The quality of ground water and surface water is constantly threatened by illegal discharges, sewage overflows, spills and runoff. By using continuous monitoring stations that can quickly be moved from one place to another, it is possible to trace a pollution to its source. The monitoring stations continuously measure the water quality and send an e-mail or text (SMS) alert when a pollution is detected. The responsible official can than view the measured parameters on a website and take the appropriate action.
In all cases a monitoring system consists of one or more sensors, a data logger with GPRS modem and a battery. A solar panel may be added in some cases. In most cases a simple conductivity sensor is sufficient, because most pollutants increase conductivity. Note that for detection and tracing it is not relevant to determine exactly what the polluting substance is. This can be done using grab samples, after detecting a jump in conductivity.
The monitoring systems are small and can easily be hidden. The monitoring station transmits its data by GPRS (mobile phone network) to a server. The user can view graphs and tables of the measured data using a web browser. He can set alarm thresholds for receiving alarm messages on his phone in case a parameter exceeds a threshold.
Mobile monitoring stations are typically custom build around sensors, data loggers and software.