KR20030003206A - Coagulation method of sewage and waste water by using magnetite powder - Google Patents

Abstract

PURPOSE: A coagulation system of sewage and wastewater using magnetite is provided, in which magnetized magnetite powder instead of coagulants such as alum is used to coagulate suspended solids contained in wastewater, so that the amount of sludge is greatly diminished and operating cost also is reduced by recycling the magnetized magnetite powder and by eliminating neutralizing process of the alum treated wastewater. CONSTITUTION: The coagulation system of sewage and wastewater using magnetite comprises a rapid mixing tank(1) into which raw wastewater and magnetite powder are fed; a slow mixing tank(3) into which polymer is fed in an amount of 2 to 3 mg/L with agitating for flocculation; a settling tank(5) in which coagulated suspended solids are settled down while supernatant water overflows over a weir into a treated water tank(8); a sludge pump(7) which transfers settled sludge to a sludge hopper(10) so that magnetite powder is collected on a magnetic roller(11); and a magnetite conveyor(12) which returns recovered magnetite powder to the rapid mixing tank for reuse.

Description

Coagulation method of sewage and waste water by using magnetite powder

In the present invention, suspended solids (SS; Suspended solids) contained in sewage and waste water are agglomerated using magnetized magnetite powder and precipitated in a sedimentation tank, and the magnetite powder is recovered in a recovery process. The present invention relates to a flocculation treatment method with low operating cost while minimizing sludge generated by reuse.

In general, the flocculation method of suspended solids contained in sewage and waste water is coagulated by injecting flocculants such as iron chloride, iron sulfate, alum and poly aluminum chloride (PAC) and polymer flocculent aid, and then separating and removing them from the settling tank. Since the process is common, most of the sludge generated is occupied by hydroxides of these flocculants, and the amount of generated sludge is high, resulting in high waste disposal costs and high operating costs since the neutralizer is consumed to neutralize these flocculants to produce hydroxides. There is a problem.

The present invention is to provide a method for coagulation removal of suspended solids contained in sewage and wastewater with low sludge generation amount and low operating cost in order to solve the above problems.

In order to achieve the above object, the present invention utilizes magnetite magnetite powder as a nucleus for flocculation to flocculate suspended solids contained in sewage and wastewater, and then precipitates and separates them in a sedimentation tank. Because it recovers and reuses it, it proposes a flocculation treatment method with low operating cost because it does not need neutralizer while minimizing sludge generation.

1 is a coagulation treatment process chart of wastewater using magnetite powder

[Explanation of symbols on the main parts of the drawings]

1: coagulation reaction tank 2: coagulation reaction tank stirrer

3: flocculation tank 4: flocculation tank stirrer

5: settling tank 6: settling tank (Rake)

6: Sludge Transfer Pump (Pump) 8: Treatment Tank

9: Treated water transfer pump 10: Sludge hopper (Hopper)

11: Magnet Roller 12: Recovered Magnetite Conveyor

When the magnetized magnetite used in the present invention comes into contact with water (fluid), magneto-hydro-dynamics (MHD) voltage is generated, and the magnetite surface exhibits a charge while the floating solid material in the water. Collected by electric attraction, it acts as a nucleus of agglomeration, and water passes through a magnetic field of magnetite magnetite, and as a result of waves of electrons, a group of water molecules is collected. As the microstructure becomes smaller, the surface tension decreases, the penetration force improves, solubility improves, deodorization efficiency improves, and cell membrane permeability of microorganisms improves in the later biological treatment process. It is effective in activating the metabolic activity of microorganisms.

Hereinafter, the contents of the present invention will be described in detail with reference to the drawings.

When the sewage and wastewater flow into the flocculation tank 1, a powder obtained by pulverizing magnetite magnetized with a magnetic flux density of 200 G (Gauss) or higher to about 40 to 60 µm is injected and stirred by the reaction tank stirrer (2). In this case, suspended solids are trapped on the surface of magnetized magnetite, which acts as agglutinating nucleus, causing coagulation. The sewage and wastewater in which suspended solids are aggregated is sent to the coagulation tank (3). While slowly stirring with a flocculation tank stirrer 4 while injecting about 3 mg / L, precipitates are easily formed in the precipitation tank 5 and then sent to the precipitation tank 5.

In the settling tank (5), the flocculated suspended solids are settled in the lower part of the settling tank, and the blue solid water from which the suspended solids are removed is overflowed to the weir (top) of the settling tank (5), and then treated. It is sent to the post-treatment process by the water feed pump (9), and the precipitated sludge is sent to the sludge hopper (Sludge Hopper: 10) of the magnetite recovery process by the sedimentation sludge transfer pump (7), and the magnetic magnetite powder is a rotating magnet installed on the upper part. Once attached to the roller 11, it is separated and recovered by a scraper and returned to the coagulation reaction tank 1 by a recovering magnetite conveying conveyor (Conveyor 12) for reuse, and the sludge from which the magnetite is removed is transferred to the sludge storage tank. Send to post-treatment process such as dehydration treatment.

Example 1

150 ~ 200㎥ / day of wastewater discharged from squid processing plant is injected with 800mg / ℓ of powder pulverized magnetite with magnetic flux density of 220G (Gauss) to 50㎛, and then 3mg / ℓ of polymer coagulant is injected. After stirring, the water of supernatant and 500mg / ℓ of Alum were stirred and neutralized, followed by neutralization treatment with caustic soda (NaOH) to 7, followed by 3mg / ℓ of polymer coagulant to precipitate. The water quality of the superior water is shown in Table 1.

As described above, in the present invention, as a result of agglomeration of the suspended solids contained in the sewage and waste water by magnetizing magnetite powder, the coagulant is neutralized with a neutralizing agent after injecting a flocculant such as alum and then flocculated and precipitated. As the treatment efficiency is almost equal, the magnetic magnetite is recovered and reused, and the sludge generation amount is very small and the neutralizing agent is not required. Therefore, the operation cost is low, and it is expected to be widely used in the condensation treatment of sewage and wastewater.

Claims (1)

In the flocculation sedimentation treatment of suspended solids (SS; Suspended Solid) contained in sewage and waste water, when the sewage and waste water flows into the flocculation reaction tank (1), magnetic agglomerated magnetite powder is injected and stirred to flocculate suspended solids. Floating into the flocculation tank (3) to form flocs (Floc) while slowly stirring the flocculation tank stirrer (4) while injecting about 2-3 mg / L of the polymer flocculant into the flocculation aid (3). Solids are settled in the lower part of the settling tank, and the blue water from which the suspended solids are removed is overflowed through the weir in the upper part of the settling tank 5 and sent to the treated water tank 8 by the treated water transfer pump 9. After the sludge hopper (Sludge Hopper: 10) of the magnetite light recovery process by the sedimentation sludge transfer pump (7), the magnetic magnetite powder is attached to the rotating magnet roller (Roller 11) By scraper In the coagulation treatment process of sewage and wastewater, the magnetite recovered after the separation is returned to the coagulation reaction tank 1 by a recovery magnetite transfer conveyor (Conveyor) 12 and reused, and the sludge from which the magnetite is removed is sent to a sludge storage tank for treatment. A method of flocculation of solid suspended solids (SS) using magnetized magnetite powder while minimizing sludge generation.