GPRS remote control of the supply of drinking water and disposal of wastewater within the catchment area of Rennerod
In the low mountain range of the Hohen Westerwald, lies the association municipality of Rennerod. Covering an area of 133 square kilometers, it includes 23 villages with a total of about 17,400 inhabitants. The center is the town of Rennerod (approx. 4,200 inhabitants), the seat of the administration and the central supply point of the municipality.
The water supply and sewage disposal is ensured by the municipal utility "Verbandsgemeindewerke Rennerod". This includes 34 deep wells and elevated tanks with approx. 190 km of supply lines for the drinking water supply as well as 11 sewage treatment plants and 48 rainwater structures for wastewater disposal.
The previous telecontrol system for monitoring and controlling the drinking water supply and wastewater disposal for the Rennerod association municipality was based on trunked radio. This type of data transmission is outdated and can therefore no longer be expanded in the long term. It was therefore necessary to replace this with a new telecontrol system, above all to enable future systems to be connected without any problems. The decision was made in favor of the GPRS mobile radio service, since GPRS reception is available throughout the area of the municipality.
The measurement data from the individual stations (e.g., elevated tanks, deep wells, stormwater overflow basins), some of which are located kilometers away, are transmitted to the central office around the clock via this type of M2M communication, thus enabling continuous monitoring of the structures. Any faults that may occur can thus be detected and rectified in a timely manner. Whereas maintenance personnel previously had to visit each station individually to evaluate the respective data and fault messages, these now converge in the central control system and can thus be viewed at a glance.
Although the stations are constantly online, the costs per system remain below 10 euros per month, which is now cheaper than a telephone connection. During project planning, the individual stations were gradually converted to the new system, which did not affect the operation of the plant.
Depending on the requirements, the stations have controllers from the manufacturers Siemens or WAGO for recording the operating data. For this purpose, automation functions are also performed by the controllers. The physical data communication between the outstations and the control center is regulated by WEB connectors, which can temporarily store the important process data for several days in the event of a connection failure. Secure access via VPN enables the plant manager to access the plant data from home.
A process control system with Wizcon Supervisor is used to visualize the measured values and influence the processes in the stations. This is installed on a separate server in the town hall of Rennerod. Further operator stations are set up at the sewage treatment plant (wastewater disposal) and in the city's building yard (drinking water supply).
In the event of a fault, the responsible maintenance personnel is notified by SMS with details of the exact fault via the on-call schedule integrated in the control system. The necessary reporting is done via ACRON. Here, daily, monthly and annual reports of the process data can be generated for proof at the corresponding monitoring authority. Special mention should also be made of the possibility of remote programming of all the controllers used via GPRS. This eliminates the need for on-site intervention in the event of any changes in the PLC programs.
Water supply / wastewater disposal