Lenox Institute for Research, Inc.

Lenox Institute of Water Technology, Inc.

Other

Milos Krofta

Robert P Langdon

A compact dissolved-air-flotation (DAF) clarifier treats raw water with suspended solid contaminants first in a flocculator at the center of an annular tank where microscopic air bubbles float flocked contaminants to form a floating sludge layer. The flocculator has a fixed, cylindrical sidewall. A first clarification, calming and degassing occur here. The water then flows radially outwardly into the tank with a straight cylindrical outer wall where further quiet clarification occurs. A third level of clarification occurs in a lower portion of the tank, specifically, within a set of fixed, inclined lamellae, where a final clarification occurs. The bottom wall of the tank has a set of apertures which allow a gravity flow of clarified water through a layer of pressurized gas to an underlying collection compartment. A set of rotating paddles push the sludge layer up a ramp to an opening in an inclined discharge conduit. The paddles extend generally from the region over the full surface area of the tank, to its outer wall, which is preferably cylindrical. The ramp twists about its radial axis, being shallower and longer at its outer edge and steeper and shorter at its inner edge. An offset drive operating through a belt rotates the paddles, a movable cylindrical wall surrounding the lower portion of the fixed flocculator wall, and at least one scraper secured at one end to the movable wall and extending radially under the lamellae.

Three zone dissolved air floatation clarifier with fixed lamellae and improved paddle-and-ramp sludge removal system

A compact dissolved-air-flotation (DAF) clarifier and clarification process utilize three zones for clarification which operate in sequence in a single clarifier. Raw water with suspended solids enters a flocculator at the center of an annular tank where microscopic air bubbles introduced to the inflow float flocked contaminants to form a floating sludge layer. A first clarification, calming and degassing occur here. The water then flows radially outwardly into the tank where further quiet clarification occurs. A third level of clarification occurs in a lower portion of the tank, specifically, in a set of plate-like lamellae, radial and conical, which form inclined channels where a final clarification occurs. The bottom wall of the tank has a set of apertures which allow a gravity flow of clarified water through a layer of pressurized gas to an underlying collection compartment. Level sensors control a valve in the clarified outflow line and an air bleed from the pressurized gas layer to regulate liquid levels in the clarifier. A set of rotating paddles push the sludge layer up a ramp to an inclined discharge conduit. Alternatively, a suction head with a mechanical skimmer sweeps around the tank to draw the sludge through a central hollow pipe to a discharge conduit. An offset drive operating through a belt rotates the sludge removal mechanism and the lamellae.

Three zone dissolved air flotation clarifier with improved efficiency

Raw feed water is continuously clarified at a large throughput rate in a single, shallow tank using a flotation process carried out simultaneously in multiple sectors of the tank. Raw water feeds into a rotating trough. A fixed manifold system in the trough dispenses pressurized water containing dissolved air to release microscopic air bubbles. A set of headers each radially extend outwardly from the rotating trough. Each header distributes water and bubbles to a sector of the tank with a net zero velocity. A set of rotating extractors each receive clarified water from the bottom of a preceding sector. A set of scoops skim floated sludge from the water in the tank. The sludge is lifted, as by the rotation of the scoop and/or by a pumped conduit, over the rotating trough to a sludge outlet pipe. In one form the scoop has at least two blades each with an eccentrically located, radially extending compartment that receives, lifts, and then dumps the skimmed sludge as the scoop rotates about its axis.

High capacity single tank water clarification method

High capacity single tank water clarification system

A two stage raw water clarifier with first stage flotation and second stage filtration divides at least the lower portion of a flotation tank into independent cells. A branched slotted conduit located in a filter medium in each cell collects clarified water. Valves control the flow of clarified water from each branched conduit either to a clarified water ring conduit or to a first filtrate/backwash ring conduit connected to a storage tank. The filter media is preferably a dual media, a layer of anthracite or activated carbon over a layer of sand. High cell walls and inclined baffles in each cell retain the filter media during backwashing. The baffles also slow the flotation process. A decompression valve for pressurized water with dissolved air has a very narrow annular slot in the flow path through the valve to create microscopic air bubbles of optimal size for the flotation. A movable member sets this annular slot at a proper value. A mechanical or pneumatic actuator moves the member periodically to open the slot and flush out trapped particles.

Water clarifier with first filtrate isolation, improved backwashing and

An apparatus and method for de-inking waste paper pulp using a foam flotation process to recycle printed waste paper for the manufacture of new paper. Pulped printed paper is fed as a slurry to an inlet of a shallow tank. Internal guide walls in the tank establish a flow path from the inlet to an outlet. The walls are sized and positioned to create a generally uniform cross-sectional flow area. A plurality of modules are disposed along the flow path. Each module includes at least one injector that aerates the flow and an extractor that removes floated ink foam. A portion of the flow from each module is recycled to an upstream module, preferably by a conduit and associated pump. In a preferred form, an injector (or injectors) alone located at the inlet is fed by the next downstream module and an extractor alone is located near the outlet. The invention also includes a main recycling loop from the downstream end of the flow path to the upstream end. This main recycling loop has a large flow rate compared to the recycled flow between the modules.

