OPTIMIZATION OF MEMBRANE-BASED DRINKING WATER TREATMENT PROCESSES DURING CYANOBACTERIAL BLOOMS
Globally, the number of drinking water sources with cyanobacterial blooms is predicted to increase by at least 20% until 20501. Many cyanobacterial genera are harmful, producing several potent toxins. In addition, their extracellular products can interfere with drinking water treatment processes and deteriorate product water quality (e.g.., production of DBP). Drinking water utilities have experienced huge problems associated with cyanobacteria blooms. Cyanobacterial blooms often prompt cities to shut down drinking water treatment plant or issue “Do Not Drink” advisories, leaving million residents without potable water for several days. In response to this, research on cost effective and safe drinking water production during cyanobacterial blooms has become a priority.
The application of low pressure membranes (LPMs) for drinking water treatment has experienced accelerated growth in the past decade due to their superb efficacy in high quality water production, small footprint and relatively low costs2. With pore size ranging from 10 to 100 nm, LPMs are effective in removing cyanobacterial cells but not effective for dissolved substances such as DBP precursors and cyanotoxins. During cyanobacterial blooms, algae, bacteria, exudates, and nutrients are present in high concentrations; thus, each offers the potential to foul membranes. To improve contaminants removal and fouling resistance, an important trend in membrane water treatment is the integration of coagulation pretreatment.
The principal objective of this investigation is to elucidate the key parameters and fundamental relationships governing the efficacy of coagulation pretreatment for simultaneously enhanced cyanotoxins removal and membrane fouling control in LPM processes (microfiltration and ultrafiltration).
1. UNDESA., Back to our Common Future: Sustainable Development in the 21st Century (SD21) Project, 2012;
2. Freeman, S. et al., J. Am.Water Works Assoc 98: 26-30, 2006
Image: Taken by Matt Burgi
