Wastewater treatment

Claim 1

A method for substantially upgrading the pollutant removal capability of wastewater treatment plants that include a primary treatment unit for the removal of settleable and floatable solids from said wastewater; an activated sludge processing tank, a clarifier disposed downstream from said processing tank and conduit means for recirculating solids from said clarifier to said processing tank, said method including the steps of, a. providing a .Iadd.single stage .Iaddend.biological treatment unit between said processing tank and said clarifier, b. supplying wastewater containing carbonaceous pollutants measured as BOD 5 and ammonia nitrogen in a weight ratio of at least about 3.6:1 respectively to said processing tank from said primary treatment unit, c. storing said wastewater in said processing tank, d. supplying said wastewater at a substantially constant predetermined rate from said processing tank to said .Iadd.single stage .Iaddend.biological treatment unit, e. said biological treatment unit including .[.not more than a single.]. .Iadd.at least one .Iaddend.rotatable shaft supporting a plurality of partially submerged biological contactors having surface area for the growth and maintenance of organisms, f. creating a flow of said wastewater through said biological treatment unit in a direction generally perpendicular to said rotatable shaft .Iadd.so as to feed the organisms on said contactor surfaces substantially equally, .Iaddend. g. rotating said shaft to impart a predetermined peripheral velocity to said biological contactors to alternately expose said surface area to wastewater and an oxygen containing atmosphere, h. said predetermined rate and peripheral velocity being chosen to simultaneously oxidize at least about 83 weight percent of said BOD 5 and at least about 46 weight percent of said ammonia nitrogen on the same surface area of said biological .[.contacts,.]. .Iadd.contactors, .Iaddend. i. said substantially constant predetermined rate being from about 0.4 to about 2.5 gallons/day/sq.ft. of said surface area, and j. inactivating said conduit means to prevent recirculation of solids from said clarifier to said processing tank.

Claim 2

A method for substantially upgrading the pollutant removal capability of wastewater treatment plants that include a primary treatment unit for the removal of settleable and floatable solids from said wastewater; an activated sludge processing tank, a clarifier disposed downstream from said processing tank and conduit means for recirculating solids from said clarifier to said processing tank, said method including the steps of, a. providing a .Iadd.single stage .Iaddend.biological treatment unit between said processing tank and said clarifier, b. supplying wastewater containing carbonaceous pollutants measured as BOD 5 and ammonia nitrogen in a weight ratio of at least about 3.6:1 respectively to said processing tank from said primary treatment unit, c. storing said wastewater in said processing tank, d. supplying said wastewater at a substantially constant predetermined rate from said processing tank to said .Iadd.single stage .Iaddend.biological treatment unit, e. said biological treatment unit including .[.not more than a single.]. .Iadd.at least one .Iaddend.rotatable shaft supporting a plurality of partially submerged biological contactors having surface area for the growth and maintenance of organisms, f. creating a flow of said wastewater through said biological treatment unit in a direction generally perpendicular to said rotatable shaft .Iadd.so as to feed the organisms on said contactor surfaces substantially equally, .Iaddend. g. rotating said shaft to impart a predetermined peripheral velocity to said biological contactors to alternately expose said surface area to wastewater and an oxygen containing atmosphere, h. said predetermined rate and peripheral velocity being chosen to simultaneously oxidize at least about 83 weight percent of said BOD 5 and at least about 46 weight percent of said ammonia nitrogen on the same surface area of said biological .[.contacts,.]. .Iadd.contactors, .Iaddend. i. said substantially constant predetermined rate being from about 0.4 to about 2.5 gallons/day/sq.ft. of said surface area, and j. inactivating said conduit means to prevent recirculation of solids from said clarifier to said processing tank.