Method of monitoring bulk (total) microbiological activity in process streams

• US 7,981,679 B2
• Filed: 11/20/2007
• Issued: 07/19/2011
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Nalco Company (Ecolab, Inc.)
• Inventors: Rice, Laura E.
• Primary Examiner(s): Sines; Brian J
• Application Number:
  US11/943,162
• Publication Number:
  US 20080199969A1
• Time in Patent Office: 1,337 Days
• Field of Search: 436/55, 436/62
• US Class Current: 436/55
• CPC Class Codes: G01N 33/1806 biological or chemical oxygen demand (BOD or COD)
• CPC Class Codes: G01N 33/1893 using flow cells
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/20 Oxygen containing
• CPC Class Codes: Y10T 436/209163 Dissolved or trace oxygen or oxygen content of a sealed environment

Abstract

An apparatus and method for monitoring and controlling microbiological activity in a process stream by measuring dissolved oxygen is disclosed.

Claims

1. A method for monitoring and controlling bulk (total) microbiological water activity in a process stream comprising:

a. connecting an apparatus to a process stream, wherein said apparatus comprises a flow cell containing a plurality of openings, wherein at least one opening is a flow cell inlet for fluid drawn from said process stream and at least one opening is a flow cell outlet for fluid exiting said flow cell, a DO probe attached to one of said openings, optionally an ORP probe attached to one of said openings, optionally a cleaning device attached to one of said openings, optionally a first conduit attached to the flow cell inlet, optionally a second conduit attached to the flow cell outlet, and optionally a valve associated with said flow cell;

b. drawing fluid from said process steam into said flow cell excluding adding oxygen and/or nutrients to the drawn fluid;

c. opening the valve of said apparatus to allow fluid to be drawn into said flow cell;

d. taking a first measurement, the first measurement measuring at least once the DO concentration of said process stream with said DO probe, and wherein prior to each measuring of the first measurement the surface of said DO probe is cleaned;

e. closing the valve of said apparatus to prevent fluid from being drawn into said flow cell;

f. taking a second measurement, the second measurement measuring at least once the DO concentration of the fluid inside said apparatus with said DO probe, and wherein prior to each measuring of the second measurement the surface of said DO probe is cleaned;

g. calculating a Δ

DO reading between step (d) and step (f);

h. correlating at least said Δ

DO value in step (g) with bulk (total) microbiological activity in said process stream; and

i. controlling the amount of said microbiological activity by adding an effective amount of a treatment containing one or more oxidizing biocides to the process stream and/or an effective amount of a treatment containing one or more non-oxidizing biocides and optionally a mixture containing an n-hydrogen compound, an oxidizing biocide, and optionally a buffer to the process stream.

2. The method of claim 1 wherein said process stream is a papermaking process stream or a hydroentangling non-woven process stream.

3. The method of claim 2 wherein said hydroentangling non-woven process stream is part of process for making a fiberglass mat.

4. The method of claim 1, wherein the n-hydrogen compound contains at least one of the following:

an ammonium salt, ammonium sulfate, ammonium acetate, ammonium bicarbonate, ammonium bromide, ammonium carbonate, ammonium chloride, ammonium citrate, ammonium nitrate, ammonium oxalate, ammonium persulfate, ammonium phosphate, ammonium sulfate, ferric ammonium sulfate, and ferrous ammonium sulfate.

5. The method of claim 1, wherein the n-hydrogen compound contains at least one of the following:

succinimide, cyanamide, dicyanamide, melamine, ethanolamine, ethylenediamine, diethanolamine, triethanolamine, triethylenetetramine, dibutylamine, tributylamine, glutamine, diphenylamine, hydrazine, urea, thiourea, N-methylurea, acetylurea, ethylcarbamate, 1,3-dimethylbiuret, methyl phenylbiuret, isocyanuric acid, barbituric acid, 6-methyluracil, 2-imidazoline, 5,5-dimethylhydantoin, 2-pyrimidinone, benzamide, phthalimide, N-ethylacetamide, azetidin-2-one, 2-pyrrolidone, caprolactam, sulfamic acid, sulfamide, p-toluenesulfonamide, phenyl sulfonamide, dimethyl sulfinimine, isothiazolene-1,1-dioxide, orthophosphoryl triamide, pyrophosphoryl triamide, phenyl phosphoryl-bis dimethylamide;

boric acid amide, methanesulfonaimide, melamine, pyrrolidone, hydantoin, acetanilide, acetmide, biuret, allophanate, pyrrole, indole, guanidine, biguanidine, and primary and secondary nitrogen containing polymers.

6. The method of claim 1 wherein the non-oxidizing biocide contains at least one of the following:

2,2-dibromo-3-nitrilopropionamide (DBNPA), glutaraldehyde, methylene bisthiocyanate (MBTC), thiazole derivatives, isothiazolinone derivatives, 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MT), 1,2-benzisothiazolin-3-one (IT), 2-bromo-2-nitro-propane-1,3-diol (Bronopol), a long chain quaternary ammonium compound, an aliphatic diamine, a guanidine, biguanidine, n-dodecylguanidine hydrochloride (DGH), n-alkyl dimethyl benzyl ammonium chloride, didecyl dimethyl ammonium chloride, 1,2-dibromo-2,4-dicyanobutane, 2,2-dibromo-3-nitrilopropionamide (DBNPA), bis(trichloromethyl)sulfone, 4,5-dichloro-1,2-dithiol-3-one, 2-bromo-2-nitrostyrene, 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), and 2-methyl-4-isothiazolin-3-one (MIT).

7. The method of claim 1 wherein the non-oxidizing biocide is added subsequent to the mixture.