JPH0513693B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a phosphorus and COD remover for use in sewage treatment, pretreatment of raw water for water supply, and other water treatment in general. [Conventional technology] Sedimentation and drainage in water purification treatment of waterworks at temperatures above 160℃
A method for producing an adsorbent that is activated by heating at 200℃ and has a decolorizing ability that is not as good as activated carbon or activated clay, but is superior to zeolite, dusty clay, etc.
It is described in Publication No. 46895. [Problem to be solved by the invention] Conventionally, water purification treatment in waterworks involves adding an aluminum salt flocculant to relatively clean raw water to perform coagulation-sedimentation treatment of turbidity, etc., and removing flocs remaining from sand filters. is being captured. Therefore, the settled sludge produced by these treatments is
It contains a considerable amount of aluminum, and alumina is produced by sintering this. In addition, due to the recent increase in the injection rate of coagulants and the increase in the scale of treatment due to the contamination of water supply raw water, the amount of settled foam has become enormous, and its treatment has become a problem. As a result, effective methods of using resources are being considered. In this regard, as mentioned above, raw materials for adsorbents have been considered, but there is a problem in improving the performance of their use in abatement compared to the cost required for their production. [Means for Solving the Problems] This invention provides that coagulated sedimentation sludge contains a considerable amount of alumina through sintering treatment, and that even if there is variation in sludge components from water treatment plant to water treatment plant, the average adsorption The present invention provides a method for producing an adsorbent for water treatment from purified water sludge that maintains performance. In other words, coagulated and precipitated sludge is a product in which the flocculant turns into aluminum hydroxide and settles out together with suspended solids, but when this is subjected to red-hot drying treatment, it changes to α-type alumina at temperatures above 1100°C. However, the γ-type alumina in front of it has high adsorption performance and is difficult to dissolve in acids and alkalis, so it is used as an adsorbent, so sludge containing it becomes porous, especially during heat treatment. By using sludge granules as a carrier and forming a coating of highly pure γ-type alumina on it, we are able to correct variations in the component ratio of sludge discharged from water treatment plants and create a stable adsorbent for water treatment. It lies in manufacturing. In order to form an alumina coating on the carrier before sintering, it is advantageous to use a commercially available alumina sol. Examples of the properties of commercially available alumina sol are as follows. Al ₂ O ₃ 10~11% PH 4.0~6.0 Specific gravity (20℃) 1.09~1.14 Stabilizer CH ₃ COO Particle size Feather particle size 100mμ~10mμ Specific surface area ^m2 /g 300~500 Particle charge Positive crystal form Amorphous Color Tone Milky white Stability Semi-permanent permanent setting 0℃ Viscosity (25℃, CP) 50-3000 [Action] The above alumina sol is mixed with 100g of sludge
0g of Al ₂ O ₃ (100g as alumina sol)
impregnated with and fired in a furnace at a temperature between 400 and 1000℃. The water treatment adsorbent thus obtained becomes porous particles whose surfaces are coated with γ-Al ₂ O ₃ . The component ratio of sludge used as a carrier varies considerably depending on the water treatment plant or the time of sludge collection.
In other words, to give some examples,

〔Example〕

Distilled water 2 was added to 1 kg of dried sludge collected from the N water treatment plant and pulverized, and the mixture was granulated using a granulator to a particle size of 1.2 to 2.0 mm. Put 3Kg of this granulated sludge into an electric furnace for 1000
The mixture was calcined at ℃ for 30 minutes to obtain 850 g of granular adsorbent carrier. Add 500g of commercially available alumina sol to 500g of this granular carrier.
The sample was impregnated with g and dried in a dryer at 100°C for 5 hours. After drying, it was fired in an electric furnace at 600°C for 3 hours to obtain 570g of an adsorbent for water treatment. This is the particle size
Sample 1 was obtained by sieving to a size of 0.7 to 1.0 mm. In the same way, sludge was collected from Y water treatment plant, pulverized, 1 kg of dried sludge was added with 2 ml of distilled water, and the particle size was determined using a granulator.
It was granulated to a size of 1.2 to 2.0 mm. 3 kg of this granulated sludge was placed in an electric furnace and fired at 1000°C for 30 minutes to obtain 650 g of granular adsorbent carrier. 500 g of a commercially available alumina sol was impregnated into 500 g of this granular carrier, and the resultant was placed in a dryer at 100° C. and dried for 5 hours. After drying, it was fired in an electric furnace at 600°C for 3 hours to obtain 570g of an adsorbent for water treatment.
Sample 2 was obtained by sieving this to a particle size of 0.7 to 1.0 mm. The performance of the water treatment adsorbent of this invention was tested regarding phosphorus and organic matter (KMnO ₄ consumption) in water. As for the apparatus, a glass tube with an inner diameter of 1.8 cm was filled with water treatment adsorbent to a height of 30 cm to form a layer, and an overtest was conducted at a speed of 3 m/D. Before starting the filtration, the water treatment adsorbent was washed with pure water. Example 1 Three cylinders are arranged, A, B, and C. A and C are filled with sample 1, and B is filled with sample 2. The test water is raw water from the T river in Tokyo with a special phosphorus component added.
Three types were created: 1p.pm, 10p.pm, and 50p.pm.

[Table] As shown in the table above, there was no particular change in the PH value for each cylinder, but the KMnO ₄ consumption was 50%
Regarding phosphorus, a removal rate of over 95% was obtained. A noteworthy effect that appeared simultaneously in this test was the removal of iron ions and manganese ions. The test results in tube A were as follows: Raw water Treated water Fe 1ppm 0ppm Mn 1 0.05ppm, but this removal of manganese was different from that of ordinary manganese sand, and chlorine was not injected. This value is the value 20 minutes after the start of water flow. Example 2 In this case, a certain paper carton factory wastewater was tested for industrial wastewater treatment. To regenerate this water treatment adsorbent, its functionality can be restored by desorbing PO ₄ ^-3 with a few percent alkaline solution.

〔Effect of the invention〕

Since the present invention is carried out as described above, a pretreatment basin may be provided using only the present water treatment adsorbent to treat contaminated raw water. Furthermore, if it is placed on top of the sand layer of the slow-pass pond, a certain degree of treatment effect can be obtained for the sewage components. In addition, it is effective for removing phosphorus from treated sewage water, industrial wastewater, and small-scale sewage as well as reusing sludge.

Claims (1)

[Claims] 1. In the manufacturing method for water treatment adsorbents that heat-treat water treatment plant sludge, the dried and pulverized sludge is sintered at about 1000℃, impregnated with alumina sol, dried, and then sintered at a temperature of 400℃ or more and 1000℃ or less. A method for producing an inorganic adsorbent for water treatment, characterized by forming a γ-Al ₂ O ₃ film on the surface of a porous carrier.