Apparatus and method for deinking waste paper pulp

A compact water treatment plant has at least one vertical stack of dissolved air flotation (DAF) type clarifiers. Raw water is directed first to a single stage clarifier with a shallow tank. Its output is fed to an underlying two stage clarifier, preferably one with tall, mutually isolated cells, inclined baffles over a filtration medium in each cell, a cell-by-cell backwash capability, and an arrangement for isolating the first filtrate from the clarified water. Preferably, there are two such stacks in side-by-side array to provide a peak-load capacity, redundancy, and extreme compactness. Also preferably, clarified water from the single stage clarifier flows to the two stage clarifier via a bioreactor and an associated DAF clarifier. A source of aeration defines an upper, aerobic zone in the reactor where bacteria act on organic contaminants (COD's and BOD's). Strips of a deep pile, woven textile form a biocarrier. The strips oscillate in the tank. A portion of the bioliquor and sludge from the bioreactor-dedicated clarifier recirculate through a lower, anoxic zone of the bioreactor for denitrification.

Compact clarifier system for municipal waste water treatment

A tank receives raw water for clarification by flotation. An array of lamellae define a set of generally vertically oriented channels with solid side walls. Flotation occurs in each channel. The channels are preferably inclined. With a round tank, a frame rotates an interlocking array of radial and concentric lamellae. A stationary raw water inlet distribution box fills the channels with raw treated water. An aligned clarified water collection box withdraws clarified water. A stationary skimmer directs floating sludge to a removal conduit with a variable pitch screw conveyor. Sliding seals on the lamellae isolate individual channels or groups of channels as they move through the tank. The channels lock and move columns of water through the tank with substantially no turbulence.

Lamellar apparatus and method for clarifying water

A tank with a generally flat, rectilinear bottom wall receives raw water for clarification by flotation. An array of lamellae define a set of generally vertically oriented channels. Flotation occurs in each channel. The channels are preferably inclined. A pair of endless chains or the like rotate alongside the tank to move a succession of mutually spaced, paddle-like lamellae through the tank. Sliding seals secured to the edge or edges of the lamellae isolate individual channels, or groups of channels, as they move through the tank. The channels lock and move a column of water through the tank with substantially no turbulence.

Lamellar clarifier with rectilinear tank

Water clarifying apparatus has a cylindrical tank where particulate contaminants suspended in raw water are separated using flotation techniques. The treatment capacity of such a unit is increased several times, with no increase in the size of the tank, by using a set of concentric, mutually spaced, conical plates positioned in the flotation tank. The increase is proportional to the combined area of the plates when projected onto a horizontal plane, the overlap of the projection producing an area which is greater than that of the horizontal plane without plates. The plates rotate about the tank, preferably in unison with a (i) header that distributes equal quantities of raw water to each annular zone in the tank defined by the conical plates and (ii) a scoop for removing the contaminants which form a floated sludge layer. To accommodate this increased clarification capacity the clarifying apparatus also includes a screw conveyor located in a discharge pipe of the floated sludge scoop, which rotates at a greater speed than and in the opposite direction of the scoop.

Sludge collection apparatus for a water clarifier

Water clarifying apparatus has a cylindrical tank where particulate contaminants suspended in raw water are separated using flotation techniques. The treatment capacity of such a unit is increased by using a set of concentric, mutually spaced, conical plates positioned in the flotation tank. The apparatus utilizes air dissolving tubes operating in parallel that have common feeds and discharges coupled through three way valves operated to pressurize a closed volume of water with high pressure air in one tube while reloading and discharging the other tube.

Apparatus for aerating water

Water clarifying apparatus has a cylindrical tank where particulate contaminants suspended in raw water are separated using flotation techniques. The treatment capacity of such a unit is increased several times, with no decrease in the size of the tank, by using a set of concentric, mutually spaced, conical plates positioned in the flotation tank. The increase is proportional to the combined area of the plates when projected onto a horizontal plane, the overlap of the projection producing an area which is greater than that of the horizontal plane without plates. The plates rotate about the tank, preferably in unison with a (i) header that distributes equal quantities of raw water to each annular zone in the tank defined by the conical plates and (ii) a scoop for removing the contaminants which form a floated sludge layer. To accommodate this increased clarification capacity the clarifying apparatus also includes (1) a screw conveyor located in a discharge pipe of the floated sludge scoop, (2) an infrared sludge detection array operating in conjunction with a window in the side wall of the tank to sense the sludge-water interface and the turbidity of the water below the interface, and in response thereto, to coordinate and control the operation of the apparatus, and (3) air dissolving tubes operating in parallel that have common feeds and discharges coupled through three way valves operated to pressurize a closed volume of water with high pressure air in one tube while reloading and discharging the other tube. Where a sandbed filter is used at the bottom of the tank, the apparatus also includes clarified water extraction pipes imbedded in the sand and a steam backwashing system.

Water clarifying apparatus

An apparatus and method for stabilizing sludge such as the sludge produced by municipal waste water treatment plants includes thickening of the sludge to a dry solid content in the range of 3% to 8% before feeding it to at least one comparatively small reactor tank that extends horizontally and has an inlet and outlet adjacent opposite end walls. The system preferably utilizes multiple tanks stacked one above the other and connected in series. The tanks have an in-built mixer that sweeps through the interior of the tank. The mixer is eccentrically mounted so that its mixing members carry the sludge through the uppermost portion of the tank interior and are spaced from the bottom surface of the tank. A sparger is located either in the inlet or in the bottom clearance of the tank to introduce microscopic bubbles of oxygen and ozone into the sludge. A pressure regulating valve controls the flow of the stabilize sludge from the uppermost reactor tank. The pressure regulating valve and the metering pump together maintain a hyperbaric pressure within the tanks.

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Lenox, MA, United States of America

Milos Krofta