Industry News » Metawater Co. Ltd. Patent Issued for Distributor Pipe And Trickling Filter (USPTO 10,358,365)

2019 AUG 5 (VerticalNews) -- By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Tabata, Masao (Tokyo, JP); Kurinami, Tomoki (Tokyo, JP), filed on September 6, 2016, was published online on August 5, 2019.

The patent's assignee for patent number 10,358,365 is Metawater Co. Ltd. (Tokyo, Japan).

News editors obtained the following quote from the background information supplied by the inventors

Field of the Invention

The present invention relates to a distributor pipe having a plurality of outlets, and a trickling filter using the distributor pipe.

Description of Related Art

Conventionally, various sewage treatment systems, which treat sewage such as household wastewater or industrial wastewater, have been utilized by using a conventional activated sludge process, a trickling filter process or the likes. For example, in a sewage treatment system using a conventional activated sludge process, aeration treatment of supplying oxygen to many types of aerobic microorganisms present in a reaction tank is performed while sewage to be treated is flown into the reaction tank. Accordingly, organic substances included in the sewage in the reaction tank are subjected to decomposition treatment by action of the aerobic microorganisms, and as a result, quality of the treated water can be stably obtained.

Further, in a wastewater treatment plant adopting such a sewage treatment system, an aerobic treatment, which is represented by an activated sludge process, is carried out. In this activated sludge process, after organic components in wastewater are subjected to decomposition treatment, a process of discharging the treated wastewater to rivers and the like is performed. The trickling filter process is one of such aerobic treatment methods, and in the trickling filter process, a filtering medium made of a bed of rocks, stones, plastic, or the like is packed into a trickling filter, and a layer of biofilm is formed on the surface of the filtering medium. In the trickling filter, wastewater is supplied to a filter bed from a top portion of the apparatus, and the wastewater is subjected to aerobic treatment by the biofilm formed on the filtering medium. In this specification, the filtering medium packed into the trickling filter will be referred to as a 'filter bed'.

To distribute wastewater onto the filter bed, a fixed dosing tank distributor, a fixed nozzle distributor, or a rotary distributor is used. Of these distributors, the rotary distributor has been mainly adopted because of its equipment cost and uniformity of distribution (sees Non Patent Literature 1). According to a method of arranging this conventional rotary distributor, a support pillar along a height direction is arranged on a bottom portion of a trickling filter, and the rotary distributor is arranged on a top portion of this support pillar. The arranged rotary distributor sprays the wastewater all over the filter bed by rotating its arms with an electric motor or by using reaction force of the spraying.

Further, for the fixed dosing tank distributor or the fixed nozzle distributor, a top spraying form not provided with a support pillar has been proposed (Patent Literature 1 & Patent Literature 2). In the fixed dosing tank described in Patent Literature 1, a method of arranging the filtering medium for dispersion is adopted in order to ensure uniformity of distribution. Further, in the fixed type nozzle form described in Patent Literature 2, a method of arranging a dispersion tool is adopted in order to ensure uniformity of distribution.

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent

Technical Problem

However, according to the inventors, in the trickling filters described in 'Guidelines and Commentary for Designing Sewage Plants', supervised by Ministry of Construction, issued by Japan Sewage Works Association in 1972, Japanese Patent Application Laid-open No. H10-328683 and Japanese Patent Application Laid-open No. 2007-160280, fluctuation in spraying strength has been found in the distribution of the spraying strength, and uniform distribution over the filter bed has been difficult to be achieved. Further, in sewage treatment plants, fluctuation in processing load problematically makes uniform distribution difficult.

It is an object of the present invention to provide a distributor pipe which can reduce fluctuation in spraying strength and achieve uniform distribution for a filter bed in a trickling filter, and a trickling filter which uses the distributor pipe.

Solution to Problem

A distributor pipe according to one aspect of the present invention includes: a main pipe including a cylindrical part; and a plurality of branch pipes communicating with the main pipe and arranged, on a cylindrical curved surface of the main pipe, side by side along a longitudinal direction of the main pipe, wherein a pipe diameter ratio D.sub.1/D.sub.0 of a pipe diameter D.sub.1 of the branch pipe to a pipe diameter D.sub.0 of the main pipe is greater than 0.2 and less than 0.8, and the plurality of branch pipes are arranged according to: respective effluent flow ratios, at a time a liquid flows into the main pipe in a predetermined flow velocity range, determined in accordance with respective arrangement orders of the plurality of branch pipes along a direction in which the liquid flows and along the longitudinal direction of the main pipe; and respective areas of circular or hollow-circular sections allotted to the plurality of branch pipes.

The distributor pipe according to one aspect of the present invention in which the predetermined flow velocity range is greater than 0.5 m/s and not greater than 5.0 m/s.

The distributor pipe according to one aspect of the present invention in which the number of the branch pipes is five to nine.

