amount according to the flow rate of raw water and the concentration of heavy metal ions.

[Prior Art] Conventionally, when coagulating sedimentation treatment of inorganic wastewater containing heavy metals, when adding inorganic coagulants such as aluminum chloride, polyaluminum chloride and aluminum sulfate and polymer coagulants, The amount added was constant. In this case, if there is a change in raw water conditions such as the raw water flow rate and the concentration of heavy metal ions in the raw water, the coagulant addition amount becomes excessive and is wasted unless the coagulant addition amount is manually adjusted, Alternatively, there has been a phenomenon in which the amount of coagulant added is insufficient and the quality of treated water deteriorates.

On the other hand, an ion concentration sensor that detects the concentration of heavy metal ions and a means for detecting the flow rate of raw water are installed, and these concentrations and flow rates are input to a microcomputer, etc., and automatic control is performed so as to obtain the optimum coagulant addition amount. However, the sensor and the microcomputer are expensive, and the ion concentration sensor cannot be accurately detected unless it is frequently inspected and washed and calibrated.

[Problems to be Solved by the Invention] As described above, in the conventional inorganic wastewater coagulation treatment apparatus, if the raw water conditions change, the coagulant addition is wasteful, or the treated water quality becomes unstable, or There is a problem that the configuration cost is extremely high and the maintenance management is complicated.

[Means for Solving Problems] The apparatus for coagulating inorganic wastewater according to the present invention comprises a means for adding a coagulant to inorganic wastewater (raw water), a means for detecting the flow rate of raw water, and a pH adjuster for raw water. PH adjusting means to bring the pH to a predetermined range, means for detecting the SS concentration in the pH adjusted raw water, and
A means for controlling the coagulant adding means is provided so as to add a predetermined amount of the coagulant. This control means is based on the relationship between preset raw water flow rate, SS concentration and coagulant addition amount, and SS
The amount of the coagulant to be added is controlled based on the SS concentration detected by the concentration detecting means.

[Operation] In the coagulation treatment apparatus of the present invention, by adding a pH adjuster to the inorganic waste water to bring it to a predetermined pH, the heavy metal ions contained in the raw water are, for example, iron hydroxide, zinc hydroxide, etc. It becomes hydroxide and becomes SS (suspended substance). This SS concentration has a correlation with the amount of heavy metal ions in raw water.
Therefore, the SS concentration and the detected value of the raw water flow rate are input to a control means such as a sequencer to calculate the coagulant addition amount, and the coagulant is added at the calculated ratio.

Therefore, in the device of the present invention, an appropriate amount of the coagulant is added to the raw water according to the heavy metal concentration in the raw water and the flow rate of the raw water.

Embodiments Embodiments will be described below with reference to the drawings.

FIG. 1 is a system diagram showing an apparatus according to an embodiment of the present invention. Reference numeral 1 is a raw water measuring tank equipped with a flow meter 1a and constitutes a raw water flow rate detecting means. On the downstream side of the raw water measuring tank, a pH adjusting tank 2 provided with a turbidity meter 2a and a pH meter 2b as SS concentration detecting means, a flocculation tank 3 and a precipitation tank 4 are sequentially arranged. Reference numeral 11 is a sequencer for performing arithmetic processing, to which the detection values of the flow meter 1a and the turbidity meter 2a are input. Reference numeral 12 is a storage tank for the pH adjuster, and the pH is adjusted by the pump 13.
The adjusting agent can be supplied to the pH adjusting tank 2. Reference numeral 14 is a control device for the pump 13, to which the detection value of the pH meter 2b is input so that the pH in the pH adjusting tank 2 falls within a predetermined range.
The supply of pH adjuster is controlled. These pH adjuster storage tanks
The pH adjusting means is constituted by the pump 12, the pump 13 and the control device 14. Reference numeral 15 is a storage tank for the inorganic coagulant, which is a pump.
This inorganic coagulant can be supplied to the pH adjusting tank by 16.

