# US 10,766,788 B2 · Waste water treatment system with buffering device and waste water treatment method therefor

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- Number: US 10,766,788 B2
- Document ID: US10766788B2
- Status: Granted
- Kind: B2
- Application number: 16/342,984
- Filed: 2018-06-29
- Published: 2020-02-20
- Granted: 2020-09-08
- Earliest claimed: 2017-06-29
- Assignees: Aquacell INC.
- Applicants: Aquacell INC.
- Inventors: Xufeng Tian
- Web page: https://patentgrep.com/patent/US10766788B2

## CPC

- C02F 1/043: {Details}
- C02F 1/048: {Purification of waste water by evaporation}
- C02F 1/008: {Control or steering systems not provided for elsewhere in subclass C02F}
- C02F 1/52: by flocculation or precipitation of suspended impurities {(C02F1/463 takes precedence)}
- C02F 2001/5218: {Crystallization}
- C02F 2209/001: Upstream control, i.e. monitoring for predictive control
- C02F 2209/01: Density
- C02F 2209/02: Temperature
- C02F 2209/05: Conductivity or salinity
- C02F 2209/06: pH
- C02F 2209/11: Turbidity
- C02F 2209/42: Liquid level
- C02F 2301/046: Recirculation with an external loop
- C02F 2303/22: Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence)
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)

## Abstract

Disclosed is a waste water treatment system with a buffering device, the system comprising a waste water pretreatment device, an evaporator, a circulating crystallizer, a crystal filtration device and a water removal device which communicate with each other in sequence, and further comprising a primary buffering device and a secondary buffering device, wherein one end of the primary buffering device is in bi-directional communication with the circulating crystallizer, and the other end thereof is connected to the evaporator; and the secondary buffering device is in bi-directional communication with the circulating crystallizer. Further disclosed is a waste water treatment method for a waste water treatment system with a buffering device.

## Claims

### Claim 1

A waste water treatment system with a buffering device, comprising a waste water pretreatment device, an evaporator, a circulation crystallizer, a crystal filtration device, a dehydration device, a primary buffering device and a secondary buffering device;
the waste water pretreatment device, the evaporator, the circulation crystallizer, the crystal filtration device, the dehydration device are sequentially communicated;
one end of the primary buffering device is in bidirectional communication with the circulation crystallizer and the other end is connected with the evaporator; the secondary buffering device is in bidirectional communication with the circulation crystallizer;
both the primary buffering device and the secondary buffering device include a plurality of buffers, each of the plurality of buffers is provided with a detection element related to a liquid level, and the circulation crystallizer is provided with a detection element related to a concentration;
the system further comprises a controller that is in data communication with a central controller of the system and is also connected to each detection element related to the liquid level and the detection element related to the concentration, respectively.

### Claim 2 (depends on 1)

The waste water treatment system with a buffering device according to claim 1, wherein an outlet and an inlet of the circulation crystallizer, a first opening and a second opening of the primary buffering device, an outlet and an inlet of the secondary buffering device, and an inlet and an outlet of each buffer are all provided with a power connection device that controls a fluid flow in the buffering devices with the controller.

### Claim 3 (depends on 1)

The waste water treatment system with a buffering device according to claim 1, wherein the detection element related to the liquid level comprises a liquid level sensor, and the detection element related to the concentration is one or more of a density sensor, a conductivity meter, and a turbidity sensor.

### Claim 4 (depends on 1)

The waste water treatment system with a buffering device according to claim 1, wherein a main structure of the buffer is a can-shaped structure, and a viewing port is opened on the can-shaped structure and the can-shaped structure is provided with a stirring device.

### Claim 5 (depends on 1)

The waste water treatment system with a buffering device according to claim 1, wherein one end of the primary buffering device is in bidirectional communication with the circulation crystallizer and the other end is connected with the evaporator, specifically as follows:
an outlet of the evaporator is connected to a first opening of the primary buffering device and a first branch port of the circulation crystallizer is connected to a second opening of the primary buffering device;
the secondary buffering device is in bidirectional communication with the circulation crystallizer, specifically as follows:
a second branch port of the circulation crystallizer is also connected to an inlet of the secondary buffering device and an outlet of the secondary buffering device is connected to an inlet of the circulation crystallizer.

