Regulating air velocity continuously injected into biological water treatment reactor

• US 7,407,584 B2
• Filed: 05/27/2005
• Issued: 08/05/2008
• Est. Priority Date: 06/02/2004
• Status: Expired due to Fees

• Current Assignee: Veolia Water Solutions & Technologies Support
• Original Assignee: OTV SA SA
• Inventors: Payraudeau, Michele, Lemoine, Cyrille
• Primary Examiner(s): Barry; Chester T
• Application Number:
  US11/569,924
• Publication Number:
  US 20070221580A1
• Time in Patent Office: 1,166 Days
• Field of Search: 210/614, 210/620, 210/220, 210/150
• US Class Current: 210/614
• CPC Class Codes: C02F 2101/16 Nitrogen compounds, e.g. ammonia
• CPC Class Codes: C02F 2209/14 NH3-N
• CPC Class Codes: C02F 2209/22 O2
• CPC Class Codes: C02F 2209/38 Gas flow rate
• CPC Class Codes: C02F 3/006 Regulation methods for biological treatment
• CPC Class Codes: C02F 3/02 Aerobic processes
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage

Abstract

A method of treating wastewater wherein the biomass associated with the wastewater is subjected to simultaneous nitrification and denitrification in a single reactor. The method entails directing a wastewater influent stream into the reactor and measuring the concentration of N—NH₄ in the influent wastewater stream at a point upstream from the reactor. Air is supplied to the reactor for aerating the biomass in the reactor. The method includes controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—NH₄.

Claims

1. Water treatment method, using a biological reactor in order to abate the nitrogenous pollution called the input content contained in said water, said reactor integrating a biomass aerated by injection of air, said method including at least one step for regulation of the velocity of said injected air,

characterized in that it includes a continuous measurement of said input content of N—

NH₄ (CV_EDD) contained in said water, said input content being measured and weighted by an offset in time to deduce a control for velocity Vair of said air to be injected as a function of time.

2. Water treatment method set forth in claim 1, characterized in that said regulation step is based on the following air velocity control law as a function of time:

Vair(t)=α

(H(t)*CV_EDD(t)−

CV_setvalue)+β

in which CV_setvalue is an output set value and H(t) is the inverse Laplace transform of a phase delay function H(S).

3. Water treatment method set forth in claim 1, characterised in that said regulation step is based on a control law, as follows:

Vair(t)=α

(H(t)*CV_EDD(t)−

CV_setvalue)+β

.

4. Water treatment method set forth in claim 3, characterized in that said phase delay function is of the following type:

5. Water treatment method set forth in claim 1, characterized in that the method includes at least one step to measure an output content (Cv_s) and/or a dissolved ammonium concentration contained in said treated water.

6. Water treatment method set forth in claim 5, characterized in that said measurement of said output content (Cv_s) is used to adjust said set value by application of the following equation:

7. Water treatment method set forth in claim 5, characterised in that said measurement of an output content (Cv_s) and/or a concentration of dissolved ammonium contained in said treated water, is made continuously.

8. Water treatment method set forth in claim 6, characterized in that the method comprises a transformation step of said signal e(t) made such that:

if e>

0, f(e)=e

if e≦

0, f(e)=1−

exp(−

k,e), where k>

0.

9. A method of controlling the aeration of biomass in a reactor that simultaneously performs nitrification and denitrification on wastewater in the reactor, comprising:

directing a wastewater influent stream into the reactor;

measuring the concentration of N—

NH₄ in the influent wastewater stream at a point upstream from the reactor;

supplying air to the reactor for aerating the biomass in the reactor; and

controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—

NH₄ modified by a time difference factor.

10. The method of claim 9 including basing the time difference factor on a mathematical model.

11. The method of claim 9 wherein the time difference factor relates to a transient time from the point of measuring the N—

NH₄ concentration to a location in the reactor.

12. The method of claim 9 including directing an effluent wastewater stream from the reactor;

measuring the concentration of N—

NH₄ in the effluent wastewater stream at a point downstream from the reactor; and

controlling the quantity of air introduced into the reactor based in part on the measured concentration of N—

NH₄ in the effluent wastewater stream.

13. The method of claim 12 including basing the time difference factor on a mathematical model.

14. The method of claim 9 including continuously measuring the N—

NH₄ concentration in the wastewater influent stream and continuously controlling the quantity of air introduced into the reactor based on the measured concentration of N—

NH₄ and the time difference factor.

15. The method of claim 9 wherein the time difference factor is a function in part at least of:

16. The method of claim 9 wherein controlling the quantity of air introduced into the reactor includes controlling the velocity of the air introduced into the reactor.

17. The method of claim 16 wherein the velocity of the air introduced into the reactor is a function, in part at least, of the measured concentration of N—

NH₄ in the influent wastewater stream and N—

NH₄ output set value.

18. A method of controlling the aeration of biomass in a reactor that simultaneously performs nitrification and denitrification on wastewater in the reactor, comprising:

directing a wastewater influent stream into the reactor;

measuring the concentration of N—

NH₄ in the influent wastewater stream at a point upstream from the reactor;

supplying air to the reactor for aerating the biomass in the reactor; and

controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—

NH₄ and a mathematical model.

19. The method of claim 18 wherein the mathematical model includes a time difference factor.

20. The method of claim 18 including directing an effluent wastewater from the reactor, measuring the concentration of N—

NH₄ in the effluent wastewater stream at a point downstream from the reactor; and

controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—

NH₄ in the effluent wastewater stream.

21. The method of claim 18 including continuously measuring the N—

NH₄ concentration in the wastewater influent stream, and continuously controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of N—

NH₄.

22. The method of claim 19 wherein the time difference factor is a function in part at least of:

23. A method of treating wastewater by simultaneously performing nitrification and denitrification in a single reactor, comprising:

directing an influent wastewater stream into the reactor;

directing air into the reactor and aerating biomass associated with the wastewater in the reactor and simultaneously nitrifying and denitrifying the biomass in the single reactor;

measuring the concentration of nitrogenous pollutants in the wastewater stream upstream from the reactor; and

effectuating simultaneous nitrification and denitrification by controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of the nitrogenous pollutants.

24. The method of claim 23 wherein the nitrogenous pollutants include N—

NH₄ and the method includes measuring the concentration of N—

NH₄ in the wastewater stream upstream from the reactor.

25. The method of claim 23 including controlling the velocity of air introduced into the reactor based in part at least on the measured concentration of the nitrogenous pollutants.

26. The method of claim 23 including controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of the nitrogenous pollutants modified by a time difference factor.

27. The method of claim 24 including directing an effluent wastewater stream from the reactor;

measuring the concentration of the nitrogenous pollutants in the effluent wastewater stream at a point downstream from the reactor; and

controlling the quantity of air introduced into the reactor based in part at least on the measured concentration of the nitrogenous pollutants in the effluent wastewater stream.

28. The method of claim 23 further including controlling the quantity of air introduced into the reactor based in part at least on a time difference factor.

29. The method of claim 26 wherein the time difference factor is a function in part at least of:

30. The method of claim 23 including controlling the quantity of air introduced into the reactor based in part on a mathematical model.