Search

EP-3720821-B1 - METHOD AND DEVICE FOR BIOLOGICAL WASTE WATER PURIFICATION

EP3720821B1EP 3720821 B1EP3720821 B1EP 3720821B1EP-3720821-B1

Inventors

  • INGERLE, KURT

Dates

Publication Date
20260506
Application Date
20181001

Claims (18)

  1. A method for carrying out biological purification of wastewater with the aid of activated sludge in a sewage treatment plant, which method allows for an emergency operation of the sewage treatment plant, wherein in said emergency operation one or more tanks of the sewage treatment plant are shut down or emptied to allow for e.g. repair or maintenance work, wherein the sewage treatment plant comprises: • an activated sludge tank that can be ventilated (hereinafter referred to as the B tank), • at least two sedimentation and recirculation tanks (hereinafter referred to as SU tanks), wherein the at least two SU tanks include at least one first sedimentation and recirculation tank (hereinafter referred to as SU 1 tank) and at least one second sedimentation and recirculation tank (hereinafter referred to as SU 2 tank), wherein the at least one SU 1 tank and the at least one SU 2 tank are continuously connected hydraulically to the B tank, wherein in the at least one SU 1 tank and in the at least one SU 2 tank a number of operating cycles are carried out over the course of a day, including a sludge return phase, a recirculation phase, a pre-sedimentation phase and a draw-off phase (hereinafter referred to as the S phase, U phase, V phase, and A phase, respectively), and • a tank for biological phosphor elimination (hereinafter referred to as P tank), wherein the P tank is hydraulically connected with the B tank via one or more openings, and wherein the volume of the P tank is mixed permanently or intermittently, wherein in said method the wastewater is first introduced into the P tank and subsequently into the B tank, and then from the B tank, in alternation, into the at least one SU 1 tank and into the at least one SU 2 tank, wherein consecutively, in the S phase at least part of the thickened activated sludge is introduced from the at least one SU 1 tank and the at least one SU 2 tank, respectively, into the P tank, in the U phase the thickened activated sludge is again mixed with the water, in the V phase the activated sludge is sedimented, and in the A phase treated water is drawn off by opening an effluent device of the respective SU tank, wherein in the at least one SU 1 tank and the at least one SU 2 tank said operating cycles are phase-shifted in relation to one another, the A phases in the at least one SU 1 tank and the at least one SU 2 tank border one another, a flow passes through the at least one SU 1 tank and the at least one SU 2 tank, respectively, merely in the A phases, an approximately constant water level is provided and therefore a wastewater treatment system discharge corresponding to the wastewater treatment system supply develops ("continuous flow" principle), characterized in that the B tank is divided into two tanks B 1 and B 2 (hereinafter referred to as B 1 tank and B 2 tank) which are hydraulically connectable via the P tank, wherein the B 1 tank is continuously connected hydraulically to at least one SU tank and the B 2 tank is continuously connected hydraulically to at least one SU tank, in order to build up a one-line sewage treatment plant, wherein the P tank comprises closure means to cut off the hydraulic connection between the P tank and the B 1 tank and/or the B 2 tank, and wherein each of the SU tanks comprises an overflow unit for draining excess treated wastewater in the sewage treatment plant, wherein in the emergency operation the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off, wherein in the S phase, the U phase and the first half of the V phase, the waste water is then accumulated and lifted up in the tanks that are not cut off, the sludge settles in the respective SU tank(s), and the excess treated wastewater without the sludge can effluent via the overflow unit of the respective SU tank(s) and a maximum height of the water level in the tanks is not exceeded, and, wherein in the A-phase, when treated water is drawn off by opening the effluent device of the respective SU tank(s), the water level assumes a lower level.
  2. The method according to claim 1, characterized in that : the P tank is positioned in the middle of the B tank and adjacent to the at least two SU tanks, and the P tank divides the B tank into the B 1 tank and the B 2 tank, wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s); or characterized in that : the B tank is located between the P tank and the SU tanks, the B tank is divided into the B 1 tank and the B 2 tank by a wall, wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening, wherein, in the S phase, the thickened activated sludge is transferred via one or more pipes from the at least one SU 1 tank and the at least one SU 2 tank, respectively, into the P tank, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s).
  3. The method according to claim 2, wherein the B 1 tank is continuously connected hydraulically to one SU 1 tank and wherein the B 2 tank is continuously connected hydraulically to one SU 2 tank, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s), in order to shut down either both the B 1 tank and SU 1 tank or both the B 2 tank and SU 2 tank, and the waste water is then accumulated and lifted up in the tanks that are not shut down, and the treated wastewater can effluent via the overflow unit of the respective SU tank that is not shut down.
