# US 2014/0151307 A1 · Acidification pre-treatment for uv water disinfection

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- Number: US 2014/0151307 A1
- Document ID: US20140151307A1
- Status: Published application
- Kind: A1
- Application number: 13/692,034
- Filed: 2012-12-03
- Published: 2014-06-05
- Earliest claimed: 2012-12-03
- Assignees: Earth Renaissance Technologies, LLC
- Inventors: Marcus G. Theodore; Terry R. Gong
- Web page: https://patentgrep.com/patent/US20140151307A1

## CPC

- C02F 1/32: with ultraviolet light
- C02F 1/004: {using large scale industrial sized filters}
- C02F 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58)
- C02F 2101/20: Heavy metals or heavy metal compounds
- 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

A pre-treatment method injecting sulfur dioxide into waters containing suspended solids to undergo ultra violet disinfection to form sulfurous acid (H2SO3) to self-agglomerate and precipitate solids from the wastewater for settling or filtration removal and provide acid to reduce bicarbonate and mineral scaling and microbial buildup on ultraviolet light tubes to improve their performance.

## Claims

### Claim 1

A pre-treatment method for ultraviolet light disinfection of water streams having suspended solids in a liquid fraction with ultraviolet light irradiation from a uv light bank with uv light tubes, comprising:
a. injecting sulfur dioxide (SO2) into the water streams before undergoing ultraviolet light disinfection at a point before the light tubes to form a sulfurous acid reducing solution, which dissociates to produce hydrogen ions, sulfites, bisulfites and free SO2 at an acid concentration below that required for disinfection, but sufficient to chemically dewater and agglomerate suspended solids without polymers, acid leach heavy metals from the solids into acidified liquid fractions and reduce bicarbonate levels to reduce alkalinity scaling and iron deposit buildup on the uv light tubes,
b. removing and disposing of the suspended solids from the acidified liquid fraction forming recovered treated water,
c. passing the recovered treated water between the light tubes for exposure to ultraviolet light sufficient for disinfection to produce a disinfected recovered treated wastewater, and
d. adjusting the pH of the disinfected recovered treated water for reuse.

### Claim 2 (depends on 1)

A pre-treatment method for ultraviolet light disinfection water streams according to claim 1, wherein the sulfur dioxide is generated onsite and injected continuously into the water streams at about a pH <6.9 and >4.0 by passing either all or a portion of the water stream through a sulfur burner before undergoing ultraviolet light disinfection.

### Claim 3 (depends on 2)

A pre-treatment method for ultraviolet light disinfection of water streams according to claim 2, including land applying the disinfected recovered water to raise crops or photo biomass.