Systems and methods for determining a thickness of a nonaqueous phase liquid layer

1. A method for measuring a thickness of a first layer of nonaqueous phase liquid (NAPL) that is disposed adjacent a second layer of aqueous phase liquid (APL), such that an interface between the first and second layers is located at a first depth relative to a reference position, the method comprising:

determining a first pressure exerted by the first layer with a first pressure transducer assembly including a first pressure transducer, the first pressure transducer assembly having a total density value between a first density value of the NAPL and a second density value of the APL; and

calculating the thickness of the first layer based at least in part on the determined first pressure, a density of the NAPL, a density of the APL, and a distance between the interface and a pressure sensor used to measure the first pressure.

2. The method of claim 1 , further comprising determining a second pressure associated with a second depth relative to the reference position with a second pressure transducer.

3. The method of claim 2 , further comprising calculating the first depth based at least in part on the determined first pressure and the determined second pressure.

4. A method for measuring a thickness of a first layer of nonaqueous phase liquid (NAPL) that is disposed adjacent a second layer of aqueous phase liquid (APL), such that an interface between the first and second layers is located at a first depth relative to a reference position, the method comprising:

determining a first pressure exerted by the first layer with a first pressure transducer assembly including a first pressure transducer, the first pressure transducer assembly having a total density value between a first density value of the NAPL and a second density value of the APL;

determining a second pressure associated with a second depth relative to the reference position with a second pressure transducer; and

calculating the thickness of the first layer based at least in part on the determined first pressure.

5. The method of claim 4 , further comprising calculating the first depth based at least in part on the determined first pressure and the determined second pressure.

6. A method for measuring a thickness of a first layer of nonaqueous phase liquid (NAPL) that is disposed adjacent a second layer of aqueous phase liquid (APL), such that an interface between the first and second layers is located at a first depth relative to a reference position, the method comprising:

determining a first pressure exerted by the first layer with a first pressure transducer assembly including a first pressure transducer, wherein the first pressure transducer assembly floats with the interface; and

calculating the thickness of the first layer based at least in part on the determined first pressure, a density of the NAPL, a density of the APL, and a distance between the interface and a pressure sensor used to measure the first pressure.

7. The method of claim 6 , further comprising determining a second pressure associated with a second depth relative to the reference position with a second pressure transducer.

8. The method of claim 7 , further comprising calculating the first depth based at least in part on the determined first pressure and the determined second pressure.

9. A method for measuring a thickness of a first layer of nonaqueous phase liquid (NAPL) that is disposed adjacent a second layer of aqueous phase liquid (APL), such that an interface between the first and second layers is located at a first depth relative to a reference position, the method comprising:

determining a first pressure exerted by the first layer with a first pressure transducer assembly including a first pressure transducer, wherein the first pressure transducer assembly floats with the interface;

determining a second pressure associated with a second depth relative to the reference position with a second pressure transducer; and

calculating the thickness of the first layer based at least in part on the determined first pressure.

10. The method of claim 9 , further comprising calculating the first depth based at least in part on the determined first pressure and the determined second pressure.

11. The method of claim 9 , wherein the NAPL comprises a light nonaqueous phase liquid (LNAPL), the method comprising positioning the second pressure transducer at a fixed depth from the reference position and below the first pressure transducer assembly.

12. A system for measuring a thickness of a first layer of nonaqueous phase liquid (NAPL) that is disposed adjacent a second layer of aqueous phase liquid (APL) such that an interface between the first and second layers is located at a first depth relative to a reference position, the system comprising:

a pressure transducer assembly having a total density value between a first density value of a target NAPL and a second density value of a target APL,

wherein the pressure transducer assembly is configured to measure a first pressure associated with the pressure exerted by the first layer; and

a second pressure transducer configured to measure a second pressure associated with a second depth relative to the reference position.

13. The system of claim 12 , wherein the pressure transducer assembly is configured to float with the interface as the first depth of the interface changes.

14. The system of claim 12 , wherein a distance of the pressure transducer assembly relative to the interface remains constant after movement of the interface.

15. The system of claim 12 , wherein the total density value is in a range of 1.001 g/cc to 1.04 g/cc.

16. The system of claim 12 , the system having a depth resolution in a range of 0.5 mm to 30 mm.

17. The system of claim 12 , wherein the second depth is constant.

18. The system of claim 12 , wherein the second depth is greater than the first depth.

19. The system of claim 12 , wherein the NAPL comprises a dense nonaqueous phase liquid (DNAPL), and wherein the total density value is less than the first density value but greater than the second density value.

20. The system of claim 12 , wherein the second pressure transducer is connected to the reference position by a cable, the cable extending through a retrieval loop connected to the pressure transducer assembly, such that when the cable is withdrawn through the retrieval loop, the second pressure transducer engages with the retrieval loop to retrieve the pressure transducer assembly.

21. The system of claim 12 , wherein the total density value is in a range of 0.60 g/cc to 0.999 g/cc.

22. The system of claim 12 , wherein the pressure transducer assembly further comprises a floatable member, the first pressure transducer coupled with the floatable member.

23. The system of claim 22 , wherein the first pressure transducer is integrated with the floatable member.

24. The system of claim 22 , wherein the first pressure transducer is coupled to the floatable member by way of an elongate connector, such that the first pressure transducer is disposed at a greater depth than the floatable member.

25. The system of claim 12 , wherein the NAPL comprises a light nonaqueous phase liquid (LNAPL), and wherein the total density value is greater than the first density value but less than the second density value.

26. The system of claim 25 , wherein the second pressure is associated with a total pressure exerted by the first layer and the second layer.

27. The system of claim 26 , wherein the thickness of the first layer is calculated based at least in part on the first pressure, a density of the NAPL, a density of the APL, and a distance between the interface and a pressure sensor used to measure the first pressure.