Purifying plant.

group present invention relates to a system for providing the mechanical and biological treatment of waste water.

The problems associated with pollution have taken, in recent years, more and more important. To preserve the environment and minimize the importance of waste discharged into the natural media, many industries need to purge water purification plants, to the extent possible, the enclosed water discharge the waste pollutants. Similarly, the effluent water by communities must undergo a purification treatment before being rejected in the natural media.

It has already been proposed many sewage treatment plants whose dimensions can be quite different according to the content and importance in waste water to be purified.

In the case of industries particularly polluting, such as, for example, oil refineries or certainés chemical industries, it has been required using sets considerable purification, storage vessels containing, plants for mechanical, chemical, incinerators or lagoons biological treatment. On the contrary, in the case of using the forks polluted, installations of much smaller scale may prove satisfactory.

Among the cleaning methods that are currently known, the biological purification methods of particular significance in the case very frequent where BOD or biological oxygen demand rejected product is important.

Gold, with regard to the biological purification, the existing facilities are far from perfect. Indeed, waste water treatment plants by activated sludge is well suited for large stations and continually monitored. In contrast, the experiments of recent years have shown that such applied to units too small and unattended can lead to many difficulties.

Similarly, the facilities based on the old principle of bacteria beds very safe and very stable have the disadvantage of requiring large and unsightly works an important load loss.

The present invention LUTs these drawbacks by proposing a installâtion purification, more particularly for use in cleaning up water rejected by small communities, or by small industries, which is both simple and safe and at the same time does not require a large manufacturing cost and high capital expenditures in hand a-d¹ work.

This installation is based on the principle of the spinning reels which combine some of the advantages of activated sludge processes (high cleaning efficiency) and bacteria beds (reduced power consumption). The rotating drum is made of a filler material having a large developed surface per unit volume to promote economical transfer of atmospheric oxygen on the liquid film. The passage in the aeration tank, the aerated liquid is intimately mixed with the activated sludge in suspension * to increase the mass biological activated sludge is entrained towards the secondary settler is retrieved and returned to the aeration tank.

WITH for this purpose, the invention relates to a system comprising devices for providing mechanical and biological treatment of waste water, characterized in that the devices are aligned on a common driving axis of TiN * controlled by single motor.

This arrangement enables to produce a plant with extreme simplicity of operation, since only one drive unit allows control of all treatments to be undergone by the water to be purified.

According to another feature of the invention, the devices for providing 1' mechanical purification of water are a raking device and apparatus for degreasing *

This cleaning prior physical reduces the servicing of the equipment, since the grease and décîtets of large volume will be eliminated at the beginning of the operation.

Çelen another feature of the invention, the devices for providing the biological purification of wastewater are constituted by an aeration tank and one or more spinning reels driven by the main shaft which is partially immersed in the tank.

To obtain a high transfer of oxygen in

activated sludge, the developed surface of the materials forming the rotating drum must be very large. In effect, the inner and outer surface of these drums absorbs, in water, the organic matter in solution, and then assures their oxygenation in the air, thereby effecting the desired biological purification.

Pipeline according to another feature of the invention, the drive shaft is inclined relative to the horizontal.

This inclination may be, for example, of 5° about relative to the horizontal. Its interest is both improve the filling members forming the spinning reels in the biological portion of the processing and also allow easier application of the various elements. It is interesting that the position of the axis is relatively remote from the water to facilitate screening and degreasing, while immersing the rotating drum must be sufficient to ensure good transfer of activated sludge.

According to another feature of the invention, the device includes a lead frame raking curve through which water is admitted and a scraper arm fixed to the main shaft which drives the solid waste to a solid waste repository.

This arrangement provides for a substantial improvement with respect to small scale purification apparatuses currently in use, wherein the raking is indispensable, since the coarse, as described various, papers, peelings, andc... nay disturbing following treatment, and is typically implemented roughly by manual removal of debris with a rake on a fixed grid or through a grid-shaped basket.

