A perspective of chemical treatment for cyanobacteria control toward sustainable freshwater development

Abstract

One of the most threatening consequences of eutrophic freshwater reservoirs is algal blooming which typically occur after the long a mega drought or/and irregular rainfall under influence of climate change. The long-term experiences of chemical treatment are known as a most practical effort to reduce health concerns from human exposure of harmful cyanobacteria as well as to preserve ultimate freshwater resources. Even though these conventional chemical treatment methods do not completely solve the algal residue problem in water treatment plant or directly in the water bodies, they still have big advantages as fast and efficient removal process of cyanobacteria due to cheaper, easier to manage. This review summarizes their chemical treatment scenarios of the representative coagulants, pre-oxidants and algaecides composed to chemical compounds which immediately may help to manage severe cyanobacteria blooms in the summer seasons.

Eutrophication: a threat to freshwater reservoirs and human health

“…Another option to combat the effects of eutrophication is to treat the water reservoir's great amount of algae. The conventional chemical treatments include peroxidation, algaecide application, biomanipulation or coagulation by inorganic compounds (Huh and Ahn 2017;Paerl 2018). Peroxidation by ozone, chlorine, chlorine dioxide, permanganate or ferrate is effective in promoting the coagulation of algal cells and is widely used in drinking water treatment, but they result in taste and odor occurrences due to higher oxidation strength.…”

“…Beyond that, chlorine and chlorine dioxide can produce undesirable DBP's, while ozone, chlorine or ferrate can induce release of cyanobacteria toxins. In general, ozone and permanganate are the most used techniques in this sort of water treatment (Huh and Ahn 2017).…”

“…They have largely focused on relatively small impoundments because the radius of effectiveness of their application can be quite limited, and they can be expensive to apply, deploy, and maintain. Copper-containing compounds can be effective algaecides, but they are toxic to various aquatic plants and animals, and the copper can precipitate out of the water column or sorb to suspended solids and accumulate in bottom sediments (Huh and Ahn 2017;Paerl 2018). Hydrogen peroxide (H2O2), on the other hand, is selective for cyanobacteria and has minimal adverse effects, but the H2O2 treatment must be repeated, especially if the potential bloom period is several months away, because its degradation to H2O is quick (Paerl 2018).…”

“…Their main disadvantage consists on their high price. These products present difficulties to be produced with high quality and purity (Huh and Ahn 2017).…”

Impact of copper sulfate application at an urban Brazilian reservoir: A geostatistical and ecotoxicological approach

“…Despite the ecotoxicological and human health implications of copper sulfate, it offers an easy and relatively inexpensive technique for water body management, producing a rapid environmental response (Padovesi-Fonseca and Philomeno, 2004;Kansole and Lin, 2017). Nevertheless, the use of copper sulfate is not the only option for water quality management (Beaulieu et al, 2005;Huh and Ahn, 2017). Other effective methods for the control of algae and cyanobacteria include the use of hydrogen peroxide, which is associated with fewer longterm ecotoxicological impacts (Matthijs et al, 2012;Bauzá et al, 2014;Lürling et al, 2014).…”