Reference numeral 17 is an inverter to which a signal from the sequencer 11 is input, and outputs a control signal to the pump 16. Reference numeral 18 is a dissolution tank for the polymer coagulant, and the polymer coagulant can be supplied to the coagulation tank 3 by the pump 19. The pump 19 is controlled by the sequencer 11 via the inverter 20. Storage tank 15 for these flocculants, dissolution tank 18, pump
The means for adding the flocculant is constituted by 16 and 19. Further, the sequencer 11 and the inverters 17 and 20 constitute a control means of the coagulant addition means.

Next, the operation of the apparatus of the above embodiment will be described. The inorganic waste water is introduced into the raw water measuring tank 1, and its flow rate is detected by the flow meter 1a and input to the sequencer 11. The raw water is then introduced into the pH adjusting tank 2 and added with a pH adjusting agent and an inorganic coagulant. The pH adjusting agent is detected by the pH meter 2b as described above.
The addition is made so that the pH is within a predetermined range. Heavy metal ions contained in the raw water due to pH adjustment
It becomes SS. This SS concentration is detected by the turbidimeter 2a, and the detection signal is input to the sequencer 11. The water to be treated from the pH adjusting tank 2 is then introduced into the flocculation tank 3, a high molecular flocculant is added to grow fine SS into large flocs, and then the flocculation tank 4 is introduced to perform sedimentation separation of the flocs. . The sedimented flocs are discharged as sludge and sent to the sludge treatment system. Also, the supernatant is sent as treated water to the discharge process and the higher-order treatment process.

Then, the sequencer 11 calculates the addition amount of the coagulant based on the detected raw water flow rate and SS concentration. The coagulant addition amount corresponding to the SS concentration and the raw water flow rate is input to the sequencer 11 in advance. As shown in FIG. 2, this addition amount is set so as to increase as the raw water flow rate increases and increase as the SS concentration increases. (A, B, and C in FIG. 2 have a relation of A>B> C.) The operation signals from the sequencer 11 are converted into operation signals of the pumps 16 and 19 by the inverters 17 and 20 and output,
Pumps 16 and 19 respectively supply a predetermined amount of inorganic coagulant and polymer coagulant to the pH adjusting tank 2 and the coagulating tank 3.

In the coagulation treatment apparatus configured in this way, since the amount of the coagulant added is controlled in accordance with the raw water flow rate and the heavy metal ion concentration in the raw water, even if there are fluctuations in these raw water flow rate and heavy metal ion concentration, The optimum amount of flocculant will be added. Although the sludge is separated by the settling tank 4 in the above embodiment, a flotation separation device may be used in addition to the sedimentation separation device.

[Effect] As described above, in the inorganic wastewater coagulation treatment apparatus of the present invention, the coagulant addition amount is controlled in accordance with the raw water flow rate and the heavy metal ion concentration in the raw water, so that the coagulant addition amount is appropriate. And the cost of chemicals can be reduced. Further, since the proper amount of coagulant is always added, the quality of treated water becomes extremely stable. Moreover, since the device of the present invention can be configured by a device that is relatively inexpensive and easy to maintain and manage, it is excellent in practicality.

[Brief description of drawings]

FIG. 1 is a system diagram showing an apparatus according to an embodiment of the present invention, and FIG. 2 is a graph showing the amount of coagulant added. 1 ... Raw water measuring tank, 2 ... pH adjusting tank, 3 ... Coagulation tank, 4 ... Precipitation tank, 11 ... Sequencer, 15 ... Inorganic coagulant storage tank, 18 ... Polymer coagulant dissolving tank.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yozo Sasaki 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (no address) Kawashima Steel Co., Ltd. Mizushima Works (72) Inventor Kajii 3-chome Nishishinjuku, Shinjuku-ku, Tokyo 4-7 Kurita Industry Co., Ltd. (72) Inventor Satoru Nagai 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo Tokyo Kurita Industry Co., Ltd.

Claims (1)

[Claims] Claim: What is claimed is: 1. An apparatus for performing coagulation treatment by adding a coagulant from an aggregating agent adding means to an inorganic wastewater containing heavy metals, a means for detecting the flow rate of raw water; PH adjusting means; means for detecting SS concentration in pH adjusted raw water; and relationship between preset raw water flow rate, SS concentration and coagulant addition amount, and SS concentration detected by the above means And a means for controlling the coagulant adding means so as to add a predetermined amount of the coagulant.