According to another feature of the invention, the degreasing device consists of a vane fixed on the main axis that scum on the surface of a tank containing water to be purified to drop down the floating wastes in a container specially designed for the purpose.

Oils, fats, domestic and hydrocarbons VCO tendency has. forming packs floating detrimental to the purification. XI is therefore important to avoid them "

According to another feature of the invention, the plant comprises means for regulating and homogenize the arrival rate of wastewater in the aeration tank.

Variations compositions and flow rate which are even more important communities are reduced, decrease the effectiveness of the treatment biologically and decantation. For subsequent disadvantages to these changes, a constant rate sampling device is attached to the main axis. It consists of a spoon which takes, at each turn, a constant flow rate regardless of the level of the water accumulated in the compartment. In this way, when the tailings are large in volume, the tank will rempllit; it is emptied then gradually when the supply of the off is more reduced. The volume collected by the spoon is then transferred to each tower to the biological treatment tank. The shape this spoon is provided such that there is little deposition.

According to another feature of the invention, the walls of the buffer vessel are inclined to - 5®60° relative to vertical.

Thus, the sludge which form descend toward the bottom.

According to another feature of the invention, the drum is packed with honeycomb elements for increasing the developed surface on which bind the microorganisms.

The inclination of the axis drive allows the filling and emptying more regular honeycomb elements at each revolution.

According to another feature of 1' a, the plane of the drum is not perpendicular to the axis of rotation.

L¹ inclination adopted causes a helical movement which is reversed in each half-turn rotation. This provides an agitation of the liquid contained in the vessel, which opposes the deposition of activated sludge. Further, the circulation resulting in the honeycomb elements prevents their clogging by the bacterial film which tends to form. It is thus possible to act separately on the tangential speed (rotational speed) and on the longitudinal movement (inclination about the drum axis).

According to another feature of the invention, the installation comprises a clarifier tank equipped at its periphery with a weir for taking the waters are first of suspended matter.

According to another feature of the invention, the plant comprises means for recycling sludge deposited in the bottom of the settling vessel to the aeration tank.

The recycling sludge deposited in the bottom of the clarifier tank towards the aeration vessel consists of a tube extending from the bottom of the settling vessel to a recycling chamber located at liquid tub and inside which a spoon comes regularly taking a constant volume. This spoon, attached to the principal axis, returns the sludge to the aeration tank.

On biological treatment plants, it is necessary periodically discharging the excess sludge thus. This adjustment is particularly difficult, because pollution is variable over time, and an excess sludge causes deterioration thereof by anaerobic fermentation or denitrification while a failure is not able to provide a proper cleaning.

The evacuating means provided consist of a tube down to a determined level of the clarifying tank (following adjustment pollution received and the purification performance of desired). This tube is connected to an exhaust chamber positioned on the surface of the clarifier tank. A spoon connected on the main axis periodically immersed in the discharge chamber. When the amount of the sludge is very large, is removed, in this manner, a uniform flow, but when the amount of the sludge is very low (less pollution or extraction too high), the sampling tube does not reach the sludge level and only discharges more than water. Thus biological mass does not decrease overly.

The installation which is the object of the present invention will be described in more detail, with the aid of the accompanying drawings, in which:

figure 1 - line is plan view of the installation showing the different devices that compose this installation;

figure 2 - is a overview of the installation;

figure 3 - is a cross-section along the axis of a variant of this plant made by assembly of several vessels the j

figure 4 - is a sectional view of the aeration tank.

According to Figures 1 to 3_F. the untreated water arrive in 1¹ - nuclall circuitcreating method according to the arrow centeredly processes undergo a physical screenings and degreasing in tanks 1 and 2. Then, the untreated water that has been freed of dirt and fats that float gravity flow to a buffer tank 3 where they accumulate before being sent in aeration tank 4 in a manner which will be described in more detail below.