  4. The method according to claim 1, characterized in that the P tank is positioned in the middle of the B tank and divides the B tank into the B 1 tank and the B 2 tank, wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening, wherein the B 1 tank is positioned between the P tank and at least one SU tank and wherein the B 2 tank is positioned between the P tank and at least one SU tank, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s).
  5. The method according to claim 4, characterized in that : the B 1 tank is continuously connected hydraulically to one SU 1 tank, and the B 2 tank is continuously connected hydraulically to one SU 2 tank, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s), in order to shut down either both the B 1 tank and SU 1 tank or both the B 2 tank and SU 2 tank, and the waste water is then accumulated and lifted up in the tanks that are not shut down, and the treated wastewater can effluent via the overflow unit of the respective SU tank that is not shut down; or characterized in that : the B 1 tank is continuously connected hydraulically to one SU 1 tank and one SU 2 tank (hereinafter referred to as "tanks B 1 -SU 1 -SU 2 "), and the B 2 tank is continuously connected hydraulically to one SU 1 tank and one SU 2 tank (hereinafter referred to as "tanks B 2 -SU 1 -SU 2 "), wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s), which leads to a shut-down of either tanks B 1 -SU 1 -SU 2 or tanks B 2 -SU 1 -SU 2 , and the waste water is then accumulated and lifted up in the tanks that are not shut down, and the treated wastewater level can ascent up to the upper edge of the overflow unit of the respective SU tanks that are not shut down.
  6. The method according claim 1, characterized in that the B tank is located between the P tank and the SU tanks, the B tank is divided into the B 1 tank and the B 2 tank by a wall, wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening, wherein, in the S phase, the thickened activated sludge is transferred via one or more pipes from the at least one SU 1 tank and the at least one SU 2 tank, respectively, into the P tank, wherein in said method, in the event of an emergency, the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank is cut off by closing the respective closable opening(s), wherein, during the full operation phase, in the S-phase, the thickened activated sludge is largely channeled into the B 1 tank and the B 2 tank, respectively and the P tank primarily has the task to divide the incoming wastewater to B1 and B 2 .
  7. The method according to any one of claims 1 to 6, characterized in that the P tank is aerated and, optionally, also the B 1 tank and the B 2 tank.
  8. The method according any one of claims 1 to 7, characterized in that the P tank comprises aeration and/or stirring units that are removable for repairs.
  9. The method according to any one of claims 1 to 8, characterized in that the tanks that are cut off in the event of emergency, are emptied for a short time, e.g. for repair, while at the same time the biological purification of wastewater is operated with the tanks that are not shut down.
  10. The method according to claim 7, characterized in that the P tank comprises aeration units or aeration units and stirring units, wherein: in full operation of all tanks the aeration in the P tank is activated and a biological phosphorus elimination is dispensed with; or wherein: in full operation of all tanks the aeration in the P tank is switched off and the biological phosphorus elimination goes into operation.
  11. The method according to any one of claims 1 to 10, characterized in that , in the event of an emergency, an agent for enhancing sludge sedimentation, preferably a flocculant, is added to one or more of the tanks that are not cut off.
  12. The method according to any one of claims 1 to 11, characterized in that , in the event of an emergency, the excess sludge is removed from the SU tank(s) that is/are not cut off.
  13. A sewage treatment plant for carrying out biological purification of wastewater with the aid of activated sludge (4), wherein the sewage treatment plant is configured to allow for operating in an emergency operation, wherein in said emergency operation one or more tanks of the sewage treatment plant are shut down or emptied to allow for e.g. repair or maintenance work, wherein the sewage treatment plant comprises: • an activated sludge tank that can be ventilated (hereinafter referred to as the B tank), • at least two sedimentation and recirculation tanks (hereinafter referred to as SU tanks), wherein the at least two SU tanks include at least one first sedimentation and recirculation tank (hereinafter referred to as SU 1 tank) and at least one second sedimentation and recirculation tank (hereinafter referred to as SU 2 tank), wherein the at least one SU 1 tank and the at least one SU 2 tank are continuously connected hydraulically to the B tank, wherein the at least one SU 1 tank and the at least one SU 2 tank are configured to carry out a number of