Method for purifying septic tank effluent

Claim 1

A method of purifying septic tank effluent flowing at substantially atmospheric pressure, comprising passing liquid effluent by gravity from a septic tank successively through a plurality of serially-connected tanks, the first of which tanks in said series contains a filter for mechanically filtering solids from the liquid as it passes through said first tank, intermittently feeding ozone gas through each of the remainder of said serially-connected tanks during the passage of said liquid through said remaining tanks, collecting the ozonated liquid in a reservoir after passage thereof through the last of said serially-connected tanks, allowing the ozonated liquid to flow by gravity out of said reservoir from an opening adjacent the upper end thereof, conveying excess ozone gas from said remaining tanks to said septic tank, and periodically backwashing said filter by reversing the flow of liquid through said first tank and the filter therein, and returning the backwash liquid to said septic tank, said backwashing step including using at least some liquid from said reservoir for backwashing said filter.

Claim 2

A method of purifying septic tank effluent flowing at substantially atmospheric pressure, comprising passing liquid effluent by gravity from a septic tank successively through a plurality of serially-connected tanks, the first of which tanks in said series contains a filter for mechanically filtering solids from the liquid as it passes through said first tank, intermittently feeding ozone gas through each of the remainder of said serially-connected tanks during the passage of said liquid through said remaining tanks, collecting the ozonated liquid in a reservoir after passage thereof through the last of said serially-connected tanks, allowing the ozonated liquid to flow by gravity out of said reservoir from an opening adjacent the upper end thereof, conveying excess ozone gas from said remaining tanks to said septic tank, and periodically backwashing said filter by reversing the flow of liquid through said first tank and the filter therein, and returning the backwash liquid to said septic tank, said backwashing step including using at least some liquid from said reservoir for backwashing said filter.

Claim 7

A method of purifying septic tank effluent, comprising filtering the liquid effluent from a septic tank through a porous filter element, passing the filtered fluid by gravity successively through a series of vertically disposed ozonating tanks, and for an overall distance of at least sixteen feet, intermittently supplying ozone gas to each of said ozonating tanks adjacent the lower ends thereof, conveying excess ozone gas from the upper ends of said ozonating tanks back to the associated septic tank to preozonate the liquid therein before it is filtered through said porous filter element, accumulating the filtered and ozonated liquid in a reservoir after its discharge from the last ozonating tank in said series thereof, and allowing said liquid to overflow from said reservoir, and at atmospheric pressure, into a leach field surrounding said reservoir.

Claim 8

A method of purifying septic tank effluent, comprising filtering the liquid effluent from a septic tank through a porous filter element, passing the filtered fluid by gravity successively through a series of vertically disposed ozonating tanks, and for an overall distance of at least sixteen feet, intermittently supplying ozone gas to each of said ozonating tanks adjacent the lower ends thereof, conveying excess ozone gas from the upper ends of said ozonating tanks back to the associated septic tank to preozonate the liquid therein before it is filtered through said porous filter element, accumulating the filtered and ozonated liquid in a reservoir after its discharge from the last ozonating tank in said series thereof, and allowing said liquid to overflow from said reservoir, and at atmospheric pressure, into a leach field surrounding said reservoir.