Effect of clariflocculator and pulsator based sedimentation technology and poly-aluminium chloride coagulant type on the efficiency of the water treatment plant

Abstract Polyaluminium chloride (PAC) with different basicity is used as a coagulant in most drinking water treatment plants (WTP). The aluminium concentration in PAC and its hydrolysis mechanism varied with the basicity of PAC. Incremental addition of PAC changes various Physico-chemical properties and turbidity removal mechanisms in water. Water treatment plants use the PAC concentration beyond its optimum dose without considering other aspects, including residual aluminium concentration. In the present work, the effect of high and medium basicity of PAC on different Physico-chemical properties like pH, zeta potential, and residual aluminium concentration of water was investigated. The pH of treated water decreases with the incremental addition of PAC, and an increase in zeta potential and residual aluminium concentration in treated water was evidenced. The change in pH after PAC addition is responsible for deciding the coagulation mechanism and efficiency of the coagulation process. pH reduction is comparatively more in high basicity PAC than medium basicity. PAC hydrolysis mechanism is controlled by the zeta potential of water and can be used as an alternative method to decide the optimum coagulant dose. The performance of clariflocculator and pulsator-based WTP was also evaluated for raw water from the same source. To reduce down the turbidity below the acceptable level, the coagulant requirement for clariflocculator based WTP is comparatively less than pulsator based WTP. The floc blanket in the pulsator gets disturbed with a slight change in the coagulant chemistry and quantity.

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Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination

Nanomaterials ◽

10.3390/nano11081883 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1883

Author(s):

Martin Pisárčik ◽

Miloš Lukáč ◽

Josef Jampílek ◽

František Bilka ◽

Andrea Bilková ◽

...

Keyword(s):

Silver Nanoparticles ◽

Biological Activity ◽

Zeta Potential ◽

Chain Length ◽

Alkyl Chain ◽

Chemical Properties ◽

Alkyl Chain Length ◽

Microbial Pathogens ◽

Physico Chemical ◽

Phosphorus Containing

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50–60 nm. A comparison with non-heterocyclic alkyltrimethylphosphonium surfactants of the same alkyl chain length showed better stability and more positive zeta potential values for silver nanodispersions stabilized with heterocyclic phospholium surfactants. Investigations of biological activity of phospholium-capped AgNPs are represented by the studies of antimicrobial activity and cytotoxicity. While cytotoxicity results revealed an increased level of HepG2 cell growth inhibition as compared with the cytotoxicity level of silver-free surfactant solutions, no enhanced antimicrobial action of phospholium-capped AgNPs against microbial pathogens was observed. The comparison of cytotoxicity of AgNPs stabilized with various non-heterocyclic ammonium and phosphonium surfactants shows that AgNPs capped with heterocyclic alkyldimethylphenylphospholium and non-heterocyclic triphenyl-substituted phosphonium surfactants have the highest cytotoxicity among silver nanodispersions stabilized by the series of ammonium and phosphonium surfactants.

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Characterization of NOM in a drinking water treatment process train with no disinfectant residual

Water Science & Technology Water Supply ◽

10.2166/ws.2009.569 ◽

2009 ◽

Vol 9 (4) ◽

pp. 379-386 ◽

Cited By ~ 12

Author(s):

S. A. Baghoth ◽

M. Dignum ◽

A. Grefte ◽

J. Kroesbergen ◽

G. L. Amy

Keyword(s):

Drinking Water ◽

Water Treatment ◽

Organic Carbon ◽

Distribution System ◽

Chemical Properties ◽

Drinking Water Treatment ◽

Building Blocks ◽

Fluorescence Excitation ◽

Water Treatment Process ◽

Water Treatment Plants

For drinking water treatment plants that do not use disinfectant residual in the distribution system, it is important to limit availability of easily biodegradable natural organic matter (NOM) fractions which could enhance bacterial regrowth in the distribution system. This can be achieved by optimising the removal of those fractions of interest during treatment; however, this requires a better understanding of the physical and chemical properties of these NOM components. Fluorescence excitation-emission matrix (EEM) and liquid chromatography with online organic carbon detection (LC-OCD) were used to characterize NOM in water samples from one of the two water treatment plants serving Amsterdam, The Netherlands. No disinfectant residual is applied in the distribution system. Fluorescence EEM and LC-OCD were used to track NOM fractions. Whereas fluorescence EEM shows the reduction of humic-like as well as protein-like fluorescence signatures, LC-OCD was able to quantify the changes in dissolved organic carbon (DOC) concentrations of five NOM fractions: humic substances, building blocks (hydrolysates of humics), biopolymers, low molecular weight acids and neutrals.

