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Cyanobacteria: Eutrophic Freshwater Systems
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Water Resources and Hydrological Systems, 2020
Like any phytoplankton, bloom proliferation of blue-green algae reduces water quality in terms of human water use but also results in a reduction in diversity of the aquatic species assemblage at all trophic levels. The presence of “pea soup green” water, the accumulation of malodorous decaying algal cells, and the buildup of sediments rich in organic matter lead to user avoidance with the associated problems and implications for water quality management. The most obvious sign of an advanced blue-green algae bloom is the formation of green “scum,” which leads to deoxygenation of underlying waters, subsequent fish kills, foul odors, and lowered aesthetic values of affected waters.[6] In addition, certain genera and species produce taste and odor compounds, typically geosmin and 2-methyl iso-borneol, which cause non-hazardous but unpleasant problems for suppliers and users of potable water.[4]
Creating Microbial Quality in Drinking Water
Published in Edwin E. Geldreich, Microbial Quality of Water Supply in Distribution Systems, 2020
Massive blooms of algae (green and blue-green species, predominately) often occur in summer, being stimulated by high concentrations of inorganic N and P. Most algal blooms occur when N and P concentrations reach 0.8 and 0.4 mg/l, respectively. A bloom condition has been arbitrarily defined as an algal density of 500 cells or more per milliliter of raw source water.127 When this condition occurs, organisms clog treatment filters, algal cell clumps provide bacterial protection from disinfection exposure, and disinfectant demand increases. Some of the blue-green algae (Cyanobacteria) can produce toxins that, if ingested in sufficient concentration, may cause gastrointestinal upsets.120,128,129 Blue-green algal blooms also create a problem of taste and odor as a consequence of geosmin production in concentrations that exceed a threshold point.130 Geosmin is also produced by actinomycetes,131 particularly by members of the genus Streptomyces, growing in stagnated, warm, surface waters used in water supply treatment.
Organic Chemicals in Drinking Water
Published in Joseph Cotruvo, Drinking Water Quality and Contaminants Guidebook, 2019
Drinking water treatment plants drawing from source surface waters prone to summer algal blooms must contend with potential algal blooms and be prepared to respond rapidly. Observable source water conditions could include color, suspended cells and filaments, surface scum and huge masses of aggregated algae. Frequently production of potent taste and odor producing compounds such as geosmin and 2-methylisoborneol occur simultaneously, generating musty off tastes in the drinking water that some people can detect at less than 20 parts per trillion (ppt).
Removal of Taste and Odor Causing Compounds from Drinking Water Sources by Peroxone Process: Laboratory and Pilot Scale Studies
Published in Ozone: Science & Engineering, 2021
Malhun Fakioglu, Hazal Gulhan, Hale Ozgun, Mustafa Evren Ersahin, Izzet Ozturk
Cyanobacteria and some actinomycete species have generally been related to the taste and odor of water. Earthy and musty taste and odor of water generally resulted from geosmin and 2-methylisoborneol (MIB) compounds that are metabolites of those microorganisms (Chorus and Bartram 1999; Juttner and Watson 2007; Lee et al. 2017; Srinivasan and Sorial 2011; Suurnakki et al. 2015). MIB and geosmin are tertiary alcohols with similar structure and solubility, that can be detected by humans even at very low concentrations since their odor threshold value is approximately ~10 ng/L (Hobson et al. 2010; Newcombe et al. 2010). Cyanobacteria in water bodies produce MIB and geosmin as intracellular compounds, that are usually released into the water during the death and biodegradation of cyanobacteria (Hobson et al. 2010; Matsushita et al. 2008; Srinivasan and Sorial 2011; WHO [World Health Organization] 2015). Quality and environmental conditions of a water body such as high nitrogen and phosphorus content, high water temperature, long hydraulic retention time, and stable stratification increase the occurrence of cyanobacterial blooms in fresh water bodies, and lead to a considerable amount of MIB and geosmin production (Srinivasan and Sorial 2011; WHO [World Health Organization] 2015). On the other hand, MIB and geosmin-producing actinomycetes grow mostly on land, and reach water bodies via run-off (Hobson et al. 2010).
Use of hybrid microcapsules, chitosan-methyl esterified sericite-tannin, for the removal of harmful lake algae and nutrient
Published in Environmental Technology, 2020
Harmful algal bloom, which is represented by various complex factors, such as eutrophication of the lake and decrease of the flow rate, has become a global environmental problem [1]. The harmful algal bloom phenomenon is known to be very dangerous to humans, and is likely to cause direct damage. Drinking large quantities of cyanobacteria with toxins is able to cause vomiting and stomach cramps, and long-term use can lead to death [2]. In addition, when a harmful algal bloom grows, fish and aquatic creatures are killed, causing a toxic smell, and the aquatic ecosystem of the area is destroyed [3,4]. Microcystis and Anabaena are the representative harmful alga that causes summer algal blooms in Korea, and it is commonly found in fresh water, such as lakes or reservoirs. It causes microcystin and saxitoxin toxicity that destroy aquatic ecosystems [5]. Geosmin is harmless to the human body, but causes the water to develop a strong odour and can cause animal death [3]. The first animal death from algae occurred in Australia in 1878 due to toxins from microcystins produced by cyanobacteria [2,6]. Since then, damage to livestock and wildlife from geosmin and microcystin toxins has been reported worldwide [2]. Although reports have not yet been made in Korea, the possibility of damage cannot be excluded. In addition, when a harmful algal bloom grows, the cost of water treatment is high [1,4]. Therefore, in order to cope with the algal bloom phenomenon, the algae and the nutrients need to be simultaneously removed.