Microfiltration and ultrafiltration for treatment of lake water during algal blooms

In this study, pressure driven ceramic membranes for microfiltration (MF) and ultrafiltration (UF) were used to improve the quality of waters in lakes. Four urban lakes located in the city of Olsztyn and belong to the Masurian Lake District: Track (53 degrees 47'21 '' N; 20 degrees 32'24 '' E), Podkowka (53 degrees 47'2 '' N; 2082701 '' E), Tyrsko (53 degrees 48'18 '' N; 20 degrees 25'21 '' E), and Redykajny (53 degrees 48'55 '' N; 20 degrees 25'4 '' E) were examined. The effects of the composition of lake water from different photic zones and of the type of membrane on the efficiency of removal of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were investigated. The average efficiencies of rejection were 71.6 +/- 5.8% (TOC), 16.0 +/- 5.7% (TP) and 19.6 +/- 9.3% (TN), independently of the composition of the feed and the type of membrane. Due to the similar average permeate fluxes of 2.2 +/- 0.1 L/(m(2) min) and water recoveries of above 85% in MF and UF, the use of MF is suggested because it has lower operational costs than UF. Because membrane filtration of waters from the zones with the highest chlorophyll contents was very effective both in terms of efficiency of pollutant rejection and hydraulic parameters of membranes, this technology can be used for selective treatment of parts of water with the highest phytoplankton abundance. (C) 2019 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.