MINI SEWAGE TREATMENT PLANT AND USE OF THE PLANT

Abstract: A mini sewage treatment plant for building into an existing septic tank and of the kind consisting of a vessel which is divided into a first processing chamber, a sedimentation chanber with inclined bottom and separation plates together with sludge outlet at the lower end part of the chamber, and a discharge for effluent at the upper end of the vessel, the three chambers being connected by overflows, where the basic outline of the vessel is triangular, and at each corner there is placed a pipe for accommodating means for pumping and aeration of sewage (A), for level control (B) and for dewatering sludge (C), respectively, where the first and the second pipe (A and B) are disposed in the first processing chamber, and the third pipe (C) is disposed in the same corner as the discharge chamber and constitute the sludge outlet of the sedimentation chamber in the lower end part of the chamber.

Description: MINI SEWAGE TREATMENT PLANT AND USE OF THE PLANT The present invention concerns a mini sewage treatment plant for sewage and intended for building into an existing septic tank and of the kind consisting of a vessel which is divided into a first processing chamber, a sedimentation chamber with inclined bottom and separation plates together with sludge outlet at the lower end part of the chamber, and a discharge chamber for effluent at the upper end of the vessel, the three chambers being connected by overflows. Field of Application of the Invention Mini sewage treatment plants are to be used at estates in open country where it is not possible to connect to the public sewer network. State of the Art Plants, which are poured in concrete or moulded in glass fibre and requiring construe - tion works, are known. Furthermore, from GB 2,050,338 A is known a plant of the kind mentioned in the introduction for treating sewage. This plant consists of a vessel divided into three chamber which are connected by overflows. The sewage runs into a first processing chamber and further over into a sedimentation chamber having inclined bottom and separation plates. The sedimentation chamber has a sludge outlet at the lower end part of the chamber. Furthermore, there is provided a discharge channel for effluent at the upper end of the vessel. The known plant is built compactly and may be installed at places where only a limited space is available, e.g. in a container. However, the shape and size of the plant does not make it suitable for building into existing drainage pits, as for example septic tanks. The object of the present invention is to indicate a plant of the kind mentioned in the introduction, and which is suitable for use at estates where it is not possible or desirable to connect to the public sewer network. The New Technique According to the present invention this is achieved with a plant of the type indicated in the introduction, which is peculiar in that the basic outline of the vessel is triangular, and that at each corner there is placed a pipe for accommodating means for pumping and aeration of sewage, for level control and for dewatering sludge, respectively, where the first and the second pipe are disposed in the first processing chamber, and the third pipe is disposed in the same corner as the discharge chamber and constitutes the sludge outlet of the sedimentation chamber in the lower end part of the chamber. On the background of the triangular shape and the size of the plant, it is suitable for building into an existing septic tank. Hereby construction works are avoided. It is thus possible to achieve a lesser environmental impact from the single estates using the plant. The triangular vessel of the plant is provided with separation plates. Sewage, which by a traditional inlet has been conducted to the septic tank, is pumped around in a pipe loop by means of a pump while aeration of the sewage takes place simultaneously. The aeration is performed by means which are situated in the pipe used for pumping the sewage from the septic tank to the vessel. Then the sewage is recirculated in the first chamber and back to the septic tank until the level control in the second pipe closes the outlet from the first chamber to the septic tank. Thus a continual aeration occurs. When the level control in the second pipe closes the outlet in the first chamber, the liquid level will rise, and the sewage runs over into the separation chamber. Here the sludge is settled and ends up in a safe way in the lower end part at the third corner. Because of the tapered shape, all the sludge will be collected in the corner where a sludge pump is disposed. From here the sludge is thus conducted by means of the sludge pump to a separate tank. This may be placed in the septic tank or outside the septic tank. The effluent runs from the clearing and settling vessel to the discharge pipe from which it is conducted further to recipient or to a cesspool system. The plant is preferably made of stainless steel and consists of four parts. These parts may be assembled at the site of mounting. The invention will be explained more closely below with reference to the accompany- ing schematic drawing, where: Fig. 1 shows a plane view of the plant from above. Fig. 1A shows a partial side view, partly in section, of a vessel forming a part of the plant according to the invention, Fig. 2 shows a partial view for illustrating a pumping pump and aeration pipe, Fig. 3 shows a side view of a level control, Fig. 4 shows a side view, partly in section, of a dewatering system, and Fig. 5 shows a view for illustrating the plant placed in a septic tank. Fig. 1A shows a clearing and settling vessel made in triangular shape with inclined bottom which is deepest at the pointed end from which the sludge is taken. The vessel is provided with separation plates dividing it into three compartments and inclined separation plates for sludge separation. In compartment 1 the sewage is recirculated, and when the level rises in the tank, the outlet closes more and more whereby the level rises in the compartment, and the sewage runs over to compartment 2 which is the settling vessel. Here the sludge settles and is conducted to a tank which is placed in the septic tank. The cleared water runs into compartment 3 and from there to cesspool or recipient. Fig. 2 shows a pipe with pump and an aeration pipe. This part is delivered in varying lengths and is mounted after Fig. 1 A has been fitted in the septic tank. Fig. 3 shows the level control which is standard. It consists of a pipe, a flap and a float which may be adjusted in height according to the desired level. This part is also mounted on site. Fig. 4 shows a dewatering system for pressing some of the water out of the sludge. It consists of an air cylinder, a pump cylinder, and a back pressure valve together with an aeration hole. This part is also standard and is mounted on site. Fig. 1 and 5 shows the plant placed in a well.

Claims: CLAIMS 1. A mini sewage treatment plant for building into an existing septic tank and of the kind consisting of a vessel which is divided into a first processing chamber, a sedi- mentation chamber with inclined bottom and separation plates together with sludge outlet at the lower end part of the chamber, and a discharge chamber for effluent at the upper end of the vessel, the three chambers being connected by overflows, characterised in that the basic outline of the vessel is triangular, and that at each comer there is placed a pipe for accommodating means for pumping and aeration of sewage (A), for level control (B) and for dewatering sludge (C), respectively, where the first and the second pipe (A and B) are disposed in the first processing chamber, and the third pipe (C) is disposed in the same corner as the discharge chamber and constitute the sludge outlet of the sedimentation chamber in the lower end part of the chamber. 2. A sewage treatment plant according to claim 1, characterised in that the means for aerating the sewage is an aerating pipe disposed centrally in the pipe for pumping the sewage. 3. A sewage treatment plant according to claim 1 or 2. characterised in that the level control comprises a flap connected to an air cylinder which is controlled by a timer. 4. A sewage treatment plant according to any preceding claim, characterised in that the means for sludge dewatering comprises an air cylinder, an pump cylinder and a back pressure valve together with an aerating hole, and at the last part of the return stroke, the hole will be closed by the piston, and the water over the piston will be pressed through the filter and thereby clean it. 5. A sewage treatment plant according to any preceding claim, characterised in that it is made of stainless steel. which is disposed in a septic tank.

Inventors: LUDVIGSEN HENNING, LUDVIGSEN, HENNING
Applicants: LUDVIGSEN HENNING, LUDVIGSEN, HENNING
Application year: 2000
Main classification: B01D21
IPC codes: C02F3, E03F11