A Texas based company with waste management sites around North America have installed electrical generation plants at various locations that use methane collected from the waste. The daily operation of these sites include the management of the leachate, a liquid waste by-product of decomposition, and the collection of gas for electricity production. This is typically carried out at multiple wells distributed all across the waste management site. There are a number of safety and operational factors involved with this including:
- Leachate must not allowed to overflow the liner and contaminate the surrounding ground water.
- Maintaining low leachate levels significantly improves the formation of methane gas and hence the production of electricity.
- When leachate is pumped out the wells the flow rate must be monitored and controlled to ensure that the drainage system is not overloaded.
Leachate levels are normally measured manually at each well several times a day throughout the year. Currently, the method to obtain this data is to visit each well location throughout the site and manually record flow rate data from a local display. In addition, well depth is measured by inserting a commercial water surface detect tape down the well. There are many drawbacks to the manual collection of this process including:
- Time consuming
- Inaccurate (human error, foaming at the top of the leachate etc)
- Often difficult to reach some wells in harsh weather
- Oxygen enters the system when the well cap is removed to insert the measuring tape (well is normally kept under partial vacuum)
Wireless Options distributed intelligent wireless systems (IWS) have developed a system that overcomes the manual collection of this data and removes the drawbacks above. The mesh wireless systems have been installed at a number of sites to remotely measure and report well depth and leachate pump flow rate. Gas flow rate measurement is being added to the system in late 2010. The hub site provides an Ethernet termination into a central database for all traffic.