In the aeration tank 4, contaminated water to undergo the biological treatment. This treatment is a rotating drum 5 which is partially immersed in the liquid contained in the vessel 4, and whose periphery is made of honeycomb elements 6 which have the objective of increasing the developed surface of the drum 5 in. contact with oxygen in air, when located above the water level or with the waste water. Gold, it is precisely this contact of contaminated water with air, by rotation of the drum, which allows biological degradation reactions for water purification.

After biological treatment, the effluent passes

by gravity in a clarifier tank 7 where the suspended substances are physically settled.

The walls 30 and 70 vessels buffer and clarification are inclined to 60° 50 c in vertical to allow the sludge to descend to the bottom of these vessels.

The different processing devices are plaoés keel-next to each other on a single drive shaft 8 controlled by a single motor 9 and inclined at an angle θ (relative to the horizontal, to allow better flow of liquids to be purified.

Of raking in the tub, the water to be purified is passed through a filter grid curve 10 through which water is admitted, thereby removing the d * gross debris in addition, a comb 11 fixed on the main axis 8 is adapted to scrape the surface of the water to drive the solid waste to a tray 12.

Further, on the axis 8 and above the vessel lubricating de=2, there is provided a pallet 13 which scum on the surface of the vessel 2, to remove oils, derived fats OD " mestic, or hydrocarbons that have floated to the surface, and drop them into a waste receptacle 114.

After being freed and greases and de -=duties in the coarsest, water to be purified is fed into the.

buffer vessel 3 "above which a spoon 14 is f ±=xée to the rotation axis 8, and retrieves, for each revolution of the shaft, a constant flow of water to be purified irrespective of the level of the water accumulated in the tank 3" then, when the spoon is full at the next revolution, it rejects the water therein with its end 140, in the aeration tank 4. This arrangement provides a constant flow rate into the aeration tank 4, while allowing the water to be purified from accumulating in said buffer vessel 3 when its flow rate is important.

In this way, when the tailings are important, the volume of the buffer tank 3 is filled; it is emptied, then, gradually, when the supply of the off is more reduced.

The inclination of the axis of rotation 8, with respect to the horizontal, ensures a more even filling and discharge honeycomb elements 6 at every turn. Further, the inclination of the tambour5par ratio to the rotation axis 8 provides the intermixing of the contents of the aeration tank 4 and forces the liquid through the honeycomb elements 6. In effect, it is important that the activated sludge are maintained in suspension and that they do not settle unduly on the bottom of the tank and on the walls of the honeycomb body.

According to Figure 4, the inclination of the plane of the drum with respect to the axis of rotation can be adjusted by means of manual or automatic adjustment for changing the magnitude of the helical movement. In this way, with a fixed rotational rate, it is possible to obtain: has) an oxygen transfer, and b) a stirring intensity, and c) a flow rate through the honeycomb elements, most had least imîènis - 6s_T-

According to Figure 3, the clarifying tank 7 has, at its periphery, a weir 15 for taking the waters are first of suspended matter flowing through pipe 15, 0.

It is possible to recycle the settled sludge in the bottom 16 of the clarifier tank, using a pipe 160 which opens into a recycle chamber 17" located at liquid of the clarifier, and within which a spoon 18, attached to the shaft 8, draws a constant volume of water, for recycling into the vessel through the hollow axle.

According to Figure 1, the installation comprises a discharge chamber 19 receiving the excess sludge from a tube 20 down to a determined level of the clarifying tank 7 and provided with a spoon 21, connected on the axis 8 which dips periodically in the chamber 19 for discharging, when the amount of the sludge. is very large, consistent flow of sludge outwardly, but, when the volume of sludge is very low (less pollution), the sampling tube does not reach the sludge level and only discharges more than water, and biological mass dimine does not unduly.

The measures indicative above can be used all together or in part. The assembly can be implemented with a number of modular elements, used side by side in order to reduce the price of optional prefabrication and transportation.