Geograph - photograph every grid square

This plant just south of the village would appear to be of the reed bed kind. Also known as artificial wetland systems, Constructed reed bed systems are the reconstruction of freshwater wetland ecosystems to treat wastewater. They are often used in combination with other conventional treatment facilities, including septic tanks. Most reed bed models are land-intensive, but they are highly energy-efficient (requiring no energy for treatment processes) inexpensive to build, low maintenance, productive, have minimal sludge generation, are aesthetically appealing, and create valuable habitat for wildlife.
Taken from Link

See SP0438 : Sewage treatment