### Claim 6 (depends on 1)

A waste water treatment method using the waste water treatment system with a buffering device according to claim 1, comprising the steps of:
S1, starting the waste water treatment system other than the primary buffering device and the secondary buffering device;
S2, in a crystallization process of the circulating crystallizer, existing one or more of the following operating conditions, wherein this step is begun when a stable evaporator operation is achieved, and the following operating conditions are maintained via the controller:
operating condition 1: when a characteristic value of a solution in the circulation crystallizer >a predetermined threshold K, a liquid in the primary buffering device is controlled to flow to the circulation crystallizer;
operating condition 2: when the characteristic value of the solution in the circulation crystallizer <a predetermined threshold K, the liquid in the circulation crystallizer is controlled to flow to the primary buffering device;
operating condition 3: when the characteristic value of the solution in the circulation crystallizer >a predetermined threshold M, the liquid in the circulation crystallizer is controlled to flow to the secondary buffering device;
operating condition 4: when the characteristic value of the solution in the circulation crystallizer <a predetermined threshold M, the liquid in the circulation crystallizer is controlled to flow to the secondary buffering device;
S3, opening an outlet of the circulation crystallizer and generating a crystalline salt for precipitating after a condensed liquid enters the crystal filtration device and the dehydration device in sequence when the characteristic value of the solution in the circulation crystallizer reaches a predetermined crystallization threshold.

### Claim 7 (depends on 6)

The waste water treatment method according to claim 6, wherein between step S1 and step S2, there is also a step of controlling a liquid in the evaporator to flow to the primary buffering device until the characteristic value of the liquid in the primary buffering device reaches a predetermined low threshold.

### Claim 8 (depends on 7)

The waste water treatment method according to claim 7, wherein after operating condition 1, there is also included with a step of controlling the liquid in the evaporator to flow to the primary buffering device until the characteristic value of the liquid in the primary buffering device reaches a predetermined low threshold.

### Claim 9 (depends on 7)

The waste water treatment method according to claim 7, wherein in operating condition 2, the liquid in the evaporator flows to the primary buffering device until a total liquid amount for the characteristic value of the liquid in the primary buffering device reaches a predetermined high threshold.

### Claim 10 (depends on 2)

A waste water treatment method using the waste water treatment system with a buffering device according to claim 2, comprising the steps of:
S1, starting the waste water treatment system other than the primary buffering device and the secondary buffering device;
S2, in a crystallization process of the circulating crystallizer, existing one or more of the following operating conditions, wherein this step is begun when a stable evaporator operation is achieved, and the following operating conditions are maintained via the controller:
operating condition 1: when a characteristic value of a solution in the circulation crystallizer >a predetermined threshold K, a liquid in the primary buffering device is controlled to flow to the circulation crystallizer;
operating condition 2: when the characteristic value of the solution in the circulation crystallizer <a predetermined threshold K, the liquid in the circulation crystallizer is controlled to flow to the primary buffering device;
operating condition 3: when the characteristic value of the solution in the circulation crystallizer >a predetermined threshold M, the liquid in the circulation crystallizer is controlled to flow to the secondary buffering device;
operating condition 4: when the characteristic value of the solution in the circulation crystallizer <a predetermined threshold M, the liquid in the circulation crystallizer is controlled to flow to the secondary buffering device;
S3, opening the outlet of the circulation crystallizer and generating a crystalline salt for precipitating after a condensed liquid enters the crystal filtration device and the dehydration device in sequence when the characteristic value of the solution in the circulation crystallizer reaches a predetermined crystallization threshold.

### Claim 11 (depends on 10)

The waste water treatment method according to claim 10, wherein between step S1 and step S2, there is also a step of controlling a liquid in the evaporator to flow to the primary buffering device until the characteristic value of the liquid in the primary buffering device reaches a predetermined low threshold.

### Claim 12 (depends on 11)

The waste water treatment method according to claim 11, wherein after operating condition 1, there is also included with a step of controlling the liquid in the evaporator to flow to the primary buffering device until the characteristic value of the liquid in the primary buffering device reaches a predetermined low threshold.

### Claim 13 (depends on 11)

The waste water treatment method according to claim 11, wherein in operating condition 2, the liquid in the evaporator flows to the primary buffering device until a total liquid amount for the characteristic value of the liquid in the primary buffering device reaches a predetermined high threshold.