operating cycles over the course of a day, including a sludge return phase, a recirculation phase, a pre-sedimentation phase and a draw-off phase (hereinafter referred to as the S phase, U phase, V phase, and A phase, respectively), wherein each of the SU tanks comprises an effluent device (10) configured to be opened during the A phase, and • a tank for biological phosphor elimination (hereinafter referred to as P tank), wherein the P tank is hydraulically connected with the B tank via one or more openings (2), and wherein the volume of the P tank is mixed permanently or intermittently, wherein the sewage treatment plant is configured to first introduce the wastewater into the P tank and subsequently into the B tank, and then from the B tank, in alternation, into the at least one SU 1 tank and into the at least one SU 2 tank, wherein the sewage treatment plant is configured to consecutively, in the S phase introduce at least part of the thickened activated sludge from the at least one SU 1 tank and the at least one SU 2 tank, respectively, into the P tank, in the U phase mix the thickened activated sludge again with the water, in the V phase have the activated sludge sedimented, and in the A phase draw off treated water by opening an effluent device of the respective SU tank, wherein in the at least one SU 1 tank and the at least one SU 2 tank said operating cycles are phase-shifted in relation to one another, the A phases in the at least one SU 1 tank and the at least one SU 2 tank border one another, a flow passes through the at least one SU 1 tank and the at least one SU 2 tank, respectively, merely in the A phases, an approximately constant water level is provided and therefore a wastewater treatment system discharge corresponding to the wastewater treatment system supply develops ("continuous flow" principle), characterized in that the B tank is divided into two tanks B 1 and B 2 (hereinafter referred to as B 1 tank and B 2 tank) which are hydraulically connectable via the P tank, wherein the B 1 tank is continuously connected hydraulically to at least one SU tank and the B 2 tank is continuously connected hydraulically to at least one SU tank, in order to build up a one-line sewage treatment plant, wherein the P tank comprises closure means to cut off the hydraulic connection between the P tank and the B 1 tank and/or the B 2 tank; wherein, when the sewage treatment plant operates in the emergency operation, the closure means are configured to cut off the hydraulic connection between the P tank and either the B 1 tank or the B 2 tank, and wherein each of the SU tanks comprises an overflow unit (3) which is configured to drain excess treated wastewater without the sludge in the sewage treatment plant in said emergency operation, wherein, in the S phase, the U phase and the first half of the V phase, the waste water rises in the tanks that are not cut off, and a maximum height of the water level (8) in the tanks is not exceeded, and wherein in said emergency operation, the effluent device (10) of the respective SU tank is configured to be opened during the A phase, whereby the water level assumes a lower level.
  14. The sewage treatment plant according to claim 13, characterized in that : the P tank is positioned in the middle of the B tank and adjacent to the at least two SU tanks, and the P tank divides the B tank into the B 1 tank and the B 2 tank, wherein each of the B 1 tank and the B 2 tank are hydraulically connectable with the P tank via at least one closable opening (2); or characterized in that : the B tank is located between the P tank and the SU tanks, the B tank is divided into the B 1 tank and the B 2 tank by a wall (11), wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening, wherein each SU tank is connected with one or more pipes (12) which pipes are adapted to transfer the thickened activated sludge (4) from the respective SU tank into the P tank.
  15. The sewage treatment plant according to claim 14, characterized in that the B 1 tank is continuously connected hydraulically to one SU 1 tank and wherein the B 2 tank is continuously connected hydraulically to one SU 2 tank.
  16. The sewage treatment plant according to claim 13, characterized in that the P tank is positioned in the middle of the B tank and divides the B tank into the B 1 tank and the B 2 tank, wherein each of the B 1 tank and the B 2 tank is hydraulically connectable with the P tank via at least one closable opening (2), wherein the B 1 tank is positioned between the P tank and at least one SU tank and wherein the B 2 tank is positioned between the P tank and at least one SU tank.
  17. The sewage treatment plant according to claim 16, characterized in that the B 1 tank is continuously connected hydraulically to one SU 1 tank, and the B 2 tank is continuously connected hydraulically to one SU 2 tank; or in that the B 1 tank is continuously connected hydraulically to one SU 1 tank and one SU 2 tank (hereinafter referred to as "tanks B 1 -SU 1 -SU 2 "), and the B 2 tank is continuously connected hydraulically to one SU 1 tank and one SU 2 tank (hereinafter referred to as "tanks B 2 -SU 1 -SU 2 ").
  18. The sewage treatment plant according any one of claims 13 to 17, characterized in that the P tank is constructed in form of a circulation tank.

