Water treatment process and apparatus

Claim 2

A process for electrolytically treating contaminated water containing suspended and dissolved impurities comprising the steps of: passing the contaminated water vertically upward through an upright column having a water inlet port adjacent the lower end thereof and a water outlet port adjacent the upper end thereof, wherein between the inlet and outlet port, a plurality of electrically conductive perforate plates are disposed in the column in a plane essentially perpendicular to the longitudinal axis thereof and electrically insulated therefrom, the transverse dimensions of the plate approximating those of the column so that essentially all of the contaminated water being passed through the column passes through perforations in the plates; generating variable pulsating electrical signals of opposite signs; and, supplying a variable pulsating electrical signal of a first sign to individual ones of a first set of the plates while simultaneously supplying a variable pulsating electrical signal of the opposite sign to individual ones of a second, alternating set of the plates to create a pulsating electrical field between the plates.

Claim 3

The process of claim 1 wherein water downstream of said column is passed through a flocculation chamber of such capacity that the average residence time of the water therein is at least about 20 minutes.

Claim 4

The process of claim 2 wherein water in said chamber is subjected to gentle agitation.

Claim 5

The process of claim 3 wherein said water is caused to follow a non-linear path through said chamber, occasioning said agitation.

Claim 6

The process of claim 1 comprising the further step of, prior to passing the contaminated water through the column, adjusting the pH of the contaminated water to within a range of from about 8.0 to about 10.0.

Claim 7

The process of claim 5 which comprises the further step of removing gross impurities from the contaminated water by passing it through a screen of abut 30 mesh or larger prior to its admission to said column.

Claim 8

The process of claim 2 wherein downstream of said chamber water is passed through clarification and filtering means to remove suspended matter therefrom.

Claim 9

A process for electrolytically treating contaminated water containing as contaminants organic and inorganic suspended solids, dissolved metal salts, and cyanide complexes of metals comprising the steps of: pretreating the contaminated water by adjusting its pH to within the range of from about 8.0 to about 10.0 and by screening the contaminated water through a screen of about 30 mesh or larger; passing the contaminated water vertically upward through an upright column having a water inlet port adjacent the lower end thereof and a water outlet port adjacent the upper end thereof, wherein, between the inlet and outlet port, a plurality of electrically conductive perforate plates are disposed in the column in a plane essentially perpendicular to the longitudinal axis thereof and electrically insulated therefrom, the transverse dimensions of the plates approximating those of the column so that essentially all of the contaminated water passed through the column passes through perforations in said plates; generating variable pulsating electrical signals of opposite signs with variable pulsating electrical signal means; applying a variable pulsating electrical signal of a first sign to individual ones of a first set of the plates while simultaneously applying a variable pulsating electrical signal of the opposite sign to individual ones of a second, alternating set of the plates to create a pulsating electrical field between the plates; passing contaminated water which flows from the outlet port of the column through a flocculation chamber of such capacity that the average residence time of the water therein is at least about 20 minutes; and, subsequently, passing the water through clarification and filtering means to remove suspended solids therefrom.

Claim 10

A process for electrolytically treating contaminated water containing as contaminants organic and inorganic suspended solids, dissolved metal salts, and cyanide complexes of metals comprising the steps of: pretreating the contaminated water by adjusting its pH to within the range of from about 8.0 to about 10.0 and by screening the contaminated water through a screen of about 30 mesh or larger; passing the contaminated water vertically upward through an upright column having a water inlet port adjacent the lower end thereof and a water outlet port adjacent the upper end thereof, wherein, between the inlet and outlet port, a plurality of electrically conductive perforate plates are disposed in the column in a plane essentially perpendicular to the longitudinal axis thereof and electrically insulated therefrom, the transverse dimensions of the plates approximating those of the column so that essentially all of the contaminated water passed through the column passes through perforations in said plates; generating variable pulsating electrical signals of opposite signs with variable pulsating electrical signal means; applying a variable pulsating electrical signal of a first sign to individual ones of a first set of the plates while simultaneously applying a variable pulsating electrical signal of the opposite sign to individual ones of a second, alternating set of the plates to create a pulsating electrical field between the plates; passing contaminated water which flows from the outlet port of the column through a flocculation chamber of such capacity that the average residence time of the water therein is at least about 20 minutes; and, subsequently, passing the water through clarification and filtering means to remove suspended solids therefrom.

Claim 11

The process of claim 8 wherein the voltage of the pulsating electrical signal is varied so as to maintain a constant current density on the plates of the column.

Claim 12

The process of claim 8 which additionally comprises the step of sensing conductivity of said water upstream from said column, generating a signal proportional to said conductivity, and employing said signal to vary input A.C. voltage to means by which said pulsating signal is generated in inverse relation to said conductivity.

Claim 13

The process of claim 1, wherein the voltage of the pulsating electrical signals is varied so as to maintain a constant current density on the plates of the column.

Claim 14

The process of claim 1, further comprising the step of sensing conductivity of said water upstream from the column, generating a signal proportional to said conductivity, and employing said signal to vary input A.C. voltage to means by which said pulsating signal is generated in inverse relation to said conductivity.

Claim 15

The process of claim 1, further including the step of maintaining current density on the perforate plates substantially at a constant by varying the voltage of the pulsating electrical signals.

Claim 16

The process of claim 1, wherein the magnitude of said pulsating electrical field is at least about 10 5 volts/centimeter in the immediate vicinity of said plates.

Claim 17

The process of claim 1, wherein said pulsating electrical signals are generated in the form of a square wave.