JPH01218689A - Sewage disposal facility - Google Patents

Abstract

PURPOSE: To alternately move the liquid surface in a vessel up and down at regular intervals and to allow organismic agglomerated lumps on a supporting device to alternately contact with a liquid and a gas, in the equipment.

CONSTITUTION: In this equipment, sewage 30 is introduced into a sedimentation chamber 19 through an inlet pipe 2 and allowed to flow in a downwardly orientated stream. Then, the inflow sewage 30 is mixed with sewage treated to some extent and organismic agglomerated lumps, in the zone 19 to form a liquid mixture 15 that is allowed to continuously flow through a screen 10 in the equipment. An inverted box 13 contg. a contact medium 14 of an organismic agglomerated lump supporting device is filled with the liquid mixture 15 whose liquid surface is at a level 17 in a vessel. When an air blower 11 is operated, air is transferred with a pressure to the inverted box 13 through a pipe 12 to remove the liquid mixture 15 from the inverted box 13. By this replacement of the liquid mixture 15 with air, the liquid surface in the vessel is raised to a level higher than the level 17 and further, the liquid mixture 15 is moved up through the other contact mediums 18 and 20 to backwardly pass the liquid mixture 15 through the screen 10 and to dilute the inflow sewage 30 with the liquid mixture 15. Thus, the purification effect of the equipment can be improved.

COPYRIGHT: (C)1989,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to sewage treatment facilities, particularly, but not exclusively, to sewage treatment facilities suitable for underground installation and used in locations where large sewage discharge facilities are not available. Relating to a sewage treatment facility suitable for either a single dwelling or a small group of dwellings, as an alternative to septic tanks or septic tanks.

Problems that the prior art and invention seek to solve: Sewage tanks are generally inadequate and their use is difficult because they generate odors, pollute the surroundings when they overflow, and are not used regularly, e.g. by road vehicles. This includes several problems and disadvantages, including the tendency to require pumping (based on Septic tanks are prone to contamination if they are installed in areas where soil conditions are not suitable. People living in areas where mains sewage discharge is not available need improved types of equipment for sewage treatment. The present invention provides a method that meets this need.

Means for Solving the Problems According to the invention, a sewage treatment facility includes a tank containing liquid sewage up to the liquid surface and gas above the liquid surface, an inlet for the sewage into the tank, and a treated sewage. an outlet from the tank, a bioclump support device in the tank, and the liquid surface in the tank is raised and lowered periodically to bring the bioclumps on the support device into alternating contact with the liquid and the gas. and a device for ensuring that.

Preferably, the first biological conglomerate support device is located in air when the liquid surface is at its normal height, while the second biological conglomerate support device is located in the air when the liquid surface is at its normal height. It is desirable to be located inside.

Preferably, the device for periodically raising and lowering the liquid surface in the tank comprises an inverted box, into which pressurized air can be supplied, and said second biological agglomerate support device is located within the inverted box. is desirable. By this method, the contaminants in the sewage to be treated are absorbed into the biomass supported on the support device and then oxidized to convert the contaminants into harmless substances and nutrients for the equipment.

This equipment is divided into a first settling chamber and a main and final settling chamber, and the corroded sludge that collects in the final settling chamber can be recirculated for further oxidation, thus reducing the total biological agglomeration during the low inflow of new pollutants. An endogenous respiration effect of 200 ml occurs, thus reducing the overall sludge production.

By mixing untreated and treated sewage in the tank and by circulating the final waste, nitrifying bacteria, which grow slowly, can control the concentration of oxygen-demanding carbonaceous bacteria, which is dominated by carbonaceous bacteria. The concentration is reduced to a level below the target concentration, thus providing favorable conditions.

The biological conglomerate support device preferably includes a plurality of upright or sloped contact plates having corrugated, textured or other protruding surfaces. This play 1~ is suitably arranged so that they form a number of upright or inclined channels by alternate reversals or other permutations of the plates ensuring that they touch only at high points. be positioned.