Description

The present invention relates to a method for carrying out biological purification of wastewater with the aid of activated sludge in a sewage treatment plant, which method allows for an emergency operation of the sewage treatment plant, the sewage treatment plant comprising: an activated sludge tank that can be ventilated (hereinafter referred to as the B tank),at least two sedimentation and recirculation tanks (hereinafter referred to as SU tanks), wherein the at least two SU tanks include at least one first sedimentation and recirculation tank (hereinafter referred to as SU1 tank) and at least one second sedimentation and recirculation tank (hereinafter referred to as SU2 tank), wherein the at least one SU1 tank and the at least one SU2 tank are continuously connected hydraulically to the B tank, wherein in the at least one SU1 tank and in the at least SU2 tank a number of operating cycles are carried out over the course of a day, including a sludge return phase, a recirculation phase, a pre-sedimentation phase and a draw-off phase (hereinafter referred to as the S phase, U phase, V phase, and A phase, respectively), anda tank for biological phosphor elimination (hereinafter referred to as P tank), wherein the P tank is hydraulically connected with the B tank via one or more openings, and wherein the volume of the P tank is mixed permanently or intermittently, wherein in said method the wastewater is first introduced into the P tank and subsequently into the B tank, and then from the B tank, in alternation, into the at least one SU1 tank and into the at least one the SU2 tank,wherein consecutively, in the S phase at least part of the thickened activated sludge is introduced from the at least one SU1 tank and the at least one SU2 tank, respectively, into the P tank, in the U phase the activated sludge is again mixed with the water, in the V phase the activated sludge is sedimented, and in the A phase treated water is drawn off, wherein in the at least one SU1 tank and the at least one SU2 tank said operating cycles are phase-shifted in relation to one another, the A phases in the at least one SU1 tank and the at least one SU2 tank border one another, a flow passes through the at least one SU1 tank and the at least one SU2 tank, respectively, merely in the A phases, an approximately constant water level is provided and therefore a wastewater treatment system discharge corresponding to the wastewater treatment system supply develops ("continuous flow" principle). The present inventions also relates to a sewage treatment plant for carrying out biological purification of wastewater with the aid of activated sludge, which sewage treatment plant is suitable for carrying out the method of the present invention, wherein the sewage treatment plant comprises: an activated sludge tank that can be ventilated (hereinafter referred to as the B tank),at least two sedimentation and recirculation tanks (hereinafter referred to as SU tanks), wherein the at least two SU tanks include at least one first sedimentation and recirculation tank (hereinafter referred to as SU1 tank) and at least one second sedimentation and recirculation tank (hereinafter referred to as SU2 tank), wherein the at least one SU1 tank and the at least one SU2 tank are continuously connected hydraulically to the B tank, wherein in the at least one SU1 tank and in the at least SU2 tank a number of operating cycles are carried out over the course of a day, including a sludge return phase, a recirculation phase, a pre-sedimentation phase and a draw-off phase (hereinafter referred to as the S phase, U phase, V phase, and A phase, respectively), anda tank for biological phosphor elimination (hereinafter referred to as P tank), wherein the P tank is hydraulically connected with the B tank via one or more openings, and wherein the volume of the P tank is mixed permanently or intermittently. Methods and sewage treatment plants for carrying out biological purification of wastewater with the aid of activated sludge were previously described in WO 01/46075 A2. The methods and treatment plants described in WO 01/46075 A2 are known under the registered trademark BIOCOS, wherein more than 150 plants have been implemented so far. Methods and sewage treatment plants for carrying out biological purification of wastewater with the aid of activated sludge which, in addition, comprise a P tank for biological phosphor elimination are known from WO 2016/154646 A1. WO 2016/154646 A1 discloses a method for biological wastewater purification with phosphorous removal by means of a sewage treatment plant comprising an activated sludge tank, sedimentation and recirculation tanks and a tank for biological phosphorous removal. US 5 902 484 A describes a biological process and a system for treating wastewater based on a sequencing batch reactor (SBR) process with constant water level. CN 202 369 444 U discloses a multi-mode constant water level sequencing batch reactor (SBR) system f