Method for treating wastewater and wastewater sludge using a percarboxylic acid

Patent metadata

Field	Value
Publication number	US-11535539-B2
Application number	US-201716344856-A
Country	US
Kind code	B2
Filing date	Nov 17, 2017
Priority date	Nov 18, 2016
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A method for treating a wastewater or a wastewater sludge includes adding performic acid to the wastewater and/or the waster sludge as an odor controlling agent and/or corrosion controlling agent.

First claim

The invention claimed is:

1. A method for treating a wastewater and/or a wastewater sludge stream comprising dissolved sulfides, said method comprising:
measuring a concentration of the dissolved sulfides in the wastewater and/or the wastewater sludge stream;
adding performic acid as a treating chemical to the wastewater and/or the wastewater sludge stream as an odor controlling agent and/or a corrosion controlling agent in an amount of 1-12 ppm calculated as an active concentration of performic acid, wherein the active concentration of the performic acid is 8%-14% calculated as weight to volume of the treating chemical; and
adjusting the amount of the treating chemical based on the concentration of the dissolved sulfides measured;
wherein adding the treating chemical decreases the concentration of the dissolved sulfides within 5-10 minutes to below 5 ppm, and wherein said treating chemical is added to a headworks of a wastewater treatment plant, an influent of the wastewater treatment plant and/or a wastewater treatment plant solids applications or a piping leading to or from the wastewater treatment plant solids applications.

2. The method according to claim 1 , wherein the active concentration of the performic acid is at least 9% calculated as weight to volume of the treating chemical.

3. The method according to claim 1 , wherein the wastewater and/or the wastewater sludge stream is a stream in a municipal wastewater collection or treatment application, in a municipal sludge collection or treatment application, or in an industrial wastewater application.

4. The method according to claim 1 , wherein the concentration of the dissolved sulfides in the wastewater and/or the wastewater sludge stream is measured at a point, to which the wastewater and/or the wastewater sludge stream is flown after adding the treating chemical.

5. The method according to claim 1 , wherein adjusting the amount of the treating chemical is conducted by modifying a rate of adding the treating chemical to the wastewater and/or the wastewater sludge stream based on the concentration of the dissolved sulfides measured.

6. The method according to claim 1 , wherein the treating chemical is added continuously to the wastewater and/or the wastewater sludge stream in at least one process location.

7. The method according to claim 2 , wherein the active concentration of the performic acid is at least 10% calculated as weight to volume of the treating chemical.

8. The method according to claim 1 , wherein adding the treating chemical decreases the concentration of the dissolved sulfides to less than 2 ppm within 5-10 minutes in the wastewater and/or the wastewater sludge stream.

9. The method according to claim 8 , wherein adding the treating chemical decreases the concentration of the dissolved sulfides to less than 1 ppm within 5-10 minutes in the wastewater and/or the wastewater sludge stream.

Assignees

• Kemira Oyj

Inventors

• Allen James Currie
• Mariga Tafadzwa

Classifications

• C02F11/00

  Treatment of sludge; Devices therefor · CPC title

• C02F2303/02

  Odour removal or prevention of malodour · CPC title

• C02F2209/26

  H2S · CPC title

• C02F11/06

  by oxidation (incinerators for burning waste liquors, e.g. sulfite liquor from paper-making plant F23G7/04) · CPC title

• C02F2101/101

  Sulfur compounds · CPC title