Said contact plates preferably have a mesh of sufficient strength to withstand the forces created by the movement of the liquid through the mesh structure and the weight of the biological conglomerate deposited on the plate when they are joined together. Preferably, the structure is made of polypropylene or any other suitable material that is vacuum formed or pressed into the desired shape so that the plate forms. An alternative bioagglomerate support device is made of random or regular polymeric fibers with a diameter of 1 to 1000μ, suitably supported in layers up to 20m thick, with an interfiber void ratio of 90% or more by volume. It can also be formed. This layer should be arranged approximately vertically to allow drainage.

The volume within the inverted box installed in the tank forms an anoxic zone during some operating periods of the installation and thus causes denitrification to take place. The sludge that rises to the surface due to the formation of nitrogen bubbles is broken down by the action of the rising and falling liquid level through the bioclump support device. This liquid movement also promotes agglomeration of the bioagglomerate particles, thus making them more easily separated from the liquid.

During periods of rising liquid level, some of the mixed treated sewage liquid containing a reduced amount of contaminants and agglomerated fine solids, after passing between the contact plates of the bioagglomerate support device, desirably , a container full of random or regular coarse fibers or strands with a diameter of 100μ to 1#, or a final fiber containing a random or regular surface with a void ratio of more than 90% by volume. It can flow into the settling chamber. Liquid flows upwardly through this reservoir and purified liquid flows to the outlet. If the liquid level in the main chamber of the tank falls (e.g. when the electric motor for the I!1 machine is switched off), the sludge collected together with the liquid in the final chamber is free from the risk of easy blockage. It returns to the body of the tank under the action of a siphon via a tube fitted with a check valve, preferably an inflated tube or other check device.

The sewage treatment facility according to the invention offers numerous advantages.

A. Although it is suitable for a single house, it can also be used to treat larger volumes of sewage from larger sources.

B. No electromechanical components are contained within the buried tank, which is an important advantage when the installation is located in an area where flooding may occur.

CO sewage is not stored for long periods of time before treatment, which reduces the possibility of septic sewage and therefore odor generation.

D. It can be easily installed in standby equipment to ensure continuity of operation.

E. Sewage is primarily treated by fixed film methods using static biological contact surfaces.

F. Treatment also occurs by oxidation of the floating biomass using oxygen that is decomposed as the liquid is drained from the biomass support surface.

G. The rise and fall of the liquid surface in the tank ensures a regular mixing of the incoming sewage with the treated sewage and biological agglomerates, thus ensuring that all stages of the treatment of sewage in the tank are Aerobic conditions exist.

In order that the operation of the invention may be more fully understood, a preferred type of sewage treatment installation according to the invention will now be described by way of example with reference to the accompanying drawings, in which: FIG.

Embodiments and operations FIG. 1 will be explained. The illustrated sewage treatment equipment may have any shape, for example circular or square in plan view.
(as shown) may be rectangular (contained in a tank 1. The tank 1 is just large enough to place enough soil on the tank cover 7 to grow grass or other small plants. As much as possible, so that the upper one Tsum 1a is below the horizon 5,
It is installed in the excavation recess 4. Cover 7 has its weight a h
(Supported on the rim 1a so as to be supported by the tank wall 6,
It has an opening 8 arranged to allow inspection and maintenance. The tank is held in the ground by a bottom flange 9 that resists flotation forces even if the soil surrounding the excavation recess becomes waterlogged. The flange 9 is shown as being further protected by concrete surrounding the tank, which may be desirable if no other suitable backfill material is available for this purpose.

The sewage water 3o enters the installation via the inlet pipe 2 and is deflected downwards by the baffle plate 26 into the first zone or settling chamber 19. The normal water level in the equipment is shown at 17, and this water level is used when the motorized retraction 11 is not activated. The incoming sewage 3o mixes with the partially treated sewage and biomass in the zone 19 to form a mixed liquor 15 which continues to flow through the screen 10 into the main room of the installation. The screen 10 has a minimum diameter within the zone 19 of 1
The screen, which retains zero or more solids, can be made of polymer strands laid out to form a mesh or mesh.

