Method of controlling a circulation-type wastewater treatment plant via a stored parameter relationship in a control unit

Patent metadata

Field	Value
Publication number	US-10273173-B2
Application number	US-201515318444-A
Country	US
Kind code	B2
Filing date	Jun 15, 2015
Priority date	Jun 17, 2014
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A plant and method for controlling such a plant suitable for treatment of waste water. The plant includes a basin, a flow generating machine adapted to generate a liquid flow in the basin, equipment in the basin that effects the momentum of the liquid flow, and a control unit. The method includes the steps of: storing a predetermined relationship between the operational speed N of the flow generating machine and an operational parameter P from which the torque M of the flow generating machine may be derived, determining the operational speed N, determining a set value of the operational parameter P of the flow generating machine, determining a real value of the operational parameter P of the flow generating machine, and adjusting the operational speed N if the real value of the operational parameter P is different than the set value of the operational parameter P.

First claim

The invention claimed is:

1. A method for controlling a plant for treatment of waste water, wherein the plant comprises:
a basin constituted by a circulation channel and configured to contain waste water,
at least one flow generating machine constituted by a submerged mixer machine that is arranged in the basin and configured to generate a liquid flow in the basin,
equipment arranged in the basin and that effects a momentum of the waste water flowing along the circulation channel, wherein an operational speed N of the flow generating machine is (i) higher than a predetermined lowest allowable operational speed Nmin to prevent solid matter from accumulating on a bottom of the basin, and (ii) lower than a predetermined highest allowable operational speed Nmax to prevent the flow generating machine from becoming overloaded, and
a control unit that is operatively connected to said at least one flow generating machine,
the method including the steps of:
storing a predetermined relationship in the control unit between the operational speed N of the flow generating machine and an operational parameter P, which predetermined relationship depends on a predetermined liquid flow speed V in the basin at the flow generating machine, the operational parameter P being defined as either the torque M of the flow generating machine or an operational parameter from which a torque M of the flow generating machine may be derived,
determining the operational speed N of the flow generating machine,
determining a set value of the operational parameter P of the flow generating machine from the determined operational speed N, the set value based on said predetermined relationship between the operational speed N of the flow generating machine and the operational parameter P of the flow generating machine,
determining a real value of the operational parameter P of the flow generating machine using the control unit by measuring a parameter from which the torque M of the flow generating machine can be derived, and
adjusting the operational speed N of the flow generating machine using the control unit if the real value of the operational parameter P of the flow generating machine is different than the set value of the operational parameter P of the flow generating machine.

2. The method according to claim 1 , wherein the plant comprises a treatment plant for treatment of waste water.

3. The method according to claim 1 , wherein the operational parameter P comprises the torque M of the flow generating machine.

4. The method according to claim 1 , wherein the operational parameter P comprises a current I consumed by the flow generating machine.

5. The method according to claim 1 , wherein the operational speed N of the flow generating machine is increased if the real value of the operational parameter P of the flow generating machine is greater than the set value of the operational parameter P of the flow generating machine.

6. The method according to claim 1 , wherein the operational speed N of the flow generating machine is decreased if the true real value of the operational parameter P of the flow generating machine is less than the set value of the operational parameter P of the flow generating machine.

7. The method according to claim 1 , wherein said equipment comprises a mechanical surface aerator.

8. The method according to claim 7 , wherein the mechanical surface aerator comprises a horizontal rotational axis.

9. The method according to claim 7 , wherein the mechanical surface aerator comprises a vertical rotational axis.

10. The method according to claim 1 , wherein said equipment comprises an aeration sector arranged at a bottom of the basin.

Assignees

• Xylem Ip Man Sarl

Inventors

• Uby Lars

Classifications

• C02F3/02

  Aerobic processes · CPC title

• C02F1/74

  with air (aeration of stretches of water C02F7/00) · CPC title

• C02F3/1284

  Mixing devices · CPC title

• C02F2209/40

  Liquid flow rate · CPC title

• C02F2209/006

  comprising a software program or a logic diagram · CPC title