Hazardous cyanobacteria integrity response to velocity gradient and powdered activated carbon in water treatment plants

Although some studies have investigated the impact caused by chemicals used on water treatment (coagulants and oxidants) cyanobacteria integrity, isolated effect of shear stress during coagulation is still not fully understood. This study evaluated different velocity gradients, mixing times, addition powdered activated carbon (PAC) integrity Microcystis aeruginosa, Raphidiopsis raciborskii, Dolichospermum circinale, known producers toxin taste odor (T&O) compounds. No association was found between R. raciborskii cell lysis gradient, with or without PAC, demonstrating high resilience this taxon to stress. In contrast, an for M. aeruginosa at highest gradient (1000 s−1) D. circinale above lowest studied (600 s−1). After PAC addition, there a reduction in chances finding intact cells 800 s−1 45 s, while show all scenarios expect 600 10 s agitation. The additional may lead more release metabolites shows need adjust hydraulic conditions rapid stage, especially when “fragile” are present. Neither cyanobacterial size nor morphology shown be relevant sensitivity, indicating that wall composition might been important factor controlling lysis.