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A Study of the Physico - Chemical Characteristics of Raw , Filtered , and Treated Water at a Water Treatment Plant in Shebin El-Kom , Egypt

Egyptian Journal of Aquatic Biology and Fisheries ◽

10.12816/0011100 ◽

2014 ◽

Vol 18 (1) ◽

pp. 115-125 ◽

Cited By ~ 1

Author(s):

Elsayed A. Khallaf ◽

Mansour Galal ◽

S. El - Sbbagh ◽

Noura M. Nabet

Keyword(s):

Water Treatment ◽

Treatment Plant ◽

Water Treatment Plant ◽

Chemical Characteristics ◽

Treated Water ◽

Physico Chemical

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Cause of rapid monochloramine decay observed in treated water

Water Science & Technology Water Supply ◽

10.2166/ws.2016.173 ◽

2016 ◽

Vol 17 (3) ◽

pp. 752-758 ◽

Cited By ~ 1

Author(s):

Sam Hancock ◽

Martin Harris ◽

David Cook

Keyword(s):

Water Treatment ◽

Water Samples ◽

Pilot Scale ◽

The Other ◽

Biological Degradation ◽

Filter Media ◽

Rapid Decay ◽

Treated Water ◽

Water Treatment Plants ◽

The Impact

Rapid monochloramine decay has been observed in the product water of three River Murray water treatment plants (WTPs). Previous investigations identified that rapid monochloramine decay was microbiological in nature and observed in samples taken after media filtration but was absent in filtered water samples from a fourth WTP of similar design. The filters at the WTP not exhibiting rapid decay are backwashed with filtered non-disinfected water whereas the other WTPs backwash with treated chloraminated water. It was therefore hypothesised that backwashing filters with chloraminated water was the cause of the rapid monochloramine decay. A pilot-scale study was conducted to investigate the impact of backwashing with chloraminated water on the occurrence of microbiologically accelerated monochloramine decay. Additional samples were analysed to assess the impact of chloraminated backwash water on N-Nitrosodimethylamine (NDMA) formation and biological degradation of taste and odour compounds 2-methyl isoborneol (MIB) and geosmin in the filter media. Backwashing with chloraminated filtered water was concluded to be the cause of the observed rapid monochloramine decay, with rapid decay observed within 8 weeks for the filters backwashing with chloramines. Additionally, backwashing with chloraminated filtered water was observed to increase NDMA formation and impair the biological degradation performance of MIB and geosmin.

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Compost leachate treatment using polyaluminium chloride and nanofiltration

Open Chemistry ◽

10.1515/chem-2017-0015 ◽

2017 ◽

Vol 15 (1) ◽

pp. 123-128 ◽

Cited By ~ 2

Author(s):

Marjana Simonič

Keyword(s):

Zeta Potential ◽

Isoelectric Point ◽

Oxygen Demand ◽

Treatment Method ◽

Aluminium Chloride ◽

Leachate Treatment ◽

Physico Chemical ◽

Pre Treatment ◽

Ph Range ◽

Compost Leachate

AbstractLaboratory scale filtration tests utilizing leachate were conducted to investigate fouling and filtration performance of nanofiltration membranes. The work presented in this study is conducted on real samples rather than model water. Physico-chemical analyses showed that the leachate contained a lot of organic substances, exceeding 20000 mg/L O2 expressed as chemical oxygen demand. Proper pre-treatment method must be chosen in order to reduce fouling index. Coagulation pre-treatment using poly-aluminium chloride was chosen. Two thin film polysulfone membranes were used, purchased by Osmonic Desal. The focus of this research is to assess the influence of the particle size and zeta-potential of the colloidal fraction in leachate on nanofiltration performance. The isoelectric point of both membranes was 4.7 and 4.3, respectively. The fouled membranes were negatively charged over the pH range with isoelectric point shifting to the left (lower pH) indicating the foulant material mainly not charged. It was confirmed by its zeta-potential, measured at -2 mV.

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