The treatment plant of the ski station of Vall de Núria, went from treating the waste waters of 400 inhabitant in the 90s to receiving that of over 3,000 people in some periods.
This contamination overload has not stopped the effluent water from the trickling filters from complying with discharge limits.
Type of treatment
Location: Catalonia, Spain
Equivalent population: 461
Capacity: 97 m3/day