Biocide-enhanced mechanical treatment of water

1 . A method for controlling the growth of microorganisms in water systems comprising the steps of:

a) treating the water system with a hydrodynamic-based water treatment device; and

b) adding at least one biocide to the water system being treated, to inhibit the growth of the microorganisms

2 . The method of claim 1 , wherein the hydrodynamic-based water treatment device creates hydrodynamic cavitation in the water passing through the hydrodynamic water treatment device.

3 . The method of claim 1 , wherein the wherein the hydrodynamic-based water treatment device creates shear in the water passing through the hydrodynamic water treatment device.

4 . The method of claim 1 , wherein the hydrodynamic-based water treatment device creates hydrodynamic cavitation and shear in the water passing through the hydrodynamic water treatment device.

5 . The method of claim 1 , wherein the water system is industrial process water.

6 . The method of claim 5 , wherein the industrial process water is a paper process system.

7 . The method of claim 1 wherein the water system is in a natural or man-made surface or sub-surface aquatic system.

8 . The method of claim 1 , wherein the biocide is selected from the group consisting of 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-methyl4-isothiazolin-3-one (CMIT), 2-methyl4-isothiazolin-3-one (MIT), 2-n-octyl-4-isothiazolin-3-one; 4,5-dichloro-2-(n-octyl)4-isothiazolin-3-one; 1,2-benzisothiazolin-3-one; glutaraldehyde; ortho-phthalaldehyde; 2,2-dibromo-3-nitrilopropionamide (DBNPA) ; 2-bromo-2-nitrostyrene, 2-nitrostyrene; 2-bromo4′-hydroxyacetophenone; methylene bisthiocyanate (MBTC); 2-(thiocyanomethylthio)benzothiazole; 3-iodopropynyl-N-butylcarbamate; n-alkyl dimethyl benzyl ammonium chloride; didecyl dimethyl ammonium chloride; alkenyl dimethylethyl ammonium chloride; 4,5-dichloro-1,2-dithiol-3-one; decylthioethylamine; 2-bromo-2-nitropropane-1, 3-diol; n-dodecylguanidine hydrochloride; n-dodecylguanidine acetate; 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride; 1,2-dibromo-2,4-dicyanobutane; bis(1,4-bromoacetoxy)-2-butene; bis(1,2-bromoacetoxy)ethane; bis(trichloromethyl)sulfone; diiodomethyl-p-tolylsulfone; sodium ortho-phenylphenate; tetrahydro-3,5-dimethyl-2H-1,3,5-hydrazine-2-thione; cationic salts of dithiocarbamate derivatives; 4-chloro-3-methyl-phenol; 2,4,4′-trichloro-2′-hydroxy-diphenylether; poly(oxyethylene(dimethyliminio) ethylene-(dimethyliminio)ethylene dichloride.

9 . The method of claim 1 wherein the biocide comprises an quaternary alkyldimethylbenzyl ammonium chloride amine.

10 . The method of claim 1 wherein the biocide comprises halogenated amine.

11 . The method of claim 1 wherein the biocide comprises glutaraldehyde.

12 . The method in claim 1 , wherein two or more biocides are used in combination with a hydrodynamic water treatment device.

13 . The method of claim 1 wherein the amount of biocide used is less than about 7 mg per liter.

14 . A method for controlling the growth of microorganisms in water comprising the steps of adding an amount of biocide to the water that is less than the amount needed to inhibit microorganisms present in said water and treating the water with a hydrodynamic-based water treatment device that imparts sufficient hydrodynamic forces on the water and microorganisms therein to inhibit said microorganisms at an extent or at a rate greater than in the absence of the biocide