Jar Test Equipment Research Articles

The kinetics of nitrogen on surface water of a lotic environment (doi:10.4136/ambi-agua.159) (Portuguese)

The temporal transformation processes (ammonification and nitrification) of surface water nitrogen in the Meia Ponte River, Goias, Brazil, were quantified. Variability in the high- and low-flow periods, from June to November and from December to May, respectively, was measured. Kinetic assays and microbiological monitoring were carried out with water samples collected from the river in the urban part of the municipality of Goiânia, using modified jar test equipment. The concentrations of different forms of nitrogen, temperature, pH and nitrifying bacteria (NMP/100 mL) were monitored. Under these conditions, in the high-flow periods there were (1) an increase in nitritation; (2) a decrease in the concentration of total ammonia nitrogen, nitrite and Nitrosomonas (NMP/100 mL). In the low-flow periods there were (1) a decrease in nitritation; (2) an increase in the concentration of nitrite and Nitrosomonas (NMP/100 mL).

Determination of conventional velocity gradient (G) using CFD technique for a pilot-scale flocculation system

Research Article| December 01 2010 Determination of conventional velocity gradient (G) using CFD technique for a pilot-scale flocculation system Yamuna S. Vadasarukkai; Yamuna S. Vadasarukkai 1Department of Civil & Resource Engineering, Dalhousie University, Halifax NS B3J 1Z1, Canada Search for other works by this author on: This Site PubMed Google Scholar Graham A. Gagnon Graham A. Gagnon 1Department of Civil & Resource Engineering, Dalhousie University, Halifax NS B3J 1Z1, Canada Tel.: 902.494.3268 Fax: 902.494.3108; E-mail: graham.gagnon@dal.ca Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2010) 59 (8): 459–470. https://doi.org/10.2166/aqua.2010.081 Article history Received: August 26 2009 Accepted: March 22 2010 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Yamuna S. Vadasarukkai, Graham A. Gagnon; Determination of conventional velocity gradient (G) using CFD technique for a pilot-scale flocculation system. Journal of Water Supply: Research and Technology-Aqua 1 December 2010; 59 (8): 459–470. doi: https://doi.org/10.2166/aqua.2010.081 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Achieving uniform mixing conditions are essential for the flocculation process to optimize floc size and avoid floc-breakup. Limited literature is available on establishing consistent operational conditions and procedures for pilot-scale flocculation systems, which have tank sizes smaller than full-scale and larger than jar-test equipment. In this study, the influence of mixing speeds on the determination of the conventional design parameter, the average velocity gradient (G), was investigated for pilot-scale paddle flocculators. The pilot-scale plant for this paper was hosted at the J.D. Kline Water Supply Plant (JDKWSP) in Halifax, Canada. Computational fluid dynamics (CFD) was evaluated as an alternative design technique and compared against traditionally used empirical-based calculations. Comparison of both approaches showed that the G-values of empirical method were substantially higher than the predicted values for rotational speeds greater than 5 rpm. In contrast, CFD predictions found that G-values used for tapered paddle flocculation process (up to 60 s−1) could be achieved at lower rotational speed (around 15 rpm), which minimizes the power input required for mixing. The practical implications of operating at higher than required G-values relates to potential negative consequences such as floc break up, and the reliance of chemical additives to avoid floc break-up. These very practical outcomes could impact the interpretation of findings from pilot-scale treatment systems. average velocity gradient (G), computational fluid dynamics, flocculation, hydrodynamics, pilot-scale water treatment This content is only available as a PDF. © IWA Publishing 2010 You do not currently have access to this content.

Dissolved air flotation of surface water for spiral-wound module nanofiltration pre-treatment

Bench-scale dissolved air flotation (DAF) of Tagus River surface water (Valadas, Portugal) was investigated as pre-treatment for spiral-wound module nanofiltration (SWNF). Before the DAF, a coagulation/flocculation of the surface water was performed using aluminium sulphate, ferric chloride and chitosan coagulants and several commercial coagulant aids. The coagulation/flocculation experiments were carried with 2 L of surface water in a jar-test equipment at room temperature. The DAF performance to remove colloidal matter and suspended solids was evaluated through the measurement of the silt density index (SDI) and the modified fouling index (MFI) of the treated water. The air saturation pressure was varied between 300 and 600 kPa and the recycle ratio between 5 and 50%. The DAF without coagulation/flocculation was not effective in the reduction of both the SDI and MFI, even at a high DAF recycle ratio of 50%. The use of coagulants improved the DAF efficacy in reducing the fouling indexes and, for the optimal operating conditions, the MFI of the treated water was reduced by more than one order of magnitude. However, it was not possible to obtain treated water with SDI and MFI values below the recommended ones for SWNF. Further filtration of the DAF treated water with a 5 micron capsule filter was necessary to reduce the SDI below 5%/min and the MFI below 10 s/l 2. The integration of DAF with another process that removes the residual suspended solids and colloidal matter is, therefore, necessary to provide a good pretreatment for the SWNF of Tagus River surface water.

Volatilization Characteristics of Organic Compounds in the Coagulation Process

The emissions of two types of organic solutes during the coagulation process were simulated using Jar Test equipment and two additives, coagulant and polymer, to evaluate the volatilization characteristics under various operating conditions. The solute volatilization rates were found to be a function of the liquid mixing intensity, the chemical properties of the additives, and the properties of solutes, including molecular weight (M) , Henry’s law constant (H) , and water solubility (S) . The volatilization rates of the high H solutes increased sharply as the mixing intensity increased. Moreover, the volatilization rates of selected compounds were only slightly dependent on the coagulant concentrations due to the inorganic property of the coagulant. On the other hand, the effective volatilization reduction of the high H solutes in the existence of organic flocculant was a result of the enhancement of solutes solubility in water solutions. However, the above inhibition effects decreased significantly when ...

