Cyanobacterial blooms are global phenomena that can occur in calm and nutrient-rich （eutrophic） fresh and marine waters. Human exposure to cyanobacteria and their biologically active products is ...possible during water sports and various water activities, or by ingestion of contaminated water. Although the vast majority of harmful cyanobacterial products are confined to the interior of the cells, these are eventually released into the surrounding water following natural or artificially induced cell death. Electrochemical oxidation has been used here to damage cyanobacteria to halt their proliferation, and for microcystin degradation under in-vitro conditions. Partially spent Jaworski growth medium with no addition of supporting electrolytes was used. Electrochemical treatment resulted in the cyanobacterial loss of cell-buoyancy regulation, cell proliferation arrest, and eventual cell death. Microcystin degradation was studied separately in two basic modes of treatment： batch-wise flow, and constant flow, for electrolytic-cell exposure. Batch-wise exposure simulates treatment under environmental conditions, while constant flow is more appropriate for the study of boron-doped diamond electrode efficacy under laboratory conditions. The effectiveness of microcystin degradation was established using high-performance liquid chromatography-photodiode array detector analysis, while the biological activities of the products were estimated using a colorimetric protein phosphatase-1 inhibition assay. The results indicate potential for the application of electro-oxidation methods for the control of bloom events by taking advantage of specific intrinsic ecological characteristics of bloom-forming cyanobacteria. The applicability of the use of boron-doped diamond electrodes in remediation of water exposed to cyanobacteria bloom events is discussed.
Sensors based on in vivo measurements of photosynthetic pigments fluorescence enable real-time phytoplankton monitoring with high spatial and temporal resolution. A combination of chlorophyll a (CHL) ...and phycocyanin (PC) fluorescence sensors was used for phytoplankton quantification and differentiation in two small water bodies, Koseze Pond and pond in Hotinja vas. The high correlation of CHL and PC fluorescence signals with biovolume was confirmed during the two-year monitoring in anatural pond environment in spite of a seasonal succession of the phytoplankton. Additionally, disturbances of the sensors were investigated. Water bodies containing predominantly algae yielded false positive signals of the PC sensor, which reached up to 1% of the intensity of the CHL signal. Similarly, underestimated counts of cyanobacteria measured with CHL fluorescence sensor can be adjusted using PC fluorescence sensor.
Cyanobacterial blooms in fresh water bodies have a serious negative impact on human, animal and environmental health. The impact of electro-oxidation of water containing Planktothrix rubescens in ...electrolytic cell equipped with diamond electrodes has been tested. The treatment had an immediate effect on cyanobacterial phycocyanin and chlorophyll fluorescence response and total cell biovolume. Cyano-bacterial number reduced for 80 % 130 h after a single treatment of 500 mL of a water sample through electrolytic cell with a flow rate 1 L/min. Obtained results indicate a great potential of the method for in-lake cyanobacterial control.
The number of harmful cyanobacterial blooms has increased significantly at the global level in recent years. One of the characteristics of cyanobacteria that gives them advantage over other ...phytoplankton organisms are auxiliary photosyntheticpigments, such as phycocyanin. This fluorescent pigment emits light at a different wavelength as chlorophyll and can therefore be used for detection of cyanobacteria in situ. In this study we used submersible phycocyanin fluorescence sensors and compare their voltage output to concentration of extracted phycocyanin, cell counts and biovolume. The relation was linear in all three cases; however, the variability of regression line slopes between different cyanobacteria strains was high in the case of PC extract concentration and cell count. The highest uniformity in the linear fits was between fluorescence signal and biovolume therefore making it the best candidate for fluorescence sensor voltage output conversion. In the context of this work we also compared different methods for PC extraction. Modifying the equations by subtracting the absorption at 750 nm almost entirely reduces the false PC concentration estimation due to sample turbidity.
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•An analytical method for 8 pharmaceuticals and 2 pesticides was successfully validated.•Most of the selected compounds were detected in wastewater samples.•The advanced oxidation ...treatments of compounds were tested under laboratory conditions.•Boron-doped diamond and mixed metal oxide electrodes revealed high degradation efficiency.•The prototype cell could be a feasible option to upgrade wastewater treatment plants.
The presence of pharmaceuticals and pesticides in the environment has been frequently confirmed and has been recognized as a potential threat to the environment. This paper describes an advanced wastewater treatment process based on the electrochemical oxidation of pollutants, and the development of a sensitive analytical method to monitor the analytes in wastewater samples comprised of solid phase extraction followed by LC–MS/MS analysis. The analytical method was successfully validated and achieved low limits of quantification (2.5–12.5ng/L).
In our survey of some Slovenian wastewater samples, the occurrence of seven compounds from the list of ten monitored pollutants was confirmed and quantified. Bisoprolol, carbamazepine, ciprofloxacin, and metoprolol were determined in every assayed sample, while diclofenac reached the highest concentration (2μg/L). Therefore, under laboratory conditions the degradation efficiency of investigated compounds by various electrode materials, including boron-doped diamond (BDD), mixed metal oxide (MMO), platinum electrode, and high voltage sparks (HVS) were tested. The applicability of methodologies was evaluated on a synthetic mixture comprised of eight frequently prescribed pharmaceuticals (bisoprolol, carbamazepine, ciprofloxacin, clofibric acid, diclofenac, fluoxetine, imatinib and metoprolol) and two pesticides (atrazine, simazine). The BDD and MMO electrodes showed >85% degradation in 60min of treatment for the majority of the compounds, while the platinum electrode and HVS revealed low overall degradation efficiency. In addition, the BDD electrodes demonstrated an operational efficiency up to 70% also in a complex matrix of wastewater samples.
Based on our observations of the prototype electrolytic cell degradation efficiency of some pollutants commonly presents in wastewaters, one can assume that this new technology could be a viable and feasible option to upgrade existing wastewater treatment plants in order to achieve a significantly greater cleaning efficiency, and to lessen the ecological burden.
