Waste water treatment plant
AssigneeKlargester Environmental Engineering Ltd.
InventorGerald Rowland
Life of this patent
Estimating the term…
Abstract
To desludge the final settlement tank of a waste water treatment plant which includes a bio zone equipped with slowly rotating rotors on which biomass deposited from the waste water is digested by microorganisms as the biomass is periodically exposed to air, the level of liquid in the final settlement tank is raised above that in the bio zone so that gravity induced desludging can occur. One of the rotating rotors can be equipped with water lifting means to generate the required hydraulic head for desludging. Skimming off of scum from the surface of the water in the final settlement tank can also be effected using the hydraulic head between the tank and the bio zone.
Claims10
In a waste water treatment plant including
- first tank means defining a bio zone,
- means to feed waste water to said bio zone tank means to generate a liquid level therein,
- at least one rotor means rotatable about an axis and dipping only partially below the liquid level in the bio zone tank means,
- drive means to turn said at least one rotor means about said axis to periodically convey an area of said rotor means through said waste water and then through the air above said liquid level,
- second tank means defining a settlement zone,
- means to feed liquid from said bio zone to said settlement zone, and duct means to feed purified liquid from the settlement zone away from the plant, and
- desludging means in said second tank means to suck sludge collected in the second tank means back into the bio zone,
- the improvement which includes
- arranging said means which feed liquid from said bio zone to said settlement zone to lift the liquid above the liquid level in the bio zone, whereby
- said desludging means operates on the head of water existing between the bio zone and the settlement zone.
A waste water treatment plant including
- first tank means defining a bio zone,
- means to feed waste water to said bio zone tank means to generate a first liquid level therein,
- a plurality of rotating members, each rotatable about an axis and each dipping only partially below the first liquid level in the bio zone tank means,
- drive means to turn said rotating members about said axis to periodically convey an area of each of said members through said waste water and then through the air above said liquid level,
- second tank means defining a final settlement zone,
- means to feed liquid from said bio zone to said final settlement zone to define a second liquid level therein, and duct means to feed purified liquid from the final settlement zone away from the plant,
- desludging means in said second tank means to suck sludge collected in the second tank means back into the bio zone,
- water lifting means on at least one of said rotating members arranged to lift water to a third level above that of the second liquid level,
- means to collect water from said lifting means and feed it to the final settlement zone,
- said desludging means including a sludge return pipe opening close to the bottom of the final settlement zone and leading to a stage in the plant upstream of the final settlement zone, and
- valve means in said sludge return pipe for controlling the flow therethrough.
Dependencies are inferred from the claim text.