Nagybivalyos Lake System, Lake S2 Felső

Nagybivalyos-tórendszer, S2 Felső-tó

Nagybivalyos Lake System consists of 4 fishing lakes. The source of the water quality problems of all lakes is that they are very close to the location of the tertiary treatment pond of the wastewater treatment plant of city Várpalota. This causes a huge load of nutrients and organic material, due to that the lakes are in hypertrophic conditions. The S2 Felső is the second largest lake of the system in area, the operator is just putting big fish in it (above 5 kg weight).

Algae and aquatic weed blooms had been very serious during the summer seasons in the past. Yearly sludge production is high, and because of the low DO levels in the water column, the sludge is not stable, but rotting with odorous gas formation. Bioremediation of the lake has started in July 2007. The process has had an outstanding success even in the initial year. We have prevented the lake from algae blooms, we have stopped the blooming of aquatic weeds, the DO levels have been stabilized quickly throughout the whole water column which has had an effect in the stabilization of the sludge zone, and by this the removal of odor. Water quality has improved very significantly as the table shows below.

NAGYBIVALYOS S2 14th June 2007. 24th September 2007.
Ammonium mg/l 0,82 0,12
Free Ammonia mg/l 0,09 0,005
Nitrite mg/l 0,24 0,17
Nitrate mg/l 37,21 18
Ortophosphate mg/l 0,31 0,09
Total Algae Count / ml 28 121 10 200