Coagulant plus ballast technique provides a rapid mitigation of cyanobacterial nuisance

TY - JOUR

T1 - Coagulant plus ballast technique provides a rapid mitigation of cyanobacterial nuisance

AU - Noyma, Natalia P.

AU - de Magalhães, Leonardo

AU - Miranda, Marcela

AU - Mucci, Maíra

AU - van Oosterhout, Frank

AU - Huszar, Vera L. M.

AU - Marinho, Marcelo M.

AU - Lima, Eduardo R. A.

AU - Lürling, Miquel

N1 - 6325, AqE; Data archiving: data property of and archived at WUR

PY - 2017/6/9

Y1 - 2017/6/9

N2 - Cyanobacteria blooms are a risk to environmental health and public safety due to the potent toxins certain cyanobacteria can produce. These nuisance organisms can be removed from water bodies by biomass flocculation and sedimentation. Here, we studied the efficacy of combinations of a low dose coagulant (poly-aluminium chloride—PAC—or chitosan) with different ballast compounds (red soil, bauxite, gravel, aluminium modified zeolite and lanthanum modified bentonite) to remove cyanobacterial biomass from water collected in Funil Reservoir (Brazil). We tested the effect of different cyanobacterial biomass concentrations on removal efficiency. We also examined if zeta potential was altered by treatments. Addition of low doses of PAC and chitosan (1–8 mg Al L-1) to the cyanobacterial suspensions caused flock formation, but did not settle the cyanobacteria. When those low dose coagulants were combined with ballast, effective settling in a dose-dependent way up to 99.7% removal of the flocks could be achieved without any effect on the zeta potential and thus without potential membrane damage. Removal efficacy was influenced by the cyanobacterial biomass and at higher biomass more ballast was needed to achieve good removal. The combined coagulant-ballast technique provides a promising alternative to algaecides in lakes, ponds and reservoirs.

AB - Cyanobacteria blooms are a risk to environmental health and public safety due to the potent toxins certain cyanobacteria can produce. These nuisance organisms can be removed from water bodies by biomass flocculation and sedimentation. Here, we studied the efficacy of combinations of a low dose coagulant (poly-aluminium chloride—PAC—or chitosan) with different ballast compounds (red soil, bauxite, gravel, aluminium modified zeolite and lanthanum modified bentonite) to remove cyanobacterial biomass from water collected in Funil Reservoir (Brazil). We tested the effect of different cyanobacterial biomass concentrations on removal efficiency. We also examined if zeta potential was altered by treatments. Addition of low doses of PAC and chitosan (1–8 mg Al L-1) to the cyanobacterial suspensions caused flock formation, but did not settle the cyanobacteria. When those low dose coagulants were combined with ballast, effective settling in a dose-dependent way up to 99.7% removal of the flocks could be achieved without any effect on the zeta potential and thus without potential membrane damage. Removal efficacy was influenced by the cyanobacterial biomass and at higher biomass more ballast was needed to achieve good removal. The combined coagulant-ballast technique provides a promising alternative to algaecides in lakes, ponds and reservoirs.

KW - international

U2 - 10.1371/journal.pone.0178976

DO - 10.1371/journal.pone.0178976

M3 - Article

SN - 1932-6203

VL - 12

JO - PLoS One

JF - PLoS One

IS - 6

M1 - e0178976

ER -