Solar power for valve terminals in the water industry

The manual operation of remote decentralised plants such as rainwater retention basins is costly in terms of both time and money. Energy-autonomous automation with photovoltaic or wind power could provide a solution to this problem.

Rainwater retention basins catch surplus water from sewers during heavy rainfall, thus protecting wastewater treatment plants and natural bodies of water from overload. Once the wastewater treatment plants in question have sufficient capacity again, the gate valves on the retention basins are opened and an appropriate amount of water is released. Since the plants are often located in places without electricity supply, it was previously necessary to operate the gate valves manually, which meant a time delay and associated labour costs.

An energy-autonomous solution from Festo can now be used to actuate the gate valves automatically by remote control. A photovoltaic or wind-power system supplies the necessary electricity for the operation of this valve terminal solution and a compressor generates compressed air.

Using a GSM modem, the entire system can be controlled and monitored remotely from the control room of a wastewater treatment plant. The opening and closing of the slide valves as well as the status monitoring for the entire system can also be performed centrally.

The flow control gate valves are actuated with pneumatic linear actuators type DFPI and DLP, some of which are equipped with positioners. The pneumatic actuators are suitable for outdoor installation, often required in the water industry.

The energy-autonomous station is individually dimensioned in terms of size and performance. Among the most important parameters are:

• Location-specific data such as exposure to sunlight, orientation, presence of shade.
• Logging of the energy consumption profile on the basis of type of consumption, hours of operation, total operating period.
• Definition of length of period of autonomous operation required to ensure safe operation in the case of an energy source failure.

Advantages of this energy-autonomous pneumatic solution include: a plant without mains power can be remotely operated; operators can save time and money on manual operation; and it can provide continuous monitoring of the system.