JPS59186689A - Process and device for eliminating turbidity of turbid water by flocculation - Google Patents

Abstract

PURPOSE:To eliminate turbidity from turbid water stably by allowing turbid water incorporated with a flucculating agent to flow downward through a floc forming tank provided with many arranged perforated plates to straighten the flow and to settle generated floc, then allowing the scum to float up by pressurization in a floatation tank. CONSTITUTION:Turbid water is supplied to a mixing tank 1 and stirred immediately and quickly together with a chemical such as flocculating agent (a) injected into the tank 1 using a quick stirring device 2. The stirred turbid water is supplied to a floc forming tank 4 through an orifice at the bottom of a partition wall 3. Many perforated plates 5 are provided vertically with an optional distance in the floc forming tank 4 in the direction for inhibiting downward flow of the turbid water. When the turbid water flows down through the group of the perforated plates, suspended matters in the turbid water are flocculated by the effect of the flocculating agent and flow downward through each hole of the perforated plates. When supernatant water in a flow straightening and settling tank 6 is supplied to the next floatation tank 8, suspended matters which are not settled in the settling tank 6 are floated by the effect of air bubbles released from pressurized water to form scum and are discharged out of the tank.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for the complete coagulation and turbidity removal of suspended water in water supplies, industrial waterways, sewers, civil engineering drainage, human waste treatment, industrial wastewater treatment, etc.

There are two kinds of suspended matter in turbid water: inorganic matter and organic matter (algae, etc.); inorganic matter has a high density and tends to settle, but organic matter has a small Sedimentary,
Rather, it has the property of being easy to float. In normal river water, inorganic turbidity makes up most of the water, while in lake water and nutrient-rich reservoir water, organic turbidity often makes up the majority. Even in river water, the turbidity may change seasonally due to periods of drought, heavy rainfall, etc.

That is, during dry periods, organic turbidity is mixed or almost everywhere, and when turbidity increases due to localized heavy rain, most of the turbidity is inorganic. A coagulation-sedimentation device is generally used as a coagulation and clarification device, but when organic turbidity is present, difficult-to-settlement flocs often flow out into the treated water, and the rapid filtration device is not used after the rapid filtration device. When installed, the outflow flocs cause the filtration device to become clogged more quickly. Further, the conventional coagulation-sedimentation apparatus requires about 4 hours of residence time, including chemical mixing and floc formation.

The present invention takes advantage of this to achieve the same level of water quality as conventional coagulation and sedimentation equipment, which can treat all of the turbid water in 6 to 1/2 times the time, and with low to high turbidity raw water. In addition, the aim is to stably remove turbidity regardless of whether the turbidity is organic or inorganic, by injecting a flocculant into the suspended water and stirring it rapidly. The arrayed floc formation tanks are allowed to flow down to form desired flocs, which are then rectified and settled to perform primary clarification, and the supernatant water is led to a flotation tank where the scum is floated and separated under pressure using nuclides. % to perform secondary clarification of turbidity.
The first invention characterized in that a perforated plate flock forming tank in which a large number of perforated plates are arranged are brought into instant contact with a mixing tank in which a coagulant is injected into turbid water and rapidly stirred, and two ports of nuclide Ic 7 are collected. A rectifying sedimentation tank is provided to perform primary turbidity removal by sedimentation, and a flotation tank is installed to guide the supernatant water of this rectification sedimentation tank, and reduced-pressure bubbles are provided in the flotation tank to help float the scum. This invention is similar to the second invention, which is characterized in that it includes a generator and a sludge scraping device that performs secondary turbidity removal by scraping and scraping floating scum.

The following description will be made based on the fully illustrated embodiments of the present invention. Sewage - Suspended water (raw water) such as industrial, industrial, and civil engineering wastewater is supplied to the mixing tank 1, and flocculants, etc., are injected into the tank. Rapidly stir the drug using rapid stirring device M2. Reference numeral 3 denotes a partition wall provided between this mixing tank 1 and the next flocculation tank 4 that is brought into instant contact. It is made to supply from the opening to the 7-hole Jfi input 'fl'. This floc formation tank 4 has many porous holes @ 5 in the direction that prevent the flow of turbid water.
are vertically arranged at arbitrary intervals, and when flowing down the group of perforated plates 5, the suspended solids in the turbid water are turned into flocs by the action of the coagulant, and the flocs are grown while flowing through each pore of the perforated plate. The entire inside flows down. In this case, the size and shape of the perforated plate are arbitrary. For example, in order to facilitate flocculation, the pore diameter is made smaller on the upstream side near the mixing tank, and the pore diameter on the downstream side near the rectification settling tank is made larger, so that the pore diameters are gradually made larger from the upstream side of the perforated plate toward the downstream side. PL, in which perforated plates are arranged so as to have the same diameter, or perforated plates with the same hole diameter are arranged at unequal intervals on the upstream and downstream sides of the flocculation tank 9, all the perforation positions on each plate. The differently arranged PLs are arranged by aligning the perforation positions, but this arrangement method is only one example and is not limited to this. A rectifying sedimentation tank 6 is connected instantaneously to the downstream side of the flocculation tank 4 in which a large number of perforated plates are arranged, and the turbidity in the turbid water is supplied from the flocculation tank 4 to the rectification sedimentation tank 6 as floc makeup. Do what you want. A sludge v7 is installed at the bottom of this rectification sedimentation tank to discharge the flocculated suspended solids out of the tank, and when a certain amount of sedimentation is reached, it is discharged periodically or selectively. .

