Exploratory Advanced Research . . . Next Generation Transportation Solutions

Remotely Monitoring Water Quality Near Highways

A Sustainable Solution

A Self-Sustained Sensing System 

The innovation of this project’s research is that it 

combines the remote monitoring capabilities of 

in situ sensors with renewable and self-sustaining 

bio-energy generation. Instead of batteries, the 

wireless sensors are powered by microbial fuel 

cells (MFC) that generate electricity through 

electrochemical reactions with a type of common and safe bacteria (magnesium oxidizing 

microorganisms) ubiquitous to streams. Researchers designed MFCs that can essentially function 

as batteries when there is little microbial activity 

in the stream but operate as MFCs when significant microbial activity occurs. These MFCs differ 

from traditional ones that tend to have low energy 

generation and limited scalability. Because the 

energy generated from MFCs can fluctuate, a 

power management system regulates the voltage 

to provide a stable and accurate direct current 

voltage that can power the sensors and support 

a control system that collects, processes, and 

transmits the real-time water quality data.

Field Tests

Project researchers first tested the MFC in their 

laboratory at Montana State University. After 

placing the MFC into a plastic tank filled with harvested pond water, researchers connected it to 

a varied resistive electrical load. After several 

months of laboratory tests, researchers conducted a 5-week field test in a stream located at the 

intersection of 11th Avenue and Opportunity Drive 

in Bozeman, MT. During the test, the researchers 

investigated the stability of the MFC’s power output and recorded the output voltages three times 

a day. To increase the amount of energy provided 

by the MFC, project staff redesigned the power 

management and sensor network systems after 

the initial field test so that harvested energy 

would be used more efficiently. Researchers then 

conducted a 3-month test of the entire system, 

including a waterproof floating sensor enclosure, 

in the same stream. A device that could float was 

key to the sensors’ successful operation, as the 

wireless signals cannot penetrate water. 

The Exploratory Advanced Research Program Fact Sheet

Collecting water quality data on 

streams located near highways can 

be challenging in remote and difficult-toreach locations. Obtaining and transporting water samples is time-consuming, 

expensive, and sometimes dangerous. 

Another key challenge is that transportation agencies can miss the release of 

toxins and pollutants that occur in a short 

time period or the first flush of stormwater 

runoff from highways. Collecting water 

quality data is crucial, however, to State 

departments of transportation in their 

effort to meet U.S. Environmental 

Protection Agency National Pollutant 

Discharge Elimination System permit 

requirements, particularly during the 

first flushes of spring stormwater runoff. 

Placing sensors directly in the water 

to collect data is an appealing solution, 

but these in situ sensors typically rely 

on batteries that have to be replaced 

as often as every 3 weeks. Designing 

a renewable and self-sustaining onsite 

system is the goal of the Exploratory 

Advanced Research (EAR) Program 

project “A Remote, Self-Sustained 

System for Monitoring Water Quality 

Near Highways.” Montana State 

University conducted this research, 

which was funded by the Federal 

Highway Administration (FHWA).
Key Findings

Among the key findings resulting 

from the field test is that environmental conditions, including water 

flow rate, pH, temperature, dissolved oxygen concentration, 

and chloride concentration, were 

significant factors affecting the 

MFC’s power output. The MFC 

required 4 to 6 hours to harvest 

enough energy to boost the energy management 

circuit. This energy was collected by the power 

management system, which then released enough 

power in short but sufficient periods for the 

sensors and communication devices to operate. 

The output power voltage generated by the MFC 

remained stable during the field testing. Overall, 

the sensing system continuously provided water 

quality data during the testing, including pH, 

temperature, and chloride levels. Data frequency 

ranged from four to seven samples a day.

Future Work

The project researchers successfully demonstrated 

the concept of using MFCs as a self-sustainable 

power supply to collect remote water quality data. 

Future work is needed to enhance the capability, 

performance, reliability, and cost-effectiveness 

of the technology and make it market-ready. In 

particular, improvements are needed to increase 

the energy output of the MFCs and integrate 

acoustic communication modules into the sensors to increase the wireless communication 

range. At present, the communication range is 

limited because the signals cannot penetrate 

water. Other issues to address in future work are 

the feasibility of protecting the system from 

wildlife and severe weather conditions.

Importance to FHWA

The proposed system would extend the operational time of sensors deployed in streams and 

result in significant benefits, including reduced 

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research 

(EAR) Program focuses on longer term, 

higher risk research with a high payoff 

potential. The program addresses underlying gaps faced by applied highway 

research programs, anticipates emerging 

issues with national implications, and 

reflects broad transportation industry 

goals and objectives. To learn more about 

the EAR Program, visit the EAR Web site 

at www.fhwa.dot.gov/advancedresearch. 

The site features information on research 

solicitations, updates on ongoing research, 

links to published materials, summaries of 

past EAR Program events, and details on 

upcoming events. 

Remotely Monitoring Water Quality Near Highways

A Sustainable Solution

Publication No. 

FHWA-HRT-16-018

HRTM-30/11-15(WEB)E

maintenance costs and increased safety for 

State transportation agency staff involved in 

water quality monitoring. As agencies contend 

with limited budgets, being able to remotely 

monitor targeted streams means that staff 

experts can avoid spending considerable time 

conducting routine and repetitive tasks in 

the field. The end result is that agencies can 

improve their operational efficiency while still 

meeting crucial environmental protection and 

water quality needs.

Learn More

For more information on this project, contact 

Marcel Tchaou in the FHWA Office of Project 

Development and Environmental Review, 

202-366-4196 (email: marcel.tchaou@dot.gov).

© Qing Yang, Montana State 

University.

Microbial fuel cells power in situ 

sensors to remotely monitor 

water quality. The fuel cells 

generate electricity through 

electrochemical reactions with 

a type of bacteria ubiquitous 

to streams.

Photo credit, page 1: 

© Qing Yang, Montana State 

University

The project’s control system 

collects, processes, and 

transmits the real-time water 

quality data provided by the 

in situ sensors.