The mixed liquid 15 at water level 17 also fills the inverted box 13 containing the contact medium 14 of the bioclump support device. When the blower 11 is activated, air is forced along the tube 12 to displace the liquid 15 from the inverted box 13. This displacement raises the level of the surface of the liquid in the tank above the water level 17, causing the liquid 15 to rise through the contact medium 18, 20 in a further biomass support device and some liquid to pass through the screen 10. 15 is backwashed to dilute the influent sewage 30. The action of the rising liquid level breaks up any large suspended or scum solids, and the turbulence of the liquid prevents agglomeration of fine particles as it flows over the surface of the contact medium 18.20.
The blower 11 is operated with a timer-controlled switch that powers the blower motor at sufficiently frequent intervals so that the equipment operates well in oxidizing the contaminants and keeps the mixture oxidizable.

As the liquid mixture 15 passes over the surface of the contact medium 18.20.14, the biological agglomerates become deposited thereon, and the biological agglomerates adhere to the surface of the medium and absorb pollutants from the sewage. When the liquid level reaches the top of the partition wall 21, it overflows into the final settling chamber or zone 24 of the installation, where it is deflected downwards to the bottom of this zone, from where it passes through a final purification step 32 and drains the liquid. It rises to a surface 33 where a random network of polymeric fibers 34a combines with the structure of the support plate 34b to create a flocculating medium 34 where the final effluent water undergoes flocculation and purification before flowing to the outlet 3. can be caused. The feed motor 11a is switched off and the air contained in the inverted box 13 is sent back along the tube 12 due to the rising liquid level. Contact surface 14
During the period when it is exposed to air, the biological conglomerate on
The absorbed pollutants oxidize and the liquid held by the bioagglomerates and by the surface tension of the medium becomes saturated with oxygen.

When the liquid level recedes to the water level 17, the contact medium 18°2o becomes exposed to the air, and the biological agglomerates adhering to the medium surface and the surrounding water absorb oxygen from the air, which is absorbed by the biological agglomerates. Used to oxidize pollutants. The shedding of biological agglomerates from the surface of the media forms an "activated sludge" that uses dissolved oxygen in the water to oxidize the pollutants.

Facultative bacteria utilizing the chemically bound oxygen in the nitrates create anoxic conditions present in the medium 14 within the inverted box 13. This allows total nitrate nitrogen reduction to occur and oxidizes any carbonaceous contaminants present.

When the liquid level returns to the water level 17, the sludge and liquid in the final zone 24 are transferred to the action of the siphon via the siphon tube 22 terminating in the check valve 23 formed by a certain length of the inflation tube. It will be returned. The valve 23 is located in the area between the screen 10 and the inversion box 13.

This siphoning process involves the removal of excess sludge from the final zone 24, the mixing of the sludge and treated effluent with the incoming sewage as well as the biological agglomerates, the dilution of the sewage and the chemical removal from nitrates. This ensures that the bound oxygen is available for denitrification to occur.

As the concentration of suspended solids increases, sludge collects in the area below the inverted box 13. Common non-biodegradable items such as rubber latex, polymers, impregnated cellulose, man-made fibers, etc. are stored in the area 19 upstream of the screen 10.
gather at Excess sludge and non-biodegradable materials can be removed by suction from the tanker via openings 8 between runs.

Controlled outflow period from outlet 3 and electric blower 1f
The volume of liquid below the inlet water level when i11a is switched off allows the installation to handle peak inflows. This equipment is usually sufficient (e.g. the United Kingdom Royal Commission
dom Royal Commission) suitable for discharge into a stream or waterway if dilution water is available, or otherwise into the ground if the stones and concentration of influent sewage are within normal design operating conditions. The biological conglomerate within the facility is fully established, with no adverse effects from the biocide.

