Connection of sewage treatment plants and wastewater treatment plants via public networks – EWE Netz GmbH – Division: Water | Wastewater

The challenge

The connection of sewage treatment plants and wastewater treatment plants is to be achieved with a telecontrol system that guarantees communication paths without failures in compliance with current laws, regulations and standards. Where copper cables are available, Ethernet modems are used to transmit all important measurement and control data. Unfortunately, not all systems can be reached via copper or fibre optics.


LTE VPN routers and an OpenVPN Security Server (VSS-01) are used for the outstations where no copper cable or fibre optic infrastructure is available. As a redundant server system and central VPN gateway, the VSS server manages the VPN connections and controls access to the outstations. Our routers are read out by the WAGO PLCs used on site via SNMPv3 in order to provide important information to the control centre via the 104 protocol.

Products for this solution


  • The existing copper/fibre optic infrastructure can continue to be used and an LTE solution can be used for the external stations. This avoids the expansion of copper and fibre optic lines. The operating costs and investment costs for the LTE solution are low.
  • The VPN technology enables secure authentication and strong encryption so that only authorised persons can access confidential company data – especially when transmitting via public networks. With DigiComm’s VSS solution, all participants – including those in the company’s own network (e.g. the control system) – must establish a connection to the VSS-01 server. This allows certified users to communicate with each other using VPN encryption.