Water treatment device and water treatment method

Abstract

Provided is a water treatment device, particularly a water treatment device for preparing fresh water using a semi-permeable membrane. The water treatment device obtains treated water from a variety of treated waters, has a small drainage burden on the environment, and at the same time, separates The membrane has less pollution, the cleaning frequency and the cost of bactericide are low, and it can operate stably. The water treatment device is characterized by having a pretreatment unit X, a membrane separation unit Y and a membrane separation unit Z. The pretreatment unit A part B1 of B is separated into permeate water C1 and concentrated water C2. The membrane separation unit Z separates the mixed water into permeate water E1 and concentrated water E2. The mixed water is mixed with at least the remaining part B2 of the treated water B and The treated water D is different from the treated water A, and the water treatment device has a pipeline for returning at least a part of the concentrated water C2 to the pretreatment unit X.

Description

technical field [0001] The present invention relates to a water treatment device using a semipermeable membrane unit for obtaining fresh water by treating seawater, river water, groundwater, and wastewater treatment water. water treatment method. Background technique [0002] With the gradual deterioration of the water environment in recent years, water treatment technology has become more important than ever, and in particular, technology using separation membranes has been widely used. In order to obtain drinking water, industrial water, agricultural water, etc., the purification of river water, lake water, etc. is mainly carried out, but in the Middle East where water resources are few and oil-based heat resources are very rich, seawater with evaporation as the center is gradually developed. Desalination. However, even in regions other than the Middle East where heat sources are not abundant, the demand for desalination of seawater has increased. Especially since 1990, ...

AI Technical Summary

Problems solved by technology

In contrast, high-pressure reverse osmosis membranes for seawater system water treatment have been developed with the main goal of reducing the required energy, and it is difficult to apply technologies that reduce the water permeability of the membrane and prevent fouling that has a negative impact on the performance, or Such countermeasures are not usually implemented

Therefore, when the concentrated water from the low-pressure reverse osmosis membrane derived from sewage treatment water is supplied to the high-pressure reverse osmosis membrane, there is a problem that the growth of organisms is easily promoted, and biofouling of the high-pressure reverse osmosis membrane is likely to be caused.

In addition, as in image 3 In the case where the low-pressure reverse osmosis membrane installed on the upstream side of the water treatment device causes biofouling, there is a risk that the fouling substance will be mixed into the high-pressure reverse osmosis membrane on the downstream side, resulting in not only the low-pressure reverse osmosis membrane, but also the high-pressure reverse osmosis membrane. The performance of the reverse osmosis membrane is also reduced

In order to prevent these situations from happening, it is necessary to frequently clean the low-pressure reverse osmosis membrane and the high-pressure reverse osmosis membrane, and put in a bactericide. Although as shown in Patent Document 3, a method of reducing costs by reusing the cleaning solution is proposed, it will essentially lead to Increased operating costs

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