|
|
Influence of organic matter on the character of aggregates formed during coagulation/flocculation process in dringing water treatment
Filipenská, Monika ; Pivokonská, Lenka ; Vašatová, Petra ; Pivokonský, Martin
Characteristics of aggregates (size, shape, density and porosity) affect separation efficiency. These characteristics come from properties of impurities (molecular weight and structure, charge density, affinity to water, etc.), coagulation parameters (pH, type and concentration of coagulants, etc.) and by physical conditions (shear rate and time of mixing). In this work, we describe relations between the size of aggregates and shear rate and moreover dependency on the characteristics of coagulated compounds. In order to understand dependency on compounds, flocs formed by kaolinite, Algal Organic Matter (AOM) and a mixture of the same were studied. There was found aggregates are bigger and more porous when AOM is present. The most striking result is that aggregates size changes in dependence on shear rate are not smooth in progress. A rapid change for the kaolinite-coagulant suspension and two rapid changes for the suspensions containing AOM were observed. These were attributed to various intermolecular interactions between floc components participating in coagulation at the different shear rate.
|
|
|
Are cyanobacteria capable of enhancing drinking water treatment? Sci-fi or reality?
Barešová, Magdalena ; Načeradská, Jana ; Novotná, Kateřina ; Pivokonská, Lenka ; Pivokonský, Martin
Drinking water treatment struggles with cyanobacteria and algae mainly on a seasonal basis especially when they decay and release amounts of cellular organic matter (COM). As COM is not only difficult to be removed but it also impacts the removability of other impurities, this paper aims to evaluate the effect of COM derived from two common cyanobacterial species– Microcystis aeruginosa and Merismopedia tenuissima on coagulation of other naturally occurring particles and molecules present in surface waters: kaolin suspension, humin substances and cells of M. tenuissima. Our findings show that higher COM concentrations do not have to disrupt coagulation. When COM interacts with other impurities, it can even lower coagulant doses and increase both turbidity and humic matter removal efficiencies.
|
|
|
The impact of algal organic matter on coagulation of other impurities present in surface waters
Barešová, Magdalena ; Pivokonský, Martin (advisor) ; Ambrožová, Jana (referee) ; Dolejš, Petr (referee)
Drinking water treatment is facing an adverse impact of algae especially when they extensively decay and release cellular organic matter (COM). As the character and consequently the removal efficacy of COM depends on the individual species, the thesis compares algal organic matter (AOM) derived from four common phytoplankton species: green alga Chlamydomonas geitleri, diatom Fragilaria crotonensis, and cyanobacteria Microcystis aeruginosa and Merismopedia tenuissima. To evaluate the differences between extracellular and cellular organic matter, we monitored the growth of those organisms and compared AOM obtained at different growth phases. As COM is not only difficult to coagulate, but also hinders the coagulation of other substances, the thesis investigates the effect of simultaneous coagulation of COM with other impurities present in surface waters: kaolin, humic substances (HS) or cyanobacterial cells of M. tenuissima. Coagulation behaviour was studied by the jar tests performed with single components and their mixtures with and without a coagulant (ferric or aluminium sulphate). Special emphasis was paid to proteinaceous COM of M. aeruginosa; to enhance the removability of proteinaceous matter we implemented pre-oxidation. Coagulation effectively removed turbidity (up to 99%) either of clay or...
|
|
|
Adsorption of organic compounds onto activated carbon in water treatment process
Kopecká, Ivana
The dissertation thesis focuses on the application of activated carbon for the removal of low molecular weight algal organic matter (AOM) produced by phytoplankton during drinking water treatment, as well as on the effect of AOM on adsorption of anthropogenic micropollutants contained in raw water. The results of this study have been published in international peer-reviewed journals in 4 papers and in 2 conference contributions. The efficiency of AOM removal was studied in laboratory equilibrium and kinetic experiments using different types of granular activated carbon and cellular peptides with molecular weight < 10 kDa produced by cyanobacterium Microcystis aeruginosa. It has been previously confirmed that these peptides are removed with difficulty during the conventional water treatment based on coagulation/flocculation processes and therefore, other methods need to be applied for their restriction. The effect of solution properties on peptide adsorption was assessed by the tests at different pH values and at variable ionic strengths. The negative impact of peptides on the adsorption of organic micropollutants present in raw water was simulated using competitive adsorption experiments with herbicides alachlor and...
|
|
|
Adsorption of organic compounds onto activated carbon in water treatment process
Kopecká, Ivana ; Pivokonský, Martin (advisor) ; Benešová, Libuše (referee) ; Janda, Václav (referee)
The dissertation thesis focuses on the application of activated carbon for the removal of low molecular weight algal organic matter (AOM) produced by phytoplankton during drinking water treatment, as well as on the effect of AOM on adsorption of anthropogenic micropollutants contained in raw water. The results of this study have been published in international peer-reviewed journals in 4 papers and in 2 conference contributions. The efficiency of AOM removal was studied in laboratory equilibrium and kinetic experiments using different types of granular activated carbon and cellular peptides with molecular weight < 10 kDa produced by cyanobacterium Microcystis aeruginosa. It has been previously confirmed that these peptides are removed with difficulty during the conventional water treatment based on coagulation/flocculation processes and therefore, other methods need to be applied for their restriction. The effect of solution properties on peptide adsorption was assessed by the tests at different pH values and at variable ionic strengths. The negative impact of peptides on the adsorption of organic micropollutants present in raw water was simulated using competitive adsorption experiments with herbicides alachlor and...
|
|
|
Coagulation of organic matter produced by phytoplankton
Načeradská, Jana ; Pivokonský, Martin (advisor) ; Benešová, Libuše (referee) ; Janda, Václav (referee)
This dissertation thesis focuses on the removability of algal organic matter (AOM) by coagulation during water treatment and also on the influence of AOM on the coagulation of other substances present in source water. Special emphasis is put on the description of coagulation mechanisms. The effectiveness of AOM removal by coagulation was investigated by coagulation tests performed with optimized doses of coagulants (aluminium or ferric sulphate) under different pH values. Peptides and proteins contained in cellular organic matter of cyanobacterium Microcystis aeruginosa were used in the experiments since they have been previously reported to disturb the coagulation process. Moreover, peptides and proteins underwent coagulation experiments together with kaolin particles, representing clay particles in turbid waters, in both the presence and absence of coagulants to investigate the effect of AOM on the coagulation of turbid waters. To enable the description of coagulation mechanisms, AOM were characterised in terms of charge, functional groups, molecular weight and ability to form dissolved complexes with coagulant metals. The experimental results demonstrated that the removability of peptides and proteins is greatly dependent on pH value and on the properties of the involved particles or molecules....
|
|
| |
guest ::
