JPH03193122A - Filtration processing equipment - Google Patents

Abstract

PURPOSE:To prevent the choking of the flow paths of a membrane module by providing a prefilter having a large number of pore parts each having an opening cross-sectional area smaller than the inner diameter of each of the tubular membranes of the membrane module and having the total opening cross-sectional area equal to or larger than that of the membrane module on the upstream side of the membrane module. CONSTITUTION:Water to be treated containing impurity is passed through a tubular internal pressure type membrane module 8 having a large number of tubular membranes 6 provided thereto in parallel to be filtered. A prefilter 10 having a large number of pore parts 12 each having an opening cross-sectional area smaller than the inner diameter of each of the tubular membranes and having the total opening cross-sectional area equal to or larger than that of the membrane module 8 is provided on the upstream side of the membrane module 8. As a result, the choking of the flow paths of the tubular membranes of the membrane module can be prevented without requiring labor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a filtration device for filtering treated water containing impurities.

BACKGROUND OF THE INVENTION Conventional techniques have conventionally been used to biologically treat organic wastewater such as human waste containing a large amount of impurities and to separate it using a filtration membrane. As a filtration treatment apparatus in this case, there is one in which a plurality of tubular internal pressure type membrane modules each having a plurality of tubular membranes arranged side by side in a bundle are connected in series. The organic waste liquid passes through the tubular membrane of the membrane module under pressure, and is separated into filtered water and concentrated waste liquid at this time. If the treated water is passed through the membrane module while still containing a large amount of impurities, the tubular membrane of the membrane module will block the flow path. Therefore, the organic waste liquid is pretreated by injection of a chemical solution such as a polymer, drum screening, centrifugation, or a combination thereof before passing through the membrane module.

Problems to be Solved by the Invention However, impurities are not completely removed even with the above pretreatment, so impurities and surplus polymers, especially fibers, in the treated water become entangled and gradually enlarge as they flow through the flow path. This causes flow path blockage in the tubular membrane.

When a flow path blockage occurs in the middle of the tubular membrane, the inside of the tubular membrane is in a pressurized state, so concentration progresses further upstream and downstream of the flow path blockage point, and the inside of the tubular membrane where the flow path blockage has occurred is concentrated. The entire length is densely packed with muddy concentrated foreign matter.

In such a state, it becomes extremely difficult to clean the membrane module. In order to avoid this, if a fine-mesh strainer is installed upstream of the membrane module, the piping becomes complicated and the pressure loss becomes large.Furthermore, the frequency of cleaning increases to remove even the smallest impurities, which requires more effort. It will take a while.

The present invention solves the above-mentioned problem, and aims to provide a filtration treatment device that can prevent flow path clogging of a tubular membrane of a membrane module without requiring much effort.

Means for Solving the Problems In order to solve the above problems, the present invention has a plurality of holes having an opening cross-sectional area smaller than the inner diameter of the tubular membrane of the membrane module, and a total opening cross-section of the membrane module. A pre-filter whose area is equal to or larger than the total opening cross-sectional area of the membrane module is provided.

Effect With the above configuration, contaminants of a size that would block the flow path of the tubular membrane are removed by the prefilter before the membrane module, thereby preventing the flow path of the tubular membrane from being blocked. Since the total opening cross-sectional area of the pre-filter is greater than the total opening cross-sectional area of the membrane module, pressure loss is small.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 2, a pump 2 and a filtration device 3 are connected to a circulation tank 1 in which treated water X containing impurities is stored, and the treated water ing. For example, the pressure at the inlet of the filtration treatment device 3 is 4 kg/, n, and the pressure at the outlet is 1 kg/a+f.
It is said that The filtration processing device 3 includes six tubular filtration units 4
are connected in series. As shown in FIGS. 1 and 2, this tubular filtration unit 4 is a tubular internal pressure type in which 18 tubular membranes 6 each having a length of 3.8 m are arranged in parallel between backup plates 7 in a cylindrical case 5. It consists of a membrane module 8, a disc-shaped prefilter 10 disposed in an auxiliary case 9 upstream of the membrane module 8, and a connection joint 11. In the membrane module 8, the pressurized treated water X is separated into filtrated water and concentrated treated water by the tubular membrane 6, and the filtrated water is sent out from a filtration drain port (not shown). As shown in FIG. 3(a), the pre-filter 10 has holes in the shape of a truncated cone that are narrowed on the downstream side and whose narrow opening cross-sectional area at the downstream end is smaller than the inner diameter of the tubular membrane 6 (for example, about 172 holes). A plurality of portions 12 are formed. In the pre-filter 10, the total narrow opening cross-sectional area of the pores 12 is made equal to the total opening cross-sectional area of the tubular membrane 6 of the membrane module 8.

In the above configuration, the treated water X is supplied to the filtration treatment device 3 by the pump 2, and is separated into filtered water and concentrated treated water by the membrane module 8. In this case, although the treated water X contains impurities, a pre-filter 10 is provided upstream of each membrane module 8 in which a hole 12 having an opening cross-sectional area smaller than the inner diameter of the tubular membrane 6 is formed. Because of this, the prefilter 10 removes impurities that are large enough to potentially block the flow path of the tubular membrane 6 of the membrane module 8.

Further, since the total opening cross-sectional area of the pre-filter 10 is equal to the total opening cross-sectional area of the membrane module 8, the pressure loss due to the pre-filter 10 is small. Note that the prefilter 10 can be easily cleaned by removing the auxiliary case 9 from the tubular filtration unit 4 without much effort.

The shape of the hole 12 of the pre-filter IO is shown in FIG.
As shown in b), the shape may be tapered only on the upstream side, or as shown in FIG. It may be larger than the total opening cross-sectional area.

Furthermore, a wire mesh may be used as the pre-filter 10,
It may also be in the form of a triangular to hexagonal lattice. In this case, the size of the mesh is smaller than the inner diameter of the tubular membrane 6,
The total opening cross-sectional area of the wire mesh is greater than the total opening cross-sectional area of the membrane module 8.

Effects of the Invention As described above, according to the present invention, upstream of the membrane module,
Since the pre-filter is provided with a pore with an opening cross-sectional area smaller than the inner diameter of the tubular membrane, the pre-filter removes contaminants that may clog the flow path of the tubular membrane. Occlusion is prevented. Further, since the total opening cross-sectional area of the pre-filter is set to be greater than or equal to the total opening cross-sectional area of the membrane module, pressure loss due to the pre-filter is small. Since the pre-filter has a simple configuration, it can be manufactured at low cost and can be easily cleaned without much effort.

[Brief explanation of drawings]

The drawings show a filtration treatment apparatus according to an embodiment of the present invention, in which Fig. 1 is a schematic diagram showing the flow of treated water, Fig. 2 is an enlarged view of the main part with a partial cutout, and Fig. 3 is a diagram showing the pores. FIG. 3 is a cross-sectional view showing the shape. 3... Filtration processing device, 6... Tubular membrane, 8... Membrane module, 10... Pre-filter, 12... Hole section,
X... Treated water.

Claims (1)

[Claims] 1. A filtration treatment device that filters treated water containing impurities by passing it through a tubular internal pressure type membrane module in which a plurality of tubular membranes are arranged in parallel, and the tubular membrane module is provided upstream of the membrane module. A filtration processing device comprising a pre-filter having a plurality of pores each having an opening cross-sectional area smaller than the inner diameter of a membrane, and a total opening cross-sectional area of the pre-filter having a total opening cross-sectional area greater than or equal to the total opening cross-sectional area of the membrane module.