Treatment system and method for drinking water

Patent metadata

Field	Value
Publication number	US-11718549-B2
Application number	US-202117799951-A
Country	US
Kind code	B2
Filing date	Apr 13, 2021
Priority date	Feb 10, 2021
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

A water treatment system comprises a flow path through a first activated carbon filter, a second activated carbon filter downstream of the first activated carbon filter, a particulate filter downstream of the second activated carbon filter, for example a ceramic membrane, and a UV sterilizer downstream of the particulate filter. Ozone is introduced into the process water ahead of a water storage vessel for storing treated water produced by the system. A recycle subsystem is periodically operated to withdraw treated water from the water storage vessel to form recycled water, introduce the recycled water to the water lines upstream of the UV sterilizer, and return the recycled water to the water storage vessel. A main programmable logic controller (PLC) controls a flow of the process water through the water treatment system and controls the recycle subsystem.

First claim

The invention claimed is:

1. A water treatment system comprising:
a system inlet arrangeable in fluid communication with a source of water to be treated and so as to admit process water to the water treatment system, the system inlet in fluid communication with a plurality of water lines for transporting the process water through the system along a flow path where the process water flows through
a first activated carbon filter,
a second activated carbon filter downstream of the first activated carbon filter,
a particulate filter downstream of the second activated carbon filter, and
a first UV sterilizer downstream of the particulate filter;

a water storage vessel at an end of the flow path for storing water produced by the system;
an ozone subsystem comprising an ozonator for making ozone and at least one junction along the flow path for introducing the ozone into the process water, wherein the ozone subsystem is configured to withdraw water from the water storage vessel and add ozone to the withdrawn water to form ozonated water, and wherein the ozone subsystem is configured to introduce the ozonated water to the process water through a first branch water line connected to the flow path at a first junction located between the second activated carbon filter and the first UV sterilizer and upstream or downstream of the particulate filter, through a second branch water line connected to the flow path at a second junction located between the first activated carbon filter and the second activated carbon filter, and through a third branch water line connected to the flow path at a third junction located upstream of the first activated carbon filter;
a system outlet in fluid communication with the water storage vessel for delivering the water from the water storage vessel to a location outside the water treatment system;
a recycle subsystem that is periodically operable to withdraw water from the water storage vessel to form recycled water, introduce the recycled water to the water lines upstream of the UV sterilizer, and return the recycled water to the water storage vessel; and,
a main programmable logic controller (PLC) for controlling a flow of the process water through the water treatment system and for controlling the recycle subsystem.

2. The water treatment system of claim 1 , wherein the ozone subsystem comprises a first eductor in the first branch water line, a second eductor in the second branch water line, and a third eductor in the third branch water line and wherein the first eductor, the second eductor and the third eductor introduce the ozone to the water from the water storage vessel to form the ozonated water in the first branch water line, the second branch water line and the third branch water line.

3. The water treatment system of claim 2 , wherein the ozone subsystem further comprises a first UV oxidizer in the first branch water line downstream of the first eductor, a second UV oxidizer in the second branch water line downstream of the second eductor, and a third UV oxidizer in the third branch water line downstream of the third eductor.

4. The water treatment system of claim 1 , wherein the process water contains ozone in a range of from 0.05 to 2 ppm.

5. The water treatment system of claim 1 , further comprising a water quality analyzer for measuring at least one water quality parameter of the process water, the water quality analyzer in electronic communication with the main programmable logic controller, the main programmable logic controller programmed to compare the at least one water quality parameter measured by the at least one sensor to an index value of the at least one water quality parameter and to operate the water treatment system based on the comparison.

6. The water treatment system of claim 5 , wherein the at least one water quality parameter comprises one or more of residual chlorine, total chlorine, total organic carbon, total dissolved solids, pH, conductivity and temperature.

7. The water treatment system of claim 6 , wherein the at least one water quality parameter comprises a plurality of water quality parameters.

8. The water treatment system of claim 5 , wherein the main programmable logic controller comprises or is in communication with an ozone controller that controls an amount of ozone injected into the process water based on the comparison.

9. The water treatment system of claim 8 , wherein the system comprises an in-line ozone detector that measures an ozone concentration and wherein the ozone controller controls an amount of ozone introduced into the process water based on the ozone concentration.

10. The water treatment system of claim 1 , wherein the recycle subsystem is automatically operable on a periodic time basis.

11. The water treatment system of claim 1 , wherein the first UV sterilizer is operable when the recycle subsystem is operable.

12. The water treatment system of claim 1 , wherein the water storage vessel is a variable-volume water storage vessel comprising at least one water level sensor that signals a shutdown of a flow of the process water into the system when water level in the vessel is at or exceeds a first predetermined water level and signals a switch on of the flow of process water into the system when the water level in the vessel is at or lower than a second predetermined water level lower than the first predetermined water level.

13. The water treatment system of claim 1 , wherein the system further comprises a water holding tank between the system inlet and the first activated carbon filter, and wherein the water holding tank is a variable-volume water storage vessel comprising at least one water level sensor that signals a shutdown of a flow of the process water into the system when water level in the vessel is at or exceeds a first predetermined water level and signals a switch on of the flow of the process water into the system when the water level in the vessel is at or lower than a second predetermined water level lower than the first predetermined water level.

14. The water treatment system of claim 1 , wherein the second activated carbon filter contains bamboo-derived activated carbon and/or coconut-derived activated carbon.

15. The water treatment system of claim 1 , wherein the particulate filter comprises a ceramic microfiltration membrane or a ceramic ultrafiltration membrane.

16. The water treatment system of claim 1 , further comprising a second UV sterilizer between the water storage vessel and the system outlet.

Assignees

• Univ Tsinghua

Inventors

• Sun Wenjun
• Shi Jingdong

Classifications

• C02F9/00 Primary

  Multistage treatment of water, waste water or sewage · CPC title

• C02F1/008

  Control or steering systems not provided for elsewhere in subclass C02F · CPC title

• C02F1/283

  using coal, charred products, or inorganic mixtures containing them · CPC title

• C02F1/32

  with ultraviolet light · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title