Coagulation of turbid waters using Moringa oleifera seeds from two distinct sources

Samples of turbid water prepared under laboratory controlled conditions were tested using natural coagulant-flocculant Moringa oleifera seeds from Burundi, Central Africa, and from Mahajanga, Madagascar. Coagulation-flocculation and sedimentation experiments were conducted using jar test equipment. For these tests, 5% Moringa oleifera solutions (w/w in water) were prepared using shelled and non-shelled seeds from the aforementioned countries. The results show that, in both cases, the shelled seeds provide much higher turbidity removal than the non-shelled ones. In addition, the volume of sludge produced was approximately 30% of that of conventional coagulants such as alum. Finally, it was concluded that seeds from Burundi were of superior quality than those of Madagascar. In fact, higher dosages of these seeds, of up to four times, were required in order to attain the same level of turbidity as the Burundi seeds.

Flocculation/Flotation/Ultrafiltration Integrated Process for the Treatment of Cork Processing Wastewaters

Membrane fouling is the major problem in the treatment by ultrafiltration (UF) of the cork processing wastewaters. This problem leads to drastic reduction on the permeate fluxes and has been associated with wastewaters phenolic/tannic colloidal matter. The present work proposes a flocculation/flotation/ultrafiltration integrated process for the treatment of these wastewaters. A flocculation study was carried out in jar-test equipment with chitosan. The zeta-potential and the particle size were monitored at different pH values and for different chitosan concentrations. The results showed an increase of the zeta-potential when chitosan is added and a significant increase of the effluent particle size with the decrease of the pH. A dissolved-air flotation study was performed with the flocculated wastewater. The parameters varied were the operating pressure and the recycle ratio. It was observed that for higher pressures and at a recycle ratio of 0.19 the polyphenols removal was higher. The UF experiments were carried out in flat-sheet cells of 13.2 cm2 of membrane surface area at transmembrane pressures of 1-3 bar. A commercial membrane (Ropur-TS60) and four cellulose acetate membranes with molecular weight cutoff (MWCO) ranging from 4.5 to 86 kDa were used. The flocculation/flotation pretreatment led to the enhancement of the UF permeate fluxes. For the membrane with higher MWCO, the permeate flux enhancement reached 130%.

Use of Moringa Oleifera Seeds as a Primary Coagulant in Wastewater Treatment

Samples of municipal and industrial wastewaters were treated by coagulation-flocculation and sedimentation, using a crude water extract of dry Moringa oleifera seeds as a primary coagulant. The quality of the treated wastewater was analyzed and compared to that of the wastewater treated with alum. Experiments were conducted at various dosages of the crude 5% (wt/v) water extract of dry shelled and non-shelled Moringa oleifera seeds, using jar-test equipment. Parameters of quality of the wastewaters were measured before and after the treatment to evaluate the removal efficiency on the major pollutants of concern in wastewater treatment, such as suspended solids, chemical oxygen demand (COD), nutrients (phosphorus and nitrogen), microorganisms and heavy metals. Results showed that Moringa oleifera seeds were efficient as a primary coagulant in wastewater treatment for removal of suspended solids and microorganisms, and also removal of some metals. Nutrients and COD were not successfully removed. COD and nutrients were somehow increased by coagulation using Moringa oleifera seeds. Compared to alum, Moringa oleifera seeds produced 4 to 6 times less sludge volume. Alum was found to be quite effective in phosphorus removal. The increase in COD and nutrients observed in the case of Moringa oleifera seeds might be avoided by using purified proteins instead of the crude water extract.

Influence of Operating Parameters on Turbidity Removal by Coagulation with Moringa Oleifera Seeds

A model turbid water was treated with Moringa oleifera seeds as a natural coagulant and various phenomena like coagulation - flocculation and sedimentation were observed in detail using jar-test equipment under laboratory conditions. Influence of pH, temperature, cation concentration and anion concentration of test water was studied. Also investigated was the effect of intensity and duration of rapid mixing as well as slow mixing on turbidity removal. Experiments were conducted at optimum dosage of a crude 5% (wt/v) water extract of dry non-shelled Moringa oleifera seeds. It was found that variation of pH, cation concentration, anion concentration, and rapid mixing did not significantly affect the coagulation activity of Moringa oleifera seeds, while temperature and slow mixing did. Lower temperatures increased the residual turbidity, and in case of slow mixing, an optimal intensity and duration of 40 RPM and 40 minutes respectively were found, which corresponds to a velocity gradient G equal to 25 sec−1 ...

Treatment of Effluents from Hemp-Based Pulp and Paper Industry I. Waste Characterization and Physico-Chemical Treatability

This study was conducted to determine the wastewater characteristics as well as the treatment alternatives for the Tafköprü Pulp and Paper Mill in Turkey. The physico-chemical treatability study was conducted by standard Jar-test equipment. The highest COD removal efficiency obtained was 96% for the paper machine, 50% for the alkali extraction and 20% for the bleaching effluents by using alum as coagulant. The colour removal efficiency was around 80% for the alkali extraction effluents.

Jar Tests Improve Water Quality

Jar test procedures, significance, and test equipment are discussed. The jar test determines the most effective chemical coagulant or combination of coagulants for treatment of water from a particular raw water source.