In this case, the bottom part is shaped like a ship's bottom or some other shape to facilitate the collection of settled flocculated suspended solids. In this rectified sedimentation tank, the main material is inorganic turbid matter that has high turbidity and settles easily. The flocculated turbidity is settled in this rectification sedimentation tank and primary clarification is carried out, but organic turbidity with low turbidity and turbidity that has not settled is transferred to the upper clear turbid water of the sedimentation tank. is supplied to the flotation separation tank 8. The supernatant turbid water supplied to this flotation tank 8 is separated by a partition plate provided on the upstream side of the flotation tank. supplied within. The lower part of the partition plate 9 is opened, and the nuclide is guided into the υ flotation separation tank through this opening. Pressurized water is supplied from the water storage tank 11. This pressurized water storage tank 11 is supplied with treated water from which floating turbidity Ji (scum) has been removed in a flotation separation tank or purified water pressurized with a gold pressurization pump 12, and is supplied with nuclide 1.
1 is supplied with pressurized air from a compressor 16, the air is dissolved under pressure, and when the air is blown out into the separation tank from the vacuum bubble device flit 10 through the pressurized water supply pipe 14, the air is dissolved in the pressurized water. Due to the reduced pressure, the air becomes bubbles and floats up inside the separation tank. At this time, organic turbid substances with low turbidity contained in the supernatant turbid water float to the surface and become scum on the upper liquid surface of the tank. This floating scum is scraped up by a sludge scraping device 15 installed at the top of the flotation separation tank and discharged to the outside of the tank.The treated water from which all turbidity has been separated is drained through a strainer 16. It is something.

EXAMPLE The treatment conditions of the above table were set to treat turbid water, and the flow was sequentially flowed from the mixing tank to the flocculation tank, the rectifying sedimentation tank, and the flotation separation tank to completely treat the turbid water. As a result, an effect similar to that of the method was obtained.

Therefore, when using the present invention, it is possible to treat turbid water in an extremely short time compared to conventional methods, and it is stable regardless of whether it is organic or inorganic, from low turbidity raw water to high turbidity raw water. It has the advantage of being able to remove turbidity.

[Brief explanation of drawings]

The drawing is a schematic view showing the apparatus for coagulating and removing turbidity of turbid water according to the present invention. 1...Mixing tank 2...@speed stirring device 6, 9...ViA wall 4...Block forming tank 5... Perforated plate 6... Rectifier settling tank 7...Sludge drainage pipe 8...Flotation separation tank 10... Decompression bubble generator 11... Pressurized water tank 12...Calorie pressure horn 1ro...compressor 14... Pressurized water supply pipe 15...Sludge scraping device 16...Strainer (1 other person

Claims (2)

[Claims] (1) After injecting the flocculant into the suspended water and stirring rapidly,
This is flowed down a floc formation tank with a large number of perforated plates arranged to form the desired flocs, and then rectified and settled to perform primary clarification.The supernatant water is then led to a flotation separation tank to scum with nuclides. A coagulation and clarification method for turbid water, characterized in that secondary clarification of turbidity is carried out by flotation separation under pressure. (2) A perforated plate flocculation tank in which a large number of perforated plates are arranged is placed adjacent to a mixing tank in which all of the coagulant is injected into turbid water and rapidly stirred, and rectification is performed to precipitate flocs on nuclides and perform primary clarification. A sedimentation tank is provided, and a flotation separation tank is installed to guide the supernatant water of this rectification sedimentation tank, and a decompression bubble generator to help float the scum to the upper separation tank and a floating scum removal tank are installed. A turbid water coagulation and clarification device that is equipped with a sludge scraping device that performs sludge removal using a scraper.