The distributor pipe according to one aspect of the present invention in which the ratio D.sub.1/D.sub.0 of the pipe diameter D.sub.1 of the branch pipe to the pipe diameter D.sub.0 of the main pipe is 0.5 to 0.7.

A trickling filter according to another aspect of the present invention includes: the distributor pipe according to the above-described invention; and a filter bed performing a biological treatment to treatment target water discharged from the distributor pipe, wherein an area in a circular or hollow-circular section allotted to each of the branch pipes is a spraying area along a horizontal plane over the filter bed.

The trickling filter according to another aspect of the present invention in which the distributor pipe of the trickling filter is held by being suspended from above the filter bed.

Advantageous Effects of Invention

The distributor pipe and the trickling filter according to the present invention can reduce fluctuation in spraying strength and achieve uniform distribution for a filter bed.

The claims supplied by the inventors are:The invention claimed is

1.A distributor pipe, comprising: a main pipe including a cylindrical part; a plurality of branch pipes communicating with the main pipe and arranged, on a cylindrical curved surface of the main pipe, side by side along a longitudinal direction of the main pipe; and an influent pipe from which liquid is provided to the main pipe, wherein the influent pipe provides the liquid to the main pipe with a flow velocity range greater than 0.5 m/s and not greater than 100 m/s and a pipe diameter ratio D.sub.1/D.sub.0 of a pipe diameter D.sub.1 of the branch pipe to a pipe diameter D.sub.0 of the main pipe is greater than 0.2 and less than 0.8 such that respective effluent flow ratios which are ratios of effluent rates from the respective branch pipes to an influent rate to the main pipe is set so that the closer the branch pipe is to a downstream-side of the liquid the larger the effluent flow ratio becomes, and the plurality of branch pipes are arranged with intervals having predetermined interval lengths between one another according to: the effluent flow ratios and spraying allotment areas where the liquid is sprayed from the plurality of branch pipes, wherein the cylindrical part of the main pipe is a hollow cylindrical part having an upstream influent end and a downstream effluent end, each at opposite ends of the main pipe, and the hollow cylindrical part of the main pipe having a substantially constant diameter that extends to the outermost edge of the effluent end of the main pipe, a discharge outlet nozzle is provided at the outermost end of the hollow cylindrical part at the effluent end of the main pipe, such that the discharge nozzle is in direct communication with the substantially constant diameter at the outermost edge of the effluent end of the main pipe, for discharging liquid to the outside from the hollow cylindrical part of the main pipe, and a pipe diameter D.sub.2 of the discharge outlet nozzle is smaller than the pipe diameter D.sub.1 of the branch pipes.

2. The distributor pipe according to claim 1, wherein the flow velocity range is greater than 0.5 m/s and not greater than 5.0 m/s.

3. The distributor pipe according to claim 1, wherein the number of the branch pipes is five to nine.

4. The distributor pipe according to claim 2, wherein the number of the branch pipes is five to nine.

5. The distributor pipe according to claim 1, wherein the ratio D.sub.1/D.sub.0 of the pipe diameter D.sub.1 of the branch pipe to the pipe diameter D.sub.0 of the main pipe is 0.5 to 0.7.

6. A trickling filter, comprising: the distributor pipe according to claim 1; and a filter bed performing a biological treatment to treatment target water discharged from the distributor pipe, wherein the spraying allotment area in each of the branch pipes is a spraying area along a horizontal plane over the filter bed.

7. A trickling filter, comprising: the distributor pipe according to claim 2; and a filter bed performing a biological treatment to treatment target water discharged from the distributor pipe, wherein the spraying allotment area in each of the branch pipes is a spraying area along a horizontal plane over the filter bed.

8. A trickling filter, comprising: the distributor pipe according to claim 3; and a filter bed performing a biological treatment to treatment target water discharged from the distributor pipe, wherein the spraying allotment area in each of the branch pipes is a spraying area along a horizontal plane over the filter bed.

9. A trickling filter, comprising: the distributor pipe according to claim 4; and a filter bed performing a biological treatment to treatment target water discharged from the distributor pipe, wherein the spraying allotment area in each of the branch pipes is a spraying area along a horizontal plane over the filter bed.

10. The trickling filter according to claim 6, wherein the distributor pipe of the trickling filter is held by being suspended from above the filter bed.

11. The trickling filter according to claim 7, wherein the distributor pipe of the trickling filter is held by being suspended from above the filter bed.

12. The trickling filter according to claim 8, wherein the distributor pipe of the trickling filter is held by being suspended from above the filter bed.

13. The trickling filter according to claim 9, wherein the distributor pipe of the trickling filter is held by being suspended from above the filter bed.

14. The distributor pipe according to claim 5, wherein a pipe diameter ratio D.sub.2/D.sub.0 is greater than 0 and smaller than 0.65."


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