Wireless Sensors Applications


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Applying New Technology to Environmental Sites

In a continuing initiative to apply creative solutions to environmental sites, Project Navigator, Ltd. (PNL) has recently employed wireless technology to improve the safety and efficiency of operations at two of our sites.

Potential benefits of wireless technology include:

  • Increased safety
  • Increased data accuracy and metrics
  • Increased data collection
  • Improved data management
  • Ease of use
  • Improved Operational Management
  • Adaptability
  • Long-term cost savings.

Examples of two such sites are two landfills in Southern California, the BKK and OII landfills, both of which involve remediation of hazardous waste in response to Federal or State actions.

BKK Landfill, West Covina

The BKK Class I landfill is located in the city of West Covina, and is approximately 150 acres. Operation of the site includes a number of challenges, such as management of an irrigation system and site security.

  • Effluent from the leachate treatment plant is a component of the site operation and its disposal is done by mixing effluent with potable water and using the mixture to irrigate the landfill cover. The amount of water needed to mix with the treated effluent is important to the cost of running the facility because water use is so significant that it is the largest consumer of water in the city. Achieving the precise amount of water needed to reduce the treated effluent to regulatory levels results in fluctuations in the total amount of effluent plus mix water. As a result, the amount of mixed effluent to be applied by irrigation may change daily, thereby requiring the resetting of the irrigation controller run times. To program irrigation manually is extremely time-consuming, difficult, and may result in errors in the desired run times.
  • Much of the landfill is located adjacent to residential areas and retail centers and security can be challenging. To implement security, regular patrols are made of the property boundaries during evenings and weekends, but these patrols cannot continually cover any one location, including some that may present an increased security risk.

Wireless Solutions

Using multiple innovative technologies, PNL designed and implemented a wireless system to help improve the security and irrigation controls at the landfill, and also to be available for additional uses. Closed circuit security cameras were installed at key locations to help guard against intruders and illegal activity, and also to assist security guards who cannot see these areas from their post. Video feed is transmitted to websites for monitoring as well as recording for playback to document problems and security situations.

In addition to improvements in security, all irrigation controllers were connected to the wireless network via modems and wireless transmitters, which pass data to a secure Internet website. The website allows designated staff to coordinate the irrigation scheduling to meet BKK's fluctuating water budget, and also generate reports and easily monitor data. This results in more accurate irrigation, reduces water use, and results in cost savings.

Operating Industries, Inc. (OII) Landfill, Monterey Park

OII is a 140-acre Superfund located in Monterey Park, California. Similar to the BKK site, OII is a landfill with a complex LFG collection system and a leach treatment plant. OII is also situated adjacent to retail developments and has similar security risks. Some of the operational challenges include: (1) accurate monitoring of strain in the gas wells which occur as a result of landfill settlement, and (2) real time monitoring of landfill gas well temperature. Both are difficult and expensive to do manually.

Wireless Solutions

PNL implemented a wireless system, similar to that at the BKK landfill, to increase security and operations efficiency. Wireless security cameras, viewable from the Internet, now assist the security patrol and can be monitored both from the security station as well as from any location having access to the Internet. Cameras are mounted on the access gates, key facilities, and open areas such as the top deck.

Strain sensors were installed in the gas pipe systems, and were linked to the wireless backbone in order to detect strain from settlement. This is an extremely useful parameter because the landfill settles approximately one foot per year, sometimes resulting in breaks in conveyance lines as well as shearing of well casings.

To monitor temperature, thermal probes in landfill gas wells were connected to the wireless system, which allow continuous real-time monitoring of gas well temperatures. Measurements over time are recorded in a database and field staff can detect and monitor changes in gas temperature between well adjustment cycles thus allowing maintenance personnel to “tune” wells based on the real-time temperature data and avoid surprises from unanticipated gas temperature excursions. The ability to instantly, continuously, and remotely monitor the system results in more accurate metrics, increased environmental safety, and improves overall operational management.

Other Potential Applications

One of the key benefits of wireless technology is its adaptability to various functions and needs. In addition to the current applications, other operations at environmental sites could be facilitated by a wireless system. For example:

  • Wireless instrumentation of flow monitors, pressure gauges, and totalizers, so data could be sent to a database and evaluated for non-typical status, e.g., use as leak detectors
  • Combining wireless technology with any existing PLC’s (Programmable Logic Controllers), resulting in the ability for PLC’s to be accessed remotely, without the need for data cable installation
  • Groundwater chemistry monitoring
  • Ambient air chemistry monitoring
  • Soil monitoring
  • Surface temperature monitoring
  • System alarms transmitted either by email or website-based notifications
  • Data storage, management, tracking, graphing, and prediction

These applications can be useful to any site that is undergoing remediation, including landfills, local groundwater systems, harbors and ports, and industrial sites. The ability to instantly monitor a system and collect continuous metrics allows for early detection of any potential problems, and thus, immediate action. The ability to detect and avert problems not only results in cost savings, but more importantly, reduces the safety risk to workers, the community, and the environment.

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