Solarbee – Lake Bánk – Bluegreen algae control

In Lake Bánk bluegreen algae had been a problem throughout many years. The characteristics of the lake favours the bluegreens unfortunately. High nutrient concentration, calm, still parts protected from the wind, high pH (above 9) all favours to species like Anabaena sp, Microcystis sp, and Oscillatoria sp. The bioremediation of the lake has been started in June 2007, as a result of this the improvement of the water quality was reasonable, in the meantime we managed to keep the numbers of other algae species like diatomes and green algae under control. But unfortunately the nutrient concentrations in the lake are much above the limiting concentrations for bluegreens.

The local government of settlement Bánk asked us to control the bluegreens as well. Considering the facts above the only solution for bluegreen algae control was the continuous movement of the entire water quantity of the lake both horizontally and vertically.

The available equipment for the above described task is a SolarBee SB10000 v12 which was installed on the middle of the lake surface in 10th August 2007. Setting the suction depth for 1.5 m we totally focused on bluegreen algae control. For the time of installation the blooming of Microcystis had begun, like in case of many other Hungarian lakes with similar characteristics to this lake. On the 2nd week after installation the number and size of the bluegreen scums floating on the water’s surface significantly reduced, and after a few days they totally disappeared unlike in case of other lakes, where due to the warm autumn, bluegreen blooms lasted till the end of October.

In October 2007, after the temperature started dropping significantly, and the fear of bluegreens disappeared, we lowered the suction depth to 3 m in order to bring more DO to the lower segments of water, and by this decreasing the size of the anoxic zone. After 1 week of lowering the hose, in 3 m depth the DO level increased from 0.76 mg/l to 5.76 mg/l at the same measuring point defined by GPS.

On the day of installation of the SolarBee 1.

On the day of installation of the SolarBee 2.

10 days after installing the SolarBee 1.

10 days after installing the SolarBee 2.

Installatation of Solarbee

Arrival to Hungary

Assembling

Lifting the SolarBee onto the water

SolarBee in its final position on the lake