Lake Gołdap is a reservoir that occupies an area of 204.4 hectares, 149 of which are within Polish borders. The reservoir is a polymictic lake relatively mixable in the forming period of thermal stratification with distinctive thermocline. In the past, Lake Gołdap was affected by pollution coming from agricultural production and recreation activities, as well as it was the receiver of impurities carried by the Jarka river (now the Gołdapa river).
As a result, the lake contains rather high concentration of phosphorus, which is responsible for harmful algae blooms that led to deterioration of water quality, health hazards and unpleasant smell.
In October 2016, Gołdap commune obtained a consent from the Marshal of Warmian-Mazurian Voivodship to introduce algae growth prevention substance into Lake Gołdap in the amount of 300 tons.
It was decided to use Phoslock® preparation – bentonite modified with lanthanum that binds phosphates. The preparation was devised at the beginning of the year 2000 by a renowned Australian research company CSIRO (Commonwealth Scientific and Industrial Research Organisation). Phoslock® permanently binds phosphates creating biologically neutral mineral called Rhabdophane. The new mineral becomes a part of natural sediments of the lake. Phoslock removes the excess of phosphate from water, which significantly reduces the growth of harmful algae.
So far, Phoslock has been successfully used in more than 250 water reservoirs around the world but Lake Gołdap is the first large reservoir in Europe reclaimed using this method. The whole project was carried out together with Phoslock Europe GmbH. The first stage of introducing 150 tones of the preparation finished in December. The second stage is scheduled for the beginning of April.
The introduction was carried out using a special platform equipped in a mixing system with a distribution nozzle and a monitoring system (GPS, depth sensors, etc.). The preparation kept in 1.05 ton bags was mixed with lake water and distributed a few centimeters under the water table. During the first stage, the preparation was introduces on areas where the lake depth was equal or more than 5m (the maximum depth of the lake is 10.6m).
Constant monitoring carried out before, during and after the distribution process is an integral part of the project. Detailed analysis will be presented after the second stage. Video footage from the first stage is available at kanale YouTube .