The impact of algal properties and pre-oxidation on solid–liquid separation of algae (original) (raw)
Related papers
Water Research, 2010
13 The aim of this study was to compare the coagulation and flotation of different algae 14 species with varying morphology and algogenic organic matter (AOM) composition 15 in order to link physical and chemical algae characteristics to treatment. Microcystis 16 aeruginosa (cyanobacteria), Chlorella vulgaris (green algae), Asterionella formosa 17 and Melosira sp. (diatoms) were treated by coagulation with aluminium sulphate and 18 flotation. The AOM was extracted and treated separately. Analyses included cell 19 counts, dissolved organic carbon, aluminium residual and zeta potential. Removal 20 efficiencies in the range 94-99 % were obtained for each species. Cells, AOM and 21
Coagulation Process for Removing Algae and Algal Organic Matter-An Overview
Open Access Library Journal, 2020
In drinking water sources, seasonal algal blooms have augmented greatly during the last decades following the elevated temperature and nutrient loading in surface water because of agricultural and surface runoff. More than 95% of algal cells may be retained via coagulation/flocculation techniques. Nevertheless, algal organic matter (AOM) stays not eliminated well throughout coagulation, therefore it provokes many working dares in potable water treatment. This work aims to discuss the performance of coagulation on AOM reduction. The main pathway of algae and AOM reduction stays charge neutralization (CN) at an optimum pH of about 6.0. More research has to follow the reduction of low-molecular weight AOM, reluctant to coagulate, with additional treatment methods to diminish its negative influence on water safety. As dissolved microcystins (MCs) are efficaciously eliminated via CN, enhanced coagulation (EC) would be more suitable for their elimination. On the other hand, some precautions must be followed to guarantee that the acid injection has not a secondary impact in the form of algaecide treatment to avert the dissolved MCs concentration augmentation. Consequently, both algae and dissolved MCs may be efficiently removed by EC when appropriate rapid mixing and acid/coagulant dosage are guaranteed.
Water research, 2018
Algae and cyanobacteria frequently require separation from liquid media in both water treatment and algae culturing for biotechnology applications. The effectiveness of cell separation using a novel dissolved air flotation process that incorporates positively charged bubbles (PosiDAF) has recently been of interest but has been shown to be dependent on the algae or cyanobacteria species tested. Previously, it was hypothesised that algal organic matter (AOM) could be impacting the separation efficiency. Hence, this study investigates the influence of AOM on cell separation using PosiDAF, in which bubbles are modified using a commercially available cationic polyelectrolyte poly(N, N-diallyl-N,N-dimethylammonium chloride) (PDADMAC). The separation of Chlorella vulgaris CS-42/7, Mychonastes homosphaera CS-556/01 and two strains of Microcystis aeruginosa (CS-564/01 and CS-555/1), all of which have similar cell morphology but different AOM character, was investigated. By testing the cell s...
Eliminating Cyanobacteria and Controlling Algal Organic Matter-Short Notes
Open Access Library Journal, 2020
Coagulation and flocculation processes could reduce particulate algal cells efficiently , but they are not so performant in dealing with solubilized algal organic matter in potable water factories. This work reviews the main findings found in recent publications. Many techniques used in the water treatment industry encounter the problem of microalgae lysis, toxin release, and degradation. Indeed, chemical coagulants such as alum and pre-oxidation injecting chlorine can trigger demolition to algal cell integrity leading to the release of intracellular organic matter. As suggestion, chlorination could be decreased to the disinfection (i.e., before sand filtration) averting pre-disinfection and keeping the post-disinfection. Moreover, algae recuperation instead of its removal in drinking water treatment plants remains an encouraging outlook especially if the surface water arrives from dams where algae blooms happen usually. Algae remain a sustainable energy resource with a huge capacity for CO 2 fixation. The micro-algae could be developed in photo-bioreactors or in open ponds. A fresh attracting domain of investigation would be fast and simultaneous algal biodiesel production with drinking water treatment in the biodiesel production/water treatment plant without chemicals use.
Influences of Various Aluminum Coagulants on Algae Floc Structure, Strength and Flotation Effect
Procedia Environmental Sciences, 2011
Floc structure and strength play important roles in particles separation in water treatment. In a jar test of coagulation/flocculation/dissolved air flotation (C/F/DAF) process, aluminium sulphate (AS) and polyaluminium chloride (PAC) were used as coagulants to treat the algal-rich water which had a high concentration of Microcysits aeruginosa (MA) cells. Two-dimension fractal dimension (D 2) and strength factor (SF) were used to represent the floc structure and strength respectively. The experimental results showed: meeting the appropriate dose range (measured in Al 3+) simultaneously, dose of PAC was less than AS; and treatment effect obtained by PAC was better than AS. Adding the moderate PAC, the algae flocs with highly branched structure and higher strength formed by bridging flocculation; this kind of algae flocs could firmly adhere to more tiny bubbles and be significantly more resistant to the hydraulic shear, so the performance of flotation separation using PAC could be improved compared with adding AS.
Saudi Journal of Biological Sciences, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Water, Air, & Soil Pollution, 2019
The process of growth of algae can be described using the images from microscopic analysis. The new approach to assessment of the growth dynamics of algae used the data of granulometric composition of liquid medium and the modified Avrami equation relating to the crystallisation process. This paper presents a comparison of both methods (granulometric and microscopic) for the analysis of the dynamics of changes in the growth of algae in wastewater. The experimental setup consisted of four glass tanks filled with biologically treated sewage, in which algae grew. The cultivation of algae was carried out for 8 weeks. During this period, the granulometric analysis and microscopic observations of sewage were conducted. The study demonstrated that with increase in the size of flocs in treated sewage, biomass of algae was also increased. Therefore, the results obtained with the method of laser diffraction are in agreement with microscopic observation of flocs. Granulometric analysis could be, next to microscopic analysis, a method for the estimation of the dynamics of changes in the growth of algae in sewage. This knowledge will allow to selection of a suitable method of wastewater treatment and algal separation.
Enhanced Coagulation for Algae Removal in a Typical Algeria Water Treatment Plant
Environmental Engineering and Management Journal, 2017
This work aims to study the physicochemical and biological parameters of Boukerdene Dam's water and treated water at different steps of the treatment processes in Sidi-Amar's Station (Tipaza, Algeria) with a particular interest to the phytoplankton. This work is also related to the demonstration of the enhanced coagulation (EC) process as an efficient method in algae and organic matter (OM) removal from surface water by its application in jar tests. The diversity of the phytoplankton shows the presence of 21 genera comprising 30 algae species out of 8 samples taken from the Boukerdene Dam. Among the identified genera, seven of them are responsible for the unpleasant tastes and odours of water; six others are responsible for filter fouling. Generally, the conventional drinking water treatment processes employed at this water treatment plant shows a limited efficiency of OM and algae removal. The novelty of this work is that the jar tests of EC (pH 6 and alum dose 15 mg L-1) as only one stage of water treatment, without chlorination and filtration, improve the removal of OM and algae at 97 to 99%, respectively.