JPH02122894A - Method and equipment for clarifying liquid utilizing foamed plastic particle - Google Patents

Abstract

PURPOSE:To extremely efficiently remove dissoluble contaminant in sewage by utilizing the foamed plastic beads having 0.1-50mm average particle diameter or the particles of either pulverized material or cut material of a soft plastic foamed body as the particles in the case of passing sewage through a granular aggregate to clarify sewage. CONSTITUTION:The shape of the particle in a granular aggregate is preferably regulated to an indefinite type in order to obtain excellent clarification efficiency. As the respective particles, foamed plastic beads or the particles of either pulverized material or cut material of a soft plastic foamed body must be utilized. This granular aggregate can be made a filter zone for insoluble substance and also fulfills a role as the carrier of clarification microorganisms for aerobically or anaerobically decomposing organic substance. Organic contaminant is anaerobically decomposed by microorganisms and furthermore aerobically decomposed and therefore it is preferable that aeration is sometimes or always performed toward the granular aggregate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for removing soluble pollutants in wastewater by means of a luminescent plastic particle aggregate.

[Prior Art] Liquid purification methods using particle aggregates as filter media and purifying microorganism carriers are known, for example, from Japanese Patent Publication No. 56-6324 and Japanese Patent Publication No. 63 mm1 (No. 5). Sewage purification using aggregates of stone particles is described in "Water and Wastewater JI 987 Vol. 1.29. No.l (Industrial Water Investigation Committee). Sewage purification using anthracite is also known. .

[Problem to be solved by the invention a] Using an aggregate of particles as a filter medium makes it easy to backwash or purify the filter medium when the filter becomes clogged with contaminants, and the surface area of the filter medium is reduced. It has the advantage that it can be made very large and can also serve as a carrier for purifying microorganisms. However, there are various types of pollutants, and in particular, removing soluble pollutants through biological treatment and effectively lowering the C (〕0.800) of wastewater is important. It is difficult and not easy to select the above-mentioned porous artificial stone particles and anthracite particles.Since they are inorganic porous, they are very brittle and easily destroyed by backwashing etc. and the particle size changes easily, so they do not last long. It is not possible to manufacture the material with the desired porosity and specific gravity.

[Means for Solving the Problem] The present inventor has proposed that when wastewater is purified by passing through a particle aggregate, foamed plastic beads having a beef particle size of 0.1 to 50+wm, crushed soft plastic foam, or He discovered that soluble pollutants in wastewater can be removed extremely efficiently by using cut particles, and that the particles are not brittle, can withstand repeated backwashing, and last a very long time, leading to the completion of the present invention. reached.

In the present invention, soluble organic pollutants refer to organic pollutants that are literally dissolved in water and cannot be removed by simple filtration. Soluble organic pollutants, like insoluble substances, are substances that cause BOD and COD, and are decomposed aerobically and anaerobically by purifying microorganisms on the surface of particle aggregates, and treated water after being purified. ROD and C0II are significantly reduced.

The particle aggregate of the present invention can serve as a filtration zone for undissolved matter, but it also serves as a carrier for purifying microorganisms that decompose organic matter aerobically and anaerobically. A particle aggregate is simply a collection of disparate particles,
They do not need to be particularly bonded or entangled. However, the particles may be fixed to some extent as long as they can be broken apart by applying an appropriate force. Alternatively, it may be a particle aggregate that is floating and movable with respect to one another in waste water.

The average particle size of the particles is from 0.1 to 50 m-, and particles with a larger particle size than 50-metal steel cannot achieve good purification efficiency. Also, 0. Particles with a particle size of less than lsv tend to cause clogging in general wastewater, making it necessary to increase the size of equipment due to the increase in backwash frequency and amount of backwash water. This increases running costs and makes it impractical.

The shape of the particles in the particle aggregate is preferably amorphous in order to obtain good purification efficiency. When the particle shape is a regular shape such as a sphere, water channels are created in the particle aggregate, from which sewage flows out at high speed, and purification efficiency tends to be poor. Further, for the same reason, it is preferable that the particle sizes in the particle aggregate are irregular.

