Treatment of high peroxide waste streams

Patent metadata

Field	Value
Publication number	US-2019127247-A1
Application number	US-201716305959-A
Country	US
Kind code	A1
Filing date	May 25, 2017
Priority date	Jun 2, 2016
Publication date	May 2, 2019
Grant date	—

Abstract

A method of reducing a concentration of hydrogen peroxide from wastewater includes diluting the wastewater with water having a lower concentration of hydrogen peroxide than the wastewater to produce a diluted wastewater, contacting the diluted wastewater with a dissolved iron compound at an acidic pH to form a partially treated wastewater having a lower concentration of hydrogen peroxide than the diluted wastewater, and precipitating iron solids from the partially treated wastewater by raising a pH of the partially treated wastewater to form a neutralized partially treated wastewater.

First claim

What is claimed is:

1 . A method of reducing a concentration of hydrogen peroxide in wastewater, the method comprising:
diluting the wastewater to produce a diluted wastewater; contacting the diluted wastewater with a dissolved iron compound at an acidic pH to form a partially treated wastewater having a lower concentration of hydrogen peroxide than the diluted wastewater; and precipitating iron-containing compounds from the partially treated wastewater by raising a pH of the partially treated wastewater to form a neutralized partially treated wastewater.

2 . The method of claim 1 , further comprising utilizing at least a portion of iron-containing compounds precipitated from the partially treated wastewater as a source of the dissolved iron compound.

3 . The method of claim 2 , comprising contacting the diluted wastewater with the dissolved iron compound at the acidic pH in a first reaction tank, precipitating the iron-containing compounds from the partially treated wastewater in a second reaction tank, and recycling the precipitated iron-containing compounds from the second reaction tank to the first reaction tank.

4 . The method of claim 1 , wherein diluting the wastewater includes diluting the concentration of hydrogen peroxide in wastewater to less than about 2.2 wt % prior to introducing the diluted wastewater into the first reaction tank.

5 . The method of claim 1 , comprising contacting the diluted wastewater with the dissolved iron compound at the acidic pH in a first reaction tank, precipitating the iron-containing compounds from the partially treated wastewater in a second reaction tank, and diluting the wastewater with solids lean effluent from the second reaction tank.

6 . The method of claim 5 , wherein diluting the wastewater includes diluting the concentration of hydrogen peroxide in wastewater to less than about 2.2 wt % prior to introducing the diluted wastewater into the first reaction tank.

7 . The method of claim 1 , further comprising removing residual hydrogen peroxide from the partially treated wastewater by treating the partially treated wastewater with catalytic activated carbon to form a treated water.

8 . (canceled)

9 . (canceled)

10 . (canceled)

11 . The method of claim 1 , further comprising:
introducing the partially treated wastewater into a microfilter concentration tank; and periodically filtering a portion of the partially treated wastewater from the microfilter concentration tank through a microfilter.

12 . The method of claim 11 , further comprising recycling microfilter concentrate separated from the partially treated wastewater by the microfilter to the microfilter concentration tank.

13 . The method of claim 11 , further comprising diluting the wastewater with a portion of filtrate produced from the partially treated wastewater in the microfilter.

14 . A system for removing hydrogen peroxide from wastewater, the system comprising:
a first reaction tank having an inlet fluidly connectable to a source of the wastewater; a source of dilution water having a lower concentration of hydrogen peroxide than the wastewater in fluid communication with the inlet of the first reaction tank; a source of ferrous salt in fluid communication with the first reaction tank; a source of acid in fluid communication with the first reaction tank; a second reaction tank having an inlet in fluid communication with an outlet of the first reaction tank; and a source of a base in fluid communication with the second reaction tank.

15 . The system of claim 14 , further comprising a recycling system configured to recycle iron containing compounds from the second reaction tank to the first reaction tank.

16 . The system of claim 15 , further comprising a control system configured to regulate addition of the ferrous salt and recycle of the iron containing compounds to the first reaction tank maintain a dissolved iron concentration of between about 2 g/l and about 6 g/l in the first reaction tank.

17 . The system of claim 16 , wherein the control system is further configured to regulate addition of the acid to the first reaction tank to maintain a pH of between about 1 and about 3 in the first reaction tank.

18 . The system of claim 17 , wherein the control system is further configured to regulate addition of the base to the second reaction tank to maintain a pH of between about 6 and about 8 in the second reaction tank.

19 . The system of claim 14 , further comprising a water recycling system configured to recycle solids lean effluent from the second reaction tank to the inlet of the first reaction tank, the solids lean effluent forming at least a portion of the dilution water.

20 . The system of claim 14 , further comprising a microfilter concentration tank having an inlet in fluid communication with an outlet of the second reaction tank.

21 . The system of claim 20 , further comprising a solids/liquid separation unit having an inlet in fluid communication with an outlet of the microfilter concentration tank.

22 . The system of claim 21 , further comprising a concentrate recycle system configured to recycle solids separated from the neutralized partially treated wastewater in the solids/liquid separation unit to the microfilter concentration tank.

23 . The system of claim 21 , further comprising a filtrate recycle system configured to recycle filtrate formed from the neutralized partially treated wastewater in the solids/liquid separation unit to the inlet of the first reaction tank.

24 . The system of claim 23 , further comprising a filtrate holding tank in fluid communication between the solids/liquid separation unit and the inlet of the first reaction tank, the filtrate holding tank including a first outlet in fluid communication with the first reaction tank and a second outlet in fluid communication with a discharge stream that discharges liquid from the system.

25 . The system of claim 14 , further comprising a vessel including catalytic activated carbon having an inlet in fluid communication with an outlet of the second reaction tank.

26 - 29 : (canceled)

Assignees

• Evoqua Water Tech Llc

Inventors

• Sassaman Jr Frank L
• Berger David L
• Karrs Stanley R

Classifications

• C02F1/725

  by catalytic oxidation · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title

• C02F2101/10

  Inorganic compounds · CPC title

• C02F1/5245 Primary

  using basic salts, e.g. of aluminium and iron · CPC title

• C02F9/00

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