Grantee Research Project Results
Final Report: Wireless Underwater Telemetry System for Surface Water Quality Monitoring
EPA Contract Number: EPD04049Title: Wireless Underwater Telemetry System for Surface Water Quality Monitoring
Investigators: Schaefer, Philip
Small Business: Vortant Technologies LLC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2004 through August 31, 2004
Project Amount: $69,338
RFA: Small Business Innovation Research (SBIR) - Phase I (2004) RFA Text | Recipients Lists
Research Category: Drinking Water , SBIR - Water and Wastewater , Small Business Innovation Research (SBIR)
Description:
The goal of this research project was to create a product to revolutionize the ease, flexibility, and cost-effectiveness of installing and using in situ, real-time water quality monitoring systems. Currently, most real-time surface water quality monitors use submerged sensor probes, with vulnerable, potentially long electrical cables connected to a surface meter box or floating buoy. In practice, finding acceptable installation locations and installing the cables, enclosures, and antennas is quite difficult, and such systems are prone to intentional or accidental damage.
With the new technology being introduced in this project, however, a complete wireless water quality monitoring system can be packaged as a stand-alone, entirely submersible unit, which is simply placed invisibly underwater at any desired depth in the lake or stream of interest. Unlike previous radio-based telemetry approaches, this new telemetry system is capable of transmitting signals from deep underwater locations to a remote receiving station, located at a convenient site on land, possibly many miles from the monitoring point.
This type of telemetry was not possible in the past because radio waves are severely attenuated in water. For example, at more than a few feet in depth, nearly all of the energy in a radio wave at most practical frequencies is absorbed by the conductivity in the water. The main technical innovation of Vortant Technologies, LLC’s project is a new way of generating signals underwater that does not suffer from this limitation. Unlike sonar waves, this innovation allows the telemetry to be received on land, far from the surface of the water.
Benefits of the resulting product, currently named the Wireless Water Quality Telemetry System (WQTS), include: (1) complete elimination of the cables and electrical wiring from the underwater sensor to above-water electronics or antennas; (2) elimination of inadvertent damage to the water quality monitoring station because of boat propellers, recreational activities, etc., contacting the cabling or the ground-based electronics; (3) increased security of water quality monitoring stations in drinking water reservoirs against intentional damage or destruction from vandalism or terrorist-related activities; and (4) significantly reduced visibility of the monitoring station in recreational or pristine scenic areas.
Summary/Accomplishments (Outputs/Outcomes):
The project consisted of design activities and field experiments to demonstrate the feasibility of the new water quality monitoring and telemetry technology.
In Task 1, a database of water quality applications that can benefit from the new technology was constructed. This database includes the specific monitoring sensor instruments, locations within lakes or streams, depths in the water, and data sampling and reporting frequency for each application. For example, the primary application identified in this database is monitoring of drinking water reservoirs for harmful pollutants. The database was used to define technical requirements for the WQTS system and the Phase I field testing needed to demonstrate feasibility.
Task 2 included the majority of the electronics design activities. In this task, a microcontroller-based system was designed to control and obtain data from water quality instruments (sensors), organize the acquired data into digital packets, control the frequency and modulation of a signal-generation module, and amplify the modulated signal for transmission through the water.
In Task 3, an innovative mechanism was constructed to couple signal transmission energy into the water from the amplified signal provided by the electronics. This included constructing both the actual transducer elements that perform the coupling as well as the mechanical housings and structure needed to contain the submerged, underwater WQTS unit.
In Task 4, the complete WQTS system was tested in the laboratory. A completely integrated WQTS was used in these experiments, containing all of the electronics, transducer mechanisms, and power supplies. Under the direction of the project participants from the University of North Carolina, Asheville, a large aquarium with controlled conditions was used. Three water quality parameters within the aquarium water were varied in the experiments; after each variation the received output from the WQTS was compared separately to the output of the direct, wired water quality instrument. Successful comparison of the data from both sources indicated that the WQTS properly interfaces to both the water quality instruments and telemetry components. It also was verified that no undesired interactions between the components occurred.
Task 5 involved assembly of a land-based telemetry receiver station for Phase I WQTS testing. In this task, a combination of commercially available receiver technology and custom demodulation components was assembled. The complete station was integrated into a portable, battery-powered crate that can be taken into the field and used to receive telemetry at large distances from the WQTS transmitter unit.
In Task 6, a mechanical release mechanism was selected. The release mechanism is used to allow retrieval of the underwater WQTS in field operations for maintenance or removal.
In Task 7, the Phase I test scenarios were defined. Based on the applications matrix developed in Task 1, a series of test scenarios were generated such that the major technical feasibility issues could be examined. Scenarios both for lake and stream applications were defined for the Phase I testing.
Task 8 included the actual Phase I field testing. The testing included visiting lakes and streams and testing for various parameters, including distance to the receiver, depth in lakes, and types of terrain over which the system operated. The Task 8 field testing was highly successful, and all test criteria were met, indicating that the WQTS technology is feasible for many water quality monitoring applications. Strong signals were received over many miles and up to the maximum 50 foot depth attempted.
Task 9 was a cost analysis task. The components comprising the Phase I system were used to estimate the impact on cost from the perspective of manufacturing and assembling the basic technology units. The analysis indicated that it should be very feasible to construct the WQTS units available at a cost that is quite competitive with that of other water quality monitoring approaches.
Conclusions:
Laboratory testing verified that the WQTS approach is feasible for interfacing with standard, commercially available water quality sensing instruments, and that it is straightforward to integrate the WQTS system components into a working system. Power drain measurements and calculations showed that the product is very conservative in battery usage and can operate continuously for months in the field using low-cost battery packs. Using this equipment, successful water quality telemetry transmission was demonstrated over many miles both from stream locations, as well as from deep lake monitoring locations. Also, these results were obtained without the use of any overly exotic or esoteric electronic or mechanical components, indicating that the cost of the WQTS product will be competitive with that of older cable-based technologies. The combination of applications analysis, laboratory system testing, field testing in realistic lake and stream scenarios, and cost analysis indicates that the WQTS product is a highly feasible and practical approach to water quality monitoring for a wide variety of remote and continuous applications.
Supplemental Keywords:
surface water quality, monitoring, drinking water, underwater telemetry, Wireless Water Quality Telemetry System, WQTS, terrorism, contaminant, sensor, real-time environmental monitoring, radio wave, sonar, SBIR,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Monitoring/Modeling, Environmental Monitoring, Drinking Water, Environmental Engineering, monitoring, wireless underwater telemetry system, underwater telemetry system, water quality, drinking water contaminantsThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.