Although FIG. 3 does not show a typical network of surfaces 26 forming the coupling medium 14, 18 and/or IC 20, such surfaces may be arranged, for example, in closely bundled vertical tubes ( formed of molded sheets of lightweight plastic material (such as polypropylene), thus creating narrow channels between the sheets so that as the water level moves above and below the water level 17, liquid flows onto these surfaces and This allows it to be freely discharged from there.

FIG. 4 shows an enlarged cross-section of a typical coalescing medium 34 used in the final zone 24. The 1 ft. of fiber 34a acts to disrupt any laminar flow that would otherwise be created between plates 34b.

[Brief explanation of the drawing]

Figure 1 is a schematic longitudinal sectional view of the overall layout of this sewage treatment equipment, Figure 2 is a diagrammatic plan view from above at the height of the outlet of the equipment shown in Figure 1, and Figure 3 is a schematic longitudinal sectional view of the overall layout of this sewage treatment equipment. FIG. 4 is an enlarged partial cross-sectional view of a preferred type of bioagglomerate support system for the equipment of FIG. 1; FIG. 1: Layer 2: Inlet 3: Outlet 10 Niscreen 11a: Device 13: Inverted box 17: Liquid surface
19: First sedimentation chamber 20.18.14: Biological agglomerate support device 22: Return flow ducts 1 to 23: Valve device 24; Final sedimentation chamber 32: Coagulation medium, biological agglomerate support device

Claims (10)

[Claims] (1) A tank (1) containing liquid sewage up to the liquid surface (17) and gas above the liquid surface, and an inlet for the sewage to the tank (2)
, an outlet (3) from a tank of treated sewage, and a biological agglomerate support device in the tank, the equipment periodically raising said liquid surface (17) in the tank. and devices (11a), (13) for lowering and ensuring that the biological conglomerates on the support devices (14), (18), (20) are in alternating contact with liquid and gas. and sewage treatment equipment. (2) In the equipment set forth in claim 1, the biological agglomerate support devices (14), (18), and (20) are stationary within the tank to define a plurality of flow paths, through which the biological agglomerate support devices (14), (18), and (20) is the liquid surface (
17) can flow in one direction when rising, and the liquid surface (1
7) A facility characterized by being able to flow in the opposite direction when descending. (3) In the equipment according to claim 1 or 2, the device for periodically raising and lowering the liquid surface (17) in the tank includes an inverted box (13), and pressurizes it. A facility characterized in that it is capable of supplying air (via (12)). (4) The equipment according to claim 3, characterized in that the biological agglomerate support device (14) is located within the inverted box (13). (5) In the equipment according to any one of claims 1 to 4, the initial precipitation chamber (19) is provided with an inlet (
2) is located upstream of the main chamber of the facility, and the final settling chamber (24) is located downstream of the main chamber, close to the outlet (3). (6) In the equipment according to claim 5, each chamber has an individual biological agglomerate support device (14), (20), (1
8) and (32). (7) In the equipment according to claim 5 or 6, a screen (10) is disposed between the initial precipitation chamber (19) and the main room of the equipment, and the screen (10)
The equipment is characterized in that it filters and removes solid matter exceeding a certain size to prevent the solid matter from flowing into the main chamber. (8) The equipment according to claim 7, characterized in that regular backwashing of the screen (10) is caused by regular changes in the surface of the liquid in the tank. (9) In the equipment according to any one of claims 5 to 8, the liquid surface (17) reaches or exceeds its intended maximum height in the tank. The equipment is characterized in that the final precipitation chamber (24) is filled with the main chamber only when (10) In the equipment according to claim 9,
The final settling chamber includes a return flow duct (22) returning back to the main chamber and a valve arrangement (23) coupled to the return flow duct to prevent the flow of liquid from the main chamber to the final chamber via the duct. equipment, characterized in that the aggregation medium (32) in the final chamber (24) contains the fibers and breaks up the streamlines.