Patent EP-2284128-A2 (EP)
Inventor: BOLLER REINHARD
IPC: C02F1/34
Filed: 2010-07-08
Abstract: The method and apparatus for purifying wastewater in small sewage treatment plants, comprises a treatment zone for mechanical precleaning and sludge storage, a biological purification zone, a separating device (7), from which the purified wastewater is conveyed in short time intervals using a conveying pump, incorporated into the biological purification zone, and a device conveying the surplus sludge from the biological purification zone into the mechanical treatment zone. The mechanical treatment zone and the biological purification zone are connected with one another by an opening. The method and apparatus for purifying wastewater in small sewage treatment plants, comprises a treatment zone for mechanical precleaning and sludge storage, a biological purification zone, a separating device (7), from which the purified wastewater is conveyed in short time intervals using a conveying pump, incorporated into the biological purification zone, and a device conveying the surplus sludge from the biological purification zone into the mechanical treatment zone. The mechanical treatment zone and the biological purification zone are connected with one another by an opening. The activated sludge settled itself inside the separating device again drops from the downwardly opened separating device into the biological purification zone. The small sewage treatment plant comprises several containers. The connection between the mechanical treatment zone and the biological purification zone is produced over a connecting line or conveying pump. The separating device is measured, so that the required settling process of the activated sludge occurs during the residence time of the wastewater in the separating device. The interval between the two conveying processes is to be stopped in connection with the parameters of the separating device, so that the required dwell time of the wastewater in the separating device is allowed and the wastewater in the plant flowing between the two conveying processes of the plant is stored by a slight increase of the water level. The plant consists of one container with two chambers in the arrangement of the process and the apparatus or the plant consists of two containers with one chamber. The connection between the both required treatment zones are produced over openings (10) or pipelines for a free passage. In an alternative execution, the loading of the biological purification zone is produced over the conveying device. The conveying device is switched in corresponding time intervals, which are in a correlation with the quantity of the purified wastewater required from the plant. The mechanical treatment zone and the biological purification zone consist of chambers, containers or container parts. The method takes place in both new plants and existing plants. The time period between the two conveying processes for the clear water discharge is less than in sequencing batch reactor (SBR) systems, where the time period is 20-60 minutes. The time period between the two conveying processes is fixedly set in control, is variably formed or is automatically changed by measuring devices. The measuring device controls the aerating times and the times for the surplus sludge discharge. A break switch is to be activated at the control by an operator and reduces the aerating times, which are extend the time periods between the two clear water discharges and run the conveying pump for the surplus sludge longer for carbon mobilization to fed the nutrients in the biological zone by the developed rotational movement between the both treatment zones. The separating device has circular, rectangular, quadratic or geometrical construction form. The bottom area of the separating device is opened in the arrangement and is provided with a bevel or formation, which ensures that the activated sludge settled in the separating device again reaches into a biological reactor. The conveying pump for the surplus sludge discharge is fixed in the separating device or fixed in the container, and is adjustably implemented in height and position. The conveying pump for the clear water discharge is fixed or arranged inside or outside of the separating device, and is adjustably implemented in height and position. The number, type, material and arrangement of the separating device are varied. The separating device consists of one chamber or a part of the chamber of the container separated by a simple installation of plate made of plastic or other material. The method and the apparatus are simply adapted by number, dimensions, parameters and arrangement of the separating device in relation to the number of containers, chamber distribution and wastewater flow in connection with the interpretation of the conveying device for the clear water discharge and the conveying intervals. The method and the apparatus are used and/or retrofitted in all sequencing batch reactor (SBR) systems present in the market or other small sewage treatment plant systems. A floater or a height level measurement unit detects the water level in the mechanical precleaning or in the biological purification zone. The small sewage treatment plants report to the control, so that the corresponding aerating times and the conveying times are automatically adapted to the conveying pump. A compressed air lifter (8) for the clear water discharge and the surplus water discharge is fixed to the separating device. The operation of the conveying pumps provides in addition to the simple installation of the system by the corresponding vibrations, so that the settling process of the activated sludge is conveyed in an optimized manner. The compressed air lifter and immersion pumps or warning devices are used for the conveyance of the purified wastewater and surplus sludge and for the optional loading of the biological zone. The conveying pump for the surplus sludge discharge is simultaneously used for a recirculation for the purpose of denitrification and/or for the carbon mobilization for comparing loading and unloading of underload operations.