Each twig of the particle assembly must be a foamed heath (e.g. expanded polystyrene heath) or a crushed or cut piece of soft plastic foam. If hard plastic particles that do not foam are used, they will not be compatible with the microorganisms on the surface. However, in order to eliminate clogging and perform backwashing effectively, it must be soft enough to maintain its shape. The foamed plastic may be closed-celled or open-celled, but it must be foamed beads or crushed or cut foam that has many irregularities on its surface, increasing the contact surface between microorganisms and sewage. Must not be. Particularly preferred are particles produced by randomly crushing the plastic bodies of the 5 insects standing air bubbles.

The porosity of the entire particle aggregate is up to about 98% for expanded polystyrene heat, and for other types it is usually 50-9.
Although 0'g is preferable, the lower the void ratio, the higher the particle cost, and when the void space exceeds $9 oz, the higher the void ratio is, the worse the l-retention efficiency by southern organisms becomes. Examples of methods for passing wastewater through particle aggregates include the following methods.

■Simply pour dirty water over the single particle aggregate.

2.1 Provide a zone of particle agglomeration in the flow path of the wastewater or in the retention vessel in which the wastewater moves, flowing quietly in an ascending, descending or horizontal direction.

Examples of methods for providing the zone of particle aggregates in step 2 are as follows.

B. Close one side of the band or the image area with a wire mesh, etc. to prevent particles from moving.

Make the specific gravity of the particles lighter than that of sewage, float them under a wire mesh, etc. in an ascending or descending sewage flow path, and provide contaminant removal ports above and below separately from the flow path, or use a sewage treatment tank. The particle aggregate is floated on the surface of the sewage water, and the sewage is poured onto it.

Since organic contaminants are degraded anaerobically as well as aerobically by microorganisms, it is preferable to occasionally or constantly 11'jc to the particle mass.

The present invention will be explained in more detail with reference to Examples.

Example 1 Over the entire cross section of a septic tank, which has separate pollutant discharge ports at the top and bottom, into which wastewater from a paper mill flows in and purification liquid flows out, polypropylene Q>1 particles of irregular size and various average particle diameters were collected. An aggregate zone was provided. That is, paper mill wastewater (28.5°C pH 6°3) was treated with a 0,4+ particle aggregate layer of 3 mm (floating was prevented by a deterrent from above).
A two-stage purification was carried out using a septic tank with a diameter of 5.3 m and a height of 5.3 m, and a decrease in CO[l was observed. The results are shown below.

1: (B11 (1 load fiJ/+l+3/day) 0.1
It was also possible to use a particle size of -, and the removal rate was even better, but there was some clogging. From the table above and the above description, the particle size is 0.
The smaller the particles, the better the removal rate of C00 in the range of 1 to 50 mm, but in practice, particles with a diameter of 3 mm or less cause severe clogging, which increases the frequency of backwashing. When the diameter was 3 mm or less, the CI)D removal rate did not change in the case of biological treatment, but the above 1511
The amount of backwash water was increased by 5 to 10 times compared to that of 1111. Furthermore, if the sludge is less than 3 mm, the sludge concentration in the backwashed water is low and floc formation is poor, requiring precipitation treatment by chemical injection, but with the particles of the present invention, it is possible to reduce the turbidity to 3ffIg or less with a single sedimentation treatment without chemical injection. Met. This means that when the particle size is 3M or less, the amount of backwash water is large, making it necessary to increase the size of the equipment.

Example 2 Using Boria a, Ren foam particles and non-foam particles,
Domestic 9I wastewater (artificial wastewater was added to the ratio of 1 part human waste to 2 parts kitchen waste to 8 parts [)] 253a+g/l (16℃, p
H7, 2).

), the first stage is a 3m high particle aggregate layer (particle diameter 15m)
0,4 Enoki fl x 4m height implementation 1+Ii with
A septic tank similar to 1, the second stage is a particle aggregate I with a height of 0.5+++! 2 of a 0.75-diameter × 1° 5-meter high septic tank having a zone of J (particle size 2n+n+) in the wastewater flow path.
Purification was carried out with constant aeration using a stage, and the decrease in 8S0 and C00 was examined.

Example 3 Papermaking Water Recycling Polypropylene foam particles were used to purify papermaking water (ρ) 15.5) for water recycling. Eight particles with a diameter of 15 mm were placed at a height of 2II in the vertical direction. Septic tank (Is diameter x4+
m height, constant aeration), and a vertical septic tank (1 diameter x 1.5 m height,
When flowing at a flow rate of 2.5 m/h using filtration only),
Even after more than 10 days, there was no slime adhesion to the pipes, and the first
273 of the scum is removed in the second stage, and 17 of the scum is removed in the second stage.
3 was removed, and there was less clogging of the septic tank.

The reduction of various pollutants is shown in the table.

Example 4 River purification model Paper manufacturing wastewater (25
°C) in the flow path with polypropylene foam particle aggregate layer zone 1
The treatment was carried out using a vertical septic tank (0.4 m diameter x 5.3 ai height) with j+ (3 m height, particle tM 15 am). Since the BOD is low load, change the flow velocity and B
The rate of decrease in O[l was observed.

As mentioned above, the present invention provides a reduction in l(l)D (5B/l) at high flow rates (5-low/hr), short-time contact (20-30 minutes).
degree) can be achieved.

Example 5 Two-stage simple filtration a (kitchen wastewater treatment) Because the wastewater is contaminated with a lot of cooking oil, it is impossible to recover the oil after one breath, so 100 filtration piglets of average grain tlloia+ were added to the first stage.
〇-Steel (?A speed 8.8 m/hr), average grain size 21 in the second stage
Simple filtration was performed without aeration using a 800au+ filter bed (flow rate: 4.2 m/hour) to utilize the purifying power of microorganisms that naturally occur during water flow. The reduction in oil content, cloudy solids, and COD is shown below.

Oil content - g/l Fl solids - g/1 31.8 211.8 3.7 10.2 88.3! 95. H Effects of changes in flow rate (raw water treatment at Inhatonuma) Filter layer 1 of foamed polypropylene particle aggregates with a particle size of 15 cm
000m Cod water channel raw water is flowed downward at various flow speeds 0.5 to 7
I ran it at m1 o'clock. No sedimentation accelerator was injected.

COD-g/+ 176.9 27.6 83.8X Sewage treatment water removal rate Example 6 Raw water IE125 8O-1oo 18-25
30-50 60-900.5 0.5 [Effects of the present invention] The method and apparatus of the present invention enable efficient removal of soluble organic pollutants, and the particles used can be easily converted to the target release capsule. It can be used for a long time without breaking down.

Claims (1)

[Scope of Claims] 1. In a particle aggregate in which pollutant purifying active bacteria are artificially present in sewage or where pollutant purifying active bacteria are naturally present,
In the method of purification by passing with or without aeration, the particles are made of plastic formed into a foam piece, or made by crushing or cutting a plastic foam, and having minute irregularities on the surface. A method for removing soluble organic pollutants in wastewater, characterized in that the average particle size of particles of various sizes is 0.1 to 50 mm. 2. In a method for purifying wastewater by passing it through a multi-stage particle aggregate in which pollution-purifying active bacteria are artificially present or pollution-purifying active bacteria are naturally present, at least one of the above steps. The step is aeration, and the particles at that stage are made by forming plastic into foam beads, or by crushing or cutting plastic foam, and have a single particle size or various sizes with minute irregularities on the surface. The particles have an average particle size of 0.1 to 50 mm, and the other stages are not aerated and the particles at that stage form plastic into foam beads, or crush or cut plastic foam. of insoluble and soluble pollutants in sewage, characterized by particles having a single particle size or particles of various sizes with an average particle size of 3 mm or less and having minute irregularities on the surface. Removal method. 3. The method according to any one of claims 1 to 2, wherein the particle aggregate zone contains in advance a nutrient source for pollution-purifying active bacteria. 4. In a purification device having a particle aggregation zone in which pollution-purifying active bacteria are artificially present or where pollution-purifying active bacteria naturally exist over the entire cross section of the sewage flow path or sewage retention container, the particles Plastic is formed into foamed beads, or plastic foam is crushed or cut to have a single particle size with minute irregularities on the surface, or particles of various sizes with an average particle size of 0.1 to 50 mm. A device for removing soluble organic pollutants in wastewater, characterized in that the particles are