Impacts of Potassium Permanganate and Powdered Activated Carbon on Cyanotoxin Release

Abstract

Bench-scale trials were performed to (1) expose Microcystis aeruginosa cells to potassium permanganate (KMnO 4 ) doses of 1, 3, and 5 mg/L at contact times (CTs) of 15, 30, and 90 min, pH levels of 7 and 9, and turbidities of 0.1, 5, and 20 ntu, respectively;(2) compare the impacts of oxidation alone and oxidation plus powdered activated carbon (PAC) for the final 60 min of CT; and (3) evaluate the impact of these treatment conditions on extracellular microcystins (MCs), extra-plus intracellular (combined) MCs, cell membrane integrity, and chlorophyll a concentrations. Toxin releases from the cells were observed at both pH levels. The greatest toxin releases were observed at the lowest KMnO 4 doses. The toxin releases were accompanied by relatively stable total cell counts, increases in membrane-compromised cells, and decreases in chlorophyll a. The application of 10 mg/L PAC resulted in extracellular toxin concentrations that were markedly lower than those observed in oxidant-only situations.

Advancing lake and reservoir water quality management with near-term, iterative ecological forecasting

“…If managers had access to iterative, near-term water quality forecasts, they could act today to prepare for or preempt future water quality impairment. For example, knowing in advance that a phytoplankton bloom would occur next week in a drinking water supply would allow managers to initiate interventions in the reservoir (e.g., add algaecides, activate a mixing system), optimize water treatment for toxin removal (e.g., alter levels of potassium permanganate and activated carbon; Dugan et al 2018), or change the depth at which drinking water is extracted for water treatment. Forecasts of other water quality variables that could be useful for water managers include water temperature to determine dam withdrawal schedules (Pike et al 2013, Weber et al 2017, organic matter concentrations to preempt potentially carcinogenic disinfection by-product (DBP) formation (Tomlinson et al 2016), hypolimnetic dissolved oxygen (DO) to prevent the release of metals and nutrients from sediments (Gerling et al 2016, Munger et al 2019, and the concentrations of metals and other contaminants to ensure drinking water safety.…”

Recent Advancements in the Removal of Cyanotoxins from Water Using Conventional and Modified Adsorbents—A Contemporary Review

“…We will compare the performance of coal-based adsorbents, coconut-based activated Various engineering controls have engendered a range of success in the removal of HAB toxins. Some commonly used engineering controls at drinking water treatment plants (DWTPs) are filtration, ozonation, coagulation, chlorination, reverse osmosis, photocatalysis, potassium permanganate, and powdered activated carbon [15,[29][30][31][32][33][34][35][36][37]. However, newer techniques are being explored, such as inactivation by ultrasound, biological approaches for neutralizing toxins, starch-based flocculation, silica-quaternary ammonium nanofilm-coated fiberglass mesh, and engineered polysaccharide lyases [33,[38][39][40][41].…”

Effects of harmful algal blooms on regulated disinfection byproducts: Findings from five utility case studies

“…Additionally, HABs can contribute to disinfection byproduct (DBP) formation in the treatment process (Li et al, 2012; Plummer & Edzwald, 2001; Tomlinson et al, 2016). DBP formation during a HAB event happens in two primary ways: AOM can serve as a DBP precursor (Chang et al, 2001; Pivokonsky et al, 2016; Yang et al, 2011; Zhao et al, 2018) and the treatment approaches employed to maximize cyanotoxin removal, such as increased disinfection dosing, can increase DBP formation (Dugan et al, 2018; Merel et al, 2010). The relationship between the occurrence of both toxin‐producing and non‐toxin‐producing cyanobacterial HABs in source water and the formation of DBPs has been well documented in laboratory studies (Chu et al, 2012; Fang et al, 2010a, 2010b; Goslan et al, 2017; Hua et al, 2017; Li et al, 2012; Plummer & Edzwald, 2001; Zhou et al, 2015).…”

“…Effective adsorption approaches for managing extracellular cyanotoxins include use of powdered activated carbon (PAC) and use of granular activated carbon (GAC) filters (USEPA, 2016a; Ho et al, 2011; Naceradska et al, 2017; Wang et al, 2007). Preoxidation (e.g., application of chlorine or permanganate prior to filtration) can be an effective treatment technology to control drinking water taste and odor issues commonly associated with HABs (Dugan et al, 2018). However, preoxidation by chlorine prior to organic removal during a HAB event may directly form DBPs and increase DBP precursor availability by inducing cell lysis and releasing intracellular material, such as cyanotoxins (Chu et al, 2